Types of Autoimmune Conditions

Type 1 diabetes occurs when the immune system's T cells destroy the insulin-producing beta cells in the pancreas, eventually leaving the body unable to produce enough insulin on its own. The process is often marked by specific autoantibodies, including anti-GAD65, anti-insulin, and anti-islet cell antibodies, that can appear years before symptoms do. People with type 1 diabetes carry a meaningfully higher risk of developing other autoimmune conditions, most often autoimmune thyroiditis and celiac disease, which is part of why clinicians often screen for both.

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Hashimoto's affects the thyroid, a small gland in the neck. The immune system is thought to gradually inflame and damage thyroid tissue, mediated by antibodies against thyroid peroxidase and thyroglobulin along with T-cell activity that drives progressive fibrosis of the gland. Over time this can lower thyroid hormone output and lead to an underactive thyroid (hypothyroidism). It often involves a goiter, an enlarged thyroid. Hashimoto's is the most common autoimmune thyroid condition and the most common cause of hypothyroidism in regions where iodine intake is adequate. A 2022 meta-analysis estimated the condition affects roughly 7.5 percent of adults worldwide, though reported rates vary widely by region and screening method. It is markedly more common in women, with a female-to-male ratio estimated between 7:1 and 10:1, and most often diagnosed between ages 45 and 55.

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Ord's thyroiditis affects the thyroid, the small gland in the neck, and is considered a close cousin of Hashimoto's within the spectrum of autoimmune thyroid disease. The immune system is thought to drive lymphocytic infiltration of the thyroid, mediated by T cells and thyroid autoantibodies, that leads to gradual destruction and fibrosis of thyroid tissue. Where Hashimoto's usually enlarges the thyroid into a goiter, Ord's tends toward atrophy, so the gland shrinks rather than swells, and research describes the two as sitting on a shared disease spectrum rather than as fully separate conditions. Both patterns move toward reduced thyroid hormone output and hypothyroidism. Autoimmune thyroid disease as a whole is common, with research estimating it affects up to about 5 percent of the general population in areas with adequate iodine intake, and it is markedly more common in women. Solid figures for the atrophic form specifically are harder to pin down, since many studies group it together with Hashimoto's rather than tracking it separately.

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Graves' disease is an autoimmune thyroid condition in which the immune system produces antibodies that bind to and stimulate the thyroid-stimulating hormone receptor, driving the thyroid to enlarge and overproduce thyroid hormone. The result is hyperthyroidism, which can bring on a racing heart, weight loss, heat intolerance, and anxiety, and a meaningful share of people with Graves' also develop eye involvement, known as Graves' ophthalmopathy. It affects an estimated 1 to 2 percent of the population and is about 5 times more common in women, most often appearing between ages 30 and 60.

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Addison's disease affects the adrenal glands, which sit atop the kidneys. The immune system is thought to gradually destroy the outer layer of the adrenal gland, the adrenal cortex, mediated in large part by antibodies against the enzyme 21-hydroxylase. This progressively reduces the gland's ability to produce cortisol and often aldosterone, the hormones that help regulate energy, blood pressure, and the body's stress response. Autoimmunity is understood to be the leading cause of Addison's disease in industrialized countries, and research describes a preclinical phase, sometimes lasting years, in which autoantibodies and mild hormone shifts are present before symptoms appear. Addison's disease is considered rare. One commonly cited estimate for the United States and Western Europe puts prevalence at roughly 1 in 20,000 people, and separate Norwegian registry data has reported a higher regional figure of around 144 per million, and it is generally described as more common in women.

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Autoimmune pancreatitis, type 1, affects the pancreas and is understood as the pancreatic expression of a broader condition called IgG4-related disease, which can also involve the bile ducts, salivary glands, kidneys, and lymph nodes. The immune system is thought to drive chronic inflammation of the pancreas, marked by elevated IgG4 antibody levels, dense lymphoplasmacytic infiltration, and a distinctive pattern of scarring called storiform fibrosis, and this swelling can be mistaken for a pancreatic tumor on imaging. Type 1 disease most often appears in the seventh decade of life and shows a strong male predominance. It is considered rare, and most of the available epidemiological data comes from Japan, where a nationwide survey identified thousands of affected patients, while research from Europe and other regions remains more limited, so a precise global prevalence figure is not well established.

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APS-1 is a rare inherited condition, caused by mutations in the AIRE gene, which normally helps the immune system learn to tolerate the body's own tissues. When AIRE is defective, the immune system is thought to lose tolerance toward several hormone glands and other tissues at once, most classically the parathyroid glands, the adrenal cortex, and the skin and mucous membranes that resist candida. Researchers describe this as an autosomal recessive disorder, meaning a person needs two altered copies of the gene, one from each parent, to develop it. APS-1 is genuinely rare in most populations and research describes it as having limited epidemiological data overall, though certain founder populations carry a much higher burden: reported prevalence reaches roughly 1 in 14,000 in Sardinia and 1 in 9,000 among Iranian Jews, with Finland and other Scandinavian countries also reporting elevated rates.

Read more about Autoimmune polyendocrine syndrome type 1 (APS-1, APECED)

APS-2 is a cluster in which the immune system is thought to target more than one hormone gland over time, most often combining Addison's disease with autoimmune thyroid disease and, in some people, type 1 diabetes. Unlike APS-1, it is not tied to a single known gene and instead is understood as a polygenic condition with incomplete penetrance, meaning genetic risk factors raise susceptibility without guaranteeing the condition will develop. It typically emerges in early adulthood, with peak onset in the third or fourth decade, and research describes it as roughly three times more common in women than in men. APS-2 is considered rare. Estimates vary across studies, with some research citing a prevalence near 1 in 20,000 and others reporting a lower range of about 1.4 to 4.5 cases per 100,000 people, reflecting how inconsistently the condition has been tracked across populations.

Read more about Autoimmune polyendocrine syndrome type 2 (Schmidt syndrome)

Autoimmune hypophysitis affects the pituitary gland, the small hormone-control center at the base of the brain. The immune system is thought to drive inflammation of the gland, seen as dense lymphocytic infiltration on biopsy, which can cause the pituitary to swell and then produce too little of one or more of its hormones, a pattern called hypopituitarism. Because the pituitary directs the thyroid, adrenal, and reproductive hormone systems, its effects can ripple outward into several other glands at once. It is particularly associated with pregnancy and the postpartum period, and research notes that other autoimmune conditions coexist in roughly a quarter to half of cases. Autoimmune hypophysitis is considered a rare disease, with some estimates placing incidence around 1 case per 9 million people per year, and a review of published cases through 2004 identified only a few hundred documented patients worldwide.

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Autoimmune oophoritis affects the ovaries, where the immune system is thought to selectively target the theca cells surrounding developing follicles, while leaving other ovarian cells more intact. This pattern of injury is one recognized driver of primary ovarian insufficiency, in which the ovaries lose normal function earlier than expected. Diagnosis is difficult because the accepted gold standard is ovarian biopsy, an invasive step rarely performed in practice, so most cases are inferred rather than confirmed. This condition often appears alongside other autoimmune endocrine conditions, especially Addison's disease. Because of these diagnostic limits, prevalence is hard to state precisely. Research estimates that autoimmune mechanisms may underlie roughly 4 to 30 percent of premature ovarian failure cases, a wide range that reflects how much uncertainty remains in identifying the autoimmune subtype specifically.

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Primary ovarian insufficiency means the ovaries slow down or stop their normal function before age 40, producing less estrogen and releasing eggs irregularly or not at all. It has several possible causes, including genetic factors, medical treatments such as chemotherapy, and, in a portion of cases, an autoimmune process such as autoimmune oophoritis. The older term 'premature ovarian failure' is being retired in favor of 'insufficiency' because research shows ovarian function can fluctuate and intermittently return rather than stopping permanently. A large meta-analysis estimated the global prevalence of primary ovarian insufficiency at roughly 3.5 to 3.7 percent of women, with rates varying by region, and among women with an identified cause, autoimmunity was estimated to account for around 10 percent of cases, a similar share to iatrogenic causes such as surgery or cancer treatment.

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Autoimmune orchitis affects the testicles, where the immune system is thought to target sperm-producing tissue or sperm themselves, largely through anti-sperm antibodies. The testicle is normally an immune-privileged site, meaning it is partly shielded from immune surveillance, and researchers believe infection, inflammation, injury, or surgery such as vasectomy can disrupt that barrier and trigger an immune response against sperm antigens. This is considered one contributor to male infertility, alongside other causes like varicocele and prior epididymo-orchitis. Research describes anti-sperm antibodies as present in roughly 5 to 12 percent of infertile male partners, though this reflects antibody presence broadly rather than a confirmed diagnosis of autoimmune orchitis itself, and reliable prevalence figures for the condition as a distinct diagnosis remain limited.

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Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside it, most often on the ovaries and pelvic structures, driving chronic inflammation, pain, and sometimes infertility. It is not classified as a confirmed autoimmune disease, and research describes it instead as an immune-mediated condition: studies show reduced natural killer cell activity, altered complement system proteins, and broader disruption of both innate and adaptive immunity in the pelvic environment, alongside a hormonal environment marked by excess estrogen signaling and progesterone resistance. These immune changes appear to help displaced tissue survive and grow outside the uterus rather than being cleared normally. Endometriosis is common, with research estimating it affects around 10 percent of women of reproductive age worldwide, and presentation ranges from severe pelvic pain to cases with few noticeable symptoms.

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Celiac disease is an immune-mediated reaction to gluten, a protein found in wheat, barley, and rye, that occurs in people with a genetic susceptibility carried by the HLA-DQ2 or HLA-DQ8 genes. Eating gluten triggers an immune response in the small intestine that produces characteristic autoantibodies against tissue transglutaminase and endomysium, and damages the intestinal lining by flattening the villi that normally absorb nutrients. Celiac disease affects an estimated 1 percent of people worldwide, though a large share of cases are believed to go undiagnosed, and presentation ranges from severe malabsorption to few or no digestive symptoms at all.

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Crohn's disease is a form of inflammatory bowel disease in which the immune system mounts an inappropriate response to intestinal bacteria in people who are genetically predisposed, producing patchy, full-thickness inflammation anywhere along the digestive tract, though it most often involves the end of the small intestine and the beginning of the large intestine. Over time this inflammation can lead to strictures (narrowing) or fistulas (abnormal connections between tissues) in as many as half of those affected. Crohn's disease has been rising in prevalence across the United States and Europe in recent decades, and researchers have also documented rising rates in newly industrialized regions as diets and environments shift.

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Ulcerative colitis is a form of inflammatory bowel disease affecting the colon and rectum. It is understood to arise from an interaction between genetics, environmental factors, gut microbiota, and an immune system that mounts a sustained inflammatory response against the colon's lining, producing continuous inflammation that begins at the rectum and extends upward in an unbroken stretch. Unlike Crohn's disease, it usually stays confined to the colon and affects the surface lining rather than the full thickness of the bowel wall. Research describes global incidence estimated at roughly 1 to 20 cases per 100,000 people yearly, with rates rising in newly industrialized regions. Ulcerative colitis tends to follow a bimodal age pattern, with one diagnosis peak in the second and third decades of life and a second later between ages 50 and 80.

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Autoimmune hepatitis affects the liver, where the immune system is understood to target liver cells, producing ongoing inflammation that can scar the liver over time if it stays active. The disease is thought to develop through a combination of genetic susceptibility, including certain HLA gene variants, and immune-regulation problems that allow the body to lose tolerance for its own liver tissue. It can come on suddenly, including as acute liver failure, or build quietly over years toward advanced fibrosis. Autoimmune hepatitis occurs worldwide, and research describes it as having a low, and likely underestimated, prevalence, since many cases are mild or go undetected until liver blood tests are checked for another reason. It shows a clear female predominance and can appear at any age.

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Primary biliary cholangitis affects the liver, specifically the small and medium bile ducts inside it. The condition is understood to involve a loss of immune tolerance toward mitochondrial proteins in the cells lining these ducts, triggering antibody and T-cell driven damage that slowly destroys the ducts, so bile backs up and, over a long time, can scar the liver. Genetics and environmental exposures are also thought to play contributing roles. It was formerly called primary biliary cirrhosis. A large 2025 systematic review and meta-analysis, drawing on 59 studies across 25 countries, found that prevalence and incidence vary significantly by region and have been rising over recent decades, likely reflecting both a true increase and greater detection. Primary biliary cholangitis shows a strong female predominance, with a female-to-male ratio estimated around 10 to 1.

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Primary sclerosing cholangitis affects the bile ducts inside and outside the liver. Its underlying cause is not fully understood, and researchers regard it as an immune-mediated disease based on a strong immunogenetic background. Chronic inflammation of the bile duct lining is thought to lead to fibrosis and progressive narrowing of the ducts, which can slow the flow of bile and, over years, contribute to cirrhosis. It is closely linked with inflammatory bowel disease, most often ulcerative colitis, with an association reported in up to 88 percent of people who have PSC in some study populations. A systematic review of population-based studies found incidence and prevalence rates that vary considerably by geographic region, and more recent data suggest diagnosed incidence has risen over recent decades. Unlike many autoimmune liver conditions, PSC most often affects middle-aged men.

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Autoimmune gastritis affects the stomach, specifically the acid-producing parietal cells in the upper stomach lining. It is understood to result from a T-cell mediated immune response directed against the parietal cell proton pump, working alongside autoantibodies against parietal cells and intrinsic factor, a protein needed to absorb vitamin B12. Over time this immune activity destroys parietal cells, so the stomach lining thins, acid production drops, and B12 absorption falls, a process closely tied to pernicious anemia, which can develop later. A 2024 clinical review estimated the prevalence of autoimmune atrophic gastritis at somewhere between 0.3 and 2.7 percent of the general population. It was once thought to mainly affect older women of Northern European descent and is now recognized across many populations and ethnic groups.

Read more about Autoimmune gastritis (AIG, autoimmune metaplastic atrophic gastritis)

Pernicious anemia develops as a downstream effect of autoimmune gastritis, centered on the stomach and the body's ability to absorb vitamin B12. Research describes it as a multifactorial autoimmune condition in which autoantibodies against parietal cells and intrinsic factor impair the stomach's ability to produce intrinsic factor and can also block it directly, so dietary B12 cannot be absorbed in the small intestine. Without enough B12, the body cannot make healthy red blood cells, and nerve tissue can also be affected over time. It is considered the most common cause of vitamin B12 deficiency anemia worldwide, and research notes that diagnosis remains challenging because of its varied presentations. Pernicious anemia is understood mainly as a disease of older adults, and it frequently occurs alongside other autoimmune conditions such as autoimmune thyroid disease and type 1 diabetes.

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Autoimmune enteropathy is a rare condition affecting the small intestine, in which immune dysregulation is understood to drive an attack on the cells lining the gut, flattening the villi so the bowel cannot absorb nutrients normally. It is seen most often in infants, where it typically appears within the first six months of life as severe, treatment-resistant diarrhea, and it has also been documented in adults, where it can be harder to recognize because it overlaps with other digestive disorders such as celiac disease. In some children, the condition traces to a specific gene mutation that disrupts a regulatory immune cell responsible for keeping the immune system in check. Because it is rare, research describes reliable prevalence figures as limited, and diagnosis relies on clinical evaluation, blood antibody testing, and biopsy findings.

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Eosinophilic esophagitis is an immune-driven condition of the esophagus, the tube connecting the throat to the stomach, and it is generally considered allergic and immune-mediated rather than classically autoimmune. Research describes the process as beginning when exposure to food or environmental allergens causes the esophagus lining to release signaling proteins that draw eosinophils, a kind of white blood cell, into the esophageal tissue. Over time this drives inflammation and narrowing of the esophagus, which can cause swallowing difficulty and, less often, food becoming stuck. A 2021 review published in JAMA estimated that EoE affects roughly 34 people per 100,000 in Europe and North America, and its recognized prevalence has risen over recent decades. It occurs in children and adults and is associated with other allergic conditions such as asthma and eczema.

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Eosinophilic gastroenteritis is an immune-driven condition in which eosinophils build up in the stomach, small intestine, or both, causing inflammation. Like eosinophilic esophagitis, it is understood as an allergic-type immune response, often connected to food sensitivities, and is considered immune-mediated rather than classically autoimmune. A 2015 analysis of a large United States insurance claims database estimated the standardized prevalence of eosinophilic gastroenteritis at roughly 8 per 100,000 people, making it genuinely rare. The same research found it was more common in young children than adults and identified a high rate of coexisting allergic conditions, close to half of those affected. Symptoms and severity depend on which layer and region of the digestive tract is involved.

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IgG4-related disease is an immune-driven, fibroinflammatory condition that can affect many organs, and in the digestive system it commonly involves the pancreas, where it is known as autoimmune pancreatitis, and the bile ducts, where it can closely resemble other liver and pancreas diseases. Research describes the process as involving a skewed immune response that drives infiltration of affected tissue by IgG4-producing plasma cells, leading to swelling and fibrosis in the organs involved. Because it was only recognized as a distinct entity in the past two decades, researchers describe its prevalence as still quite limited, though reviews note it appears more often in men in mid-to-later adulthood. In the digestive system, symptoms can include yellowing of the skin or eyes from blocked bile flow and an enlarged organ that can be mistaken for cancer on imaging.

Read more about IgG4-related sclerosing disease (IgG4-related disease, IgG4-RD)

Cronkhite-Canada syndrome is a very rare condition in which polyps grow throughout the digestive tract, most often the stomach, small intestine, and colon, along with distinctive changes to the skin, hair, and nails. Its underlying cause remains unknown, and research describes it as probably autoimmune, with inflammatory processes suspected to play a central role, though it is not a well-established autoimmune disease in the way conditions with confirmed autoantibodies are. It is genuinely rare. Research places the number of documented cases worldwide at several hundred since it was first described in 1955, with some estimates placing incidence around 1 per million people, meaning solid prevalence data are simply not available. Because CCS carries a meaningful risk of gastrointestinal cancer in some case series, ongoing monitoring and specialist care are an important part of managing it.

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Multiple sclerosis is a condition in which the immune system attacks myelin, the protective sheath around nerve fibers in the brain and spinal cord, along with the nerve fibers themselves. Autoreactive T cells and B cells cross an impaired blood-brain barrier and drive inflammation and progressive nerve damage, which is part of why MS symptoms and their severity vary so widely from person to person depending on which part of the central nervous system is affected. MS affects an estimated 2.3 million people worldwide and is typically diagnosed between ages 20 and 50, occurring roughly 2 to 3 times more often in women than men.

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Myasthenia gravis affects the neuromuscular junction, the point where a nerve signals a muscle to contract. Autoantibodies target key molecules at this junction, most often the acetylcholine receptor and, in a smaller group of people, muscle-specific kinase (MuSK) or a related protein called Lrp4, and this reduces the density and function of the receptors that let the signal through. The result is fatigable weakness, muscle strength that drops with repeated use and recovers with rest. Myasthenia gravis is considered a rare disease and the most common disorder of the neuromuscular junction, with an estimated 60,000 people affected in the United States. Onset age varies widely, with the disease tending to peak in younger women and older men, and researchers expect the number of people living with it to grow as the population ages.

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Lambert-Eaton myasthenic syndrome also affects the neuromuscular junction, and the trouble sits on the nerve side of that connection. In most people, antibodies target voltage-gated calcium channels on the presynaptic nerve terminal, which reduces the release of acetylcholine, the chemical messenger that triggers muscle contraction. A large share of cases occur as a paraneoplastic syndrome linked to an underlying cancer, most often small-cell lung cancer, so a new diagnosis usually prompts cancer screening, and other cases arise as a primary autoimmune condition without a tumor. LEMS is considered a rare condition. Research describes an annual incidence estimated between roughly 0.09 and 0.3 per million people and an overall prevalence around 1 per million, with a median age at diagnosis near 60 and a slight female predominance.

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Guillain-Barre syndrome is an acute condition in which the immune system attacks the peripheral nerves, the nerves outside the brain and spinal cord. It's usually preceded by an infection, often by one to two weeks, and current understanding is that antibodies produced against the infectious trigger cross-react with components of the nerve, damaging the myelin coating or the nerve fibers themselves. The classic demyelinating form accounts for the large majority of cases in Western countries, while axonal forms are more common in parts of Asia and Central and South America. GBS is described as a rare condition and the leading cause of acute paralytic neuropathy worldwide, with incidence varying by region and the infections circulating locally. Unlike most conditions here, it's usually a single, self-limited illness rather than a lifelong one.

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Chronic inflammatory demyelinating polyneuropathy is often described as the chronic relative of Guillain-Barre syndrome. The immune system is understood to attack the myelin of the peripheral nerves, and in some people the underlying nerve fibers as well, and the course builds and continues over eight weeks or longer rather than peaking quickly, and it can be steadily progressive or come in relapses. CIDP is considered a rare condition, and estimates of how common it is vary a good deal depending on the diagnostic criteria and population studied. Older systematic reviews describe an incidence of roughly 0.2 to 1.6 and a prevalence of roughly 0.8 to 8.9 per 100,000 people, while a more recent U.S. claims-based analysis found a higher adjusted prevalence, around 23 per 100,000, suggesting the condition may be more common, or more frequently recognized, than earlier figures suggested.

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Acute disseminated encephalomyelitis is a sudden, usually one-time burst of inflammation and demyelination across the brain and spinal cord. It's understood as an immune reaction, often triggered after a viral infection or, rarely, a vaccination, in which the immune system attacks myelin, the insulating coating around nerve fibers, in the central nervous system. It is more common in children and is most often monophasic, a single event rather than a recurring illness, though relapsing forms have been reported and can be hard to distinguish from multiple sclerosis. Research describes ADEM as a rare condition, with one widely cited estimate placing overall incidence around 0.4 per 100,000 people per year and no particular gender, age group, or region disproportionately affected. Outcomes in children are generally favorable, though cognitive effects can persist even when other symptoms resolve.

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Anti-NMDA receptor encephalitis is a form of brain inflammation in which the immune system makes antibodies against the NMDA receptor, a protein nerve cells use to communicate, predominantly targeting a piece of it called the GluN1 subunit. This is thought to impair glutamate signaling between neurons and produces a mix of psychiatric and neurological symptoms. It can appear on its own or alongside a tumor, most often an ovarian teratoma in women of childbearing age, though it also occurs in men and children without an identifiable tumor. It's considered the most common cause of autoimmune encephalitis after acute demyelinating encephalitis, and research describes it as predominantly affecting young adults and children with a clear female predominance. It's rare and was only characterized in the literature about fifteen years ago, so comprehensive prevalence data remain limited.

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Autoimmune encephalitis is a broad term for brain inflammation driven by the immune system, most often through antibodies against proteins on the surface of nerve cells or, less commonly, proteins inside them. Anti-NMDA receptor encephalitis is one specific and well-studied type, and others involve antibodies such as LGI1 or GABA receptors, with some cases linked to an underlying tumor and others not. The pattern of symptoms depends on which part of the brain is affected. Research describes autoimmune encephalitis overall as a group of conditions now recognized about as often as infectious causes of encephalitis, and their recognized prevalence has been rising as testing has improved, though reviewers note that solid population-level epidemiological data remain scarce. Some subtypes are more common in children and young adults and more prevalent in women, while others affect a broader age range.

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Hashimoto's encephalopathy, also called steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is a brain condition that occurs in some people who have elevated thyroid antibodies, especially anti-thyroid peroxidase (anti-TPO). Current understanding is that the exact mechanism isn't fully worked out, and the thyroid antibodies are thought to be a marker of a broader autoimmune process rather than a direct cause of the brain inflammation itself. Diagnosis rests on three things together: neurological symptoms after other causes are ruled out, elevated antithyroid antibodies, and meaningful improvement after immune-modulating treatment, which is also how the condition got its name, even though not everyone responds to steroids. Hashimoto's encephalopathy is rare, with one commonly cited estimate placing prevalence around 2.1 per 100,000 people, though data remain limited.

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Neuromyelitis optica spectrum disorder, historically called Devic's disease, is an autoimmune condition of the central nervous system that most often targets the optic nerves and spinal cord. In many people it's linked to antibodies against aquaporin-4, a water channel found on support cells called astrocytes, and the resulting injury leads to inflammation and demyelination distinct from multiple sclerosis. NMOSD is considered a rare condition whose prevalence varies notably by ancestry. Research describes prevalence at roughly 1 per 100,000 in people of European descent, higher, around 3.5 per 100,000, in East Asian populations, and higher still, up to around 10 per 100,000, in some Black populations. It carries a strong female predominance, with a female-to-male ratio reported as high as 9 to 1, and a typical age of onset around 40.

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MOG antibody disease is an autoimmune condition of the central nervous system associated with antibodies against myelin oligodendrocyte glycoprotein (MOG), a protein on the surface of myelin, the insulating coating around nerve fibers. It's now recognized as distinct from both multiple sclerosis and neuromyelitis optica spectrum disorder, though the three can look similar at onset. It can occur as a single event or take a relapsing course, and it often responds well to treatment, though individual attacks vary in severity. Research describes MOGAD as a rare condition, with worldwide prevalence estimated at roughly 1.3 to 2.5 per 100,000 people and annual incidence around 3.4 to 4.8 per million. Unlike many autoimmune neurological conditions, it doesn't show a strong sex difference, and about 30 percent of cases begin in childhood, with an average age of onset around 30.

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Balo concentric sclerosis is a rare demyelinating condition usually considered a variant of multiple sclerosis, marked by a distinctive pattern of alternating rings of damaged and preserved myelin that can resemble onion layers on MRI. As with MS, current understanding holds that the immune system attacks myelin, the insulating coating around nerve fibers, in the central nervous system. Its course ranges from a single attack to a relapsing or progressive pattern, and while it can advance rapidly over weeks to months, a number of documented cases show a more benign course with spontaneous improvement, particularly with early steroid treatment. This is a rare condition, described in the literature mainly through case reports and small case series rather than population studies, and no reliable prevalence or incidence figure exists in the research to date.

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Transverse myelitis is inflammation across a segment of the spinal cord that damages myelin and disrupts the signals traveling between the brain and the rest of the body. Current understanding describes it as an immune-mediated process causing spinal cord injury, often linked to a preceding infection or an underlying autoimmune disease, though many cases are idiopathic, meaning no clear trigger is found. Sometimes it stands alone, and sometimes it's the first sign of a broader condition such as multiple sclerosis, NMOSD, or MOGAD, so a diagnosis usually prompts a wider workup. Research describes the annual incidence of transverse myelitis in the United States at around 4.6 cases per million people, and more recent data suggest both the incidence and the tendency for it to affect women more than men may be higher than earlier estimates recognized.

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Stiff-person syndrome is a rare disorder of the central nervous system that causes progressive muscle rigidity and painful spasms, usually starting in the trunk and the muscles close to it. Most people with the classic form carry very high levels of antibodies against GAD65, an enzyme the body needs to make GABA, a calming signal in the nervous system, and researchers believe impaired GABA signaling leaves muscles overexcitable. A smaller share of cases are paraneoplastic, linked to an underlying cancer and antibodies such as amphiphysin. It is associated with other autoimmune conditions and can occur alongside type 1 diabetes. Stiff-person syndrome is considered rare, and research describes it as affecting roughly two-thirds women among autoimmune and paraneoplastic cases, with the paraneoplastic form most often tied to breast or lung cancer.

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Sydenham's chorea is a movement condition that follows infection with group A streptococcus, the bacteria behind strep throat, and is considered a major feature of rheumatic fever. The leading explanation is molecular mimicry, meaning antibodies made against the strep bacteria are thought to cross-react with the basal ganglia, the brain areas that help coordinate movement. It mostly affects children, with onset most often reported between ages seven and twelve, and is more frequent in girls. Research describes it as a major manifestation occurring in up to 40 percent of people with rheumatic fever, remaining uncommon in the United States while occurring more frequently in developing countries. The chorea often eases within six months in about half of cases, though it persists longer in others, and mood or attention changes frequently accompany the movement changes.

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Neuromyotonia, often called Isaacs syndrome, is a condition of overactive peripheral nerves that keep firing and make muscles contract when they should be at rest. Research describes it as an antibody-mediated channelopathy, meaning antibodies are thought to target voltage-gated potassium channels on peripheral nerves, suppressing the outward potassium current that normally keeps nerve firing in check and leaving the nerve hyperexcitable. Roughly half of cases show elevated antibodies against the voltage-gated potassium channel complex, such as CASPR2, though the antibody is not found in every case. Some cases are connected to a thymoma or other tumor, so evaluation typically includes cancer screening. Isaacs syndrome is considered rare, and because the evidence base is built mainly from case reports rather than population studies, a firm prevalence figure is not well established.

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Paraneoplastic cerebellar degeneration is a condition in which an immune response mounted against a cancer is thought to cross-react with the cerebellum, the part of the brain that coordinates movement and balance, damaging its Purkinje cells. Specific antineuronal antibodies, most often anti-Yo, are frequently found, and the condition is most associated with ovarian, breast, and lung cancers, along with Hodgkin lymphoma, sometimes appearing before the underlying cancer is diagnosed. It is considered one of the more commonly recognized paraneoplastic neurological syndromes, though still rare overall. Research estimates an age-standardized incidence of roughly 0.22 cases per 100,000 person-years. Onset is typically fairly rapid, unfolding over weeks, and can lead to significant unsteadiness and difficulty with coordination before it is recognized.

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Autoimmune autonomic ganglionopathy is a rare condition in which the immune system is thought to target the ganglionic acetylcholine receptor, a protein that helps relay signals at the autonomic ganglia, the relay stations for the nerve pathways that run automatic body functions like blood pressure, digestion, and pupil response. Antibodies against this receptor disrupt synaptic transmission in those ganglia and are found in roughly half of patients, with higher antibody levels generally associated with more severe symptoms. The result is a fairly rapid, often subacute onset of widespread autonomic failure that is usually monophasic, meaning it happens once, with some patients seeing partial improvement over months. The condition is considered rare enough that solid population-wide prevalence figures are not well established. A case series reported a median age at diagnosis around 45.

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Parsonage-Turner syndrome, also called neuralgic amyotrophy, is a sudden inflammation of nerves in the brachial plexus, the network that supplies the shoulder and arm. Researchers consider the underlying process to be immune-mediated, and pathogenesis is thought to be multifactorial, with several observations supporting an immune-triggering event, most often a preceding infection, though it can also follow vaccination, surgery, or physical stress. It is usually a single episode, though it can recur. Newer epidemiological research suggests the condition is substantially more common than once believed, with one large health-insurance-data study estimating an incidence of roughly 8 to 13 per 100,000 people per year, well above earlier estimates. In a series of over 300 patients the average age was in the early forties, with a majority male and a tendency to affect the right side.

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Small fiber neuropathy affects the smallest peripheral nerve fibers, the ones that carry pain and temperature sensation and help run automatic functions. It has many causes, most commonly diabetes, and up to about a third of cases remain idiopathic with no clear cause identified. A share of cases appear to be immune-related or occur alongside autoimmune conditions such as Sjogren's syndrome, and researchers are also identifying genetic contributors, including mutations in a sodium channel gene that make nerve fibers more excitable. Research estimates a prevalence around 53 cases per 100,000 people, though this figure likely undercounts milder or undiagnosed cases. Diagnosis typically relies on measuring nerve fiber density in a small skin biopsy, since standard nerve conduction studies often appear normal.

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Opsoclonus-myoclonus syndrome, sometimes called dancing eyes syndrome, is an extremely rare condition thought to be immune-mediated, marked by chaotic eye movements and muscle jerks. Researchers believe an immune process disrupts structures in the brainstem and cerebellum involved in controlling eye movement, though the precise mechanism is not fully worked out. In children it is often linked to a tumor called neuroblastoma; in adults roughly half of cases are paraneoplastic, most commonly tied to small-cell lung cancer or breast cancer, while the other half are idiopathic and often follow an infection. The condition is considered exceptionally rare, with research estimating an incidence around 0.2 cases per million children per year and adult incidence lower still. Because it is so uncommon, diagnosis can be difficult and is often made after other causes have been ruled out.

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Narcolepsy type 1 is autoimmune-related or suspected to be autoimmune. It involves the loss of brain cells in the hypothalamus that make hypocretin, also called orexin, a chemical that helps keep wakefulness and sleep stable. Research increasingly points to an immune process, with T cells thought to target and destroy hypocretin neurons in people with a particular genetic background. Nearly all people with narcolepsy type 1 carry the HLA-DQB1*06:02 gene variant, compared with about 20 to 25 percent of the general population, and rates of the condition have been observed to rise following certain infections, most notably H1N1 influenza, and after the Pandemrix influenza vaccine used in parts of Europe. Researchers describe the evidence for an autoimmune basis as strong, and note it is not fully settled, since a defining autoantigen has not been confirmed.

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Postural orthostatic tachycardia syndrome is autoimmune-related or suspected in a portion of cases. It is a form of dysautonomia in which the heart rate rises sharply on standing, typically by 30 beats per minute or more within ten minutes, without the normal accompanying drop in blood pressure. Researchers describe several overlapping subtypes, reflecting that POTS likely results from more than one underlying process. Several lines of research point to immune involvement in some people, including a higher rate of co-occurring autoimmune conditions and certain neural receptor antibodies, though no single causative antibody has been identified. POTS most often affects people between fifteen and forty-five, with a strong female predominance estimated around 80 percent of cases, and research estimates prevalence somewhere between 0.2 and 1.0 percent in developed countries.

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Myalgic encephalomyelitis, also called chronic fatigue syndrome, is autoimmune-related or suspected by some researchers, though its cause is not established. It is a complex, long-term illness affecting the nervous, immune, and energy-producing systems, often beginning after an infection. Immune dysregulation is one of several leading areas of research, and studies describe reduced natural killer cell activity, T-cell exhaustion, and diverse autoantibodies in many patients, together suggesting an autoimmune component without confirming one as the cause. Other research threads point to metabolic and neuroendocrine changes, and no single marker has been confirmed. ME/CFS mostly affects adults, with peak onset between twenty and forty-five and a female-to-male ratio near three to one. Prevalence estimates vary by study, from roughly 0.3 to just under 1 percent of the population.

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Rheumatoid arthritis is a chronic inflammatory condition that most often targets the joints, particularly the small joints of the hands and feet, causing pain, swelling, and progressive damage to cartilage and bone. Research describes RA as driven by autoreactive T cells, B cells, and inflammatory cytokines that sustain inflammation in the joint lining, and the condition can also involve the skin, eyes, heart, kidneys, and lungs as it progresses. RA affects an estimated 1 percent of the global population, though prevalence varies by region, and it is roughly 3 to 4 times more common in women than men.

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Lupus is a systemic autoimmune condition in which the immune system produces antibodies against components of the cell nucleus, leading to inflammation, immune complex deposition, and tissue damage that can affect nearly any organ system, including the skin, joints, kidneys, brain, and lungs. Lupus is markedly more common in women, with studies estimating anywhere from about 6 to 9 women affected for every 1 man, and both prevalence and severity vary by race and ethnicity, with higher rates reported among Black, Hispanic, and Asian populations in several studies.

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Discoid lupus erythematosus is a chronic form of cutaneous lupus in which the immune system is thought to target skin tissue, producing inflammation that leaves coin-shaped, scarring patches, most often on the scalp, face, and ears. It is the most common form of cutaneous lupus and can occur on its own or alongside systemic lupus erythematosus (SLE). A population-based surveillance study estimated the age- and sex-adjusted incidence of cutaneous lupus at roughly 4.2 per 100,000 people, similar to SLE itself, and found DLE affects women at a markedly higher rate than men and appears more common among Black patients. Research describes DLE as present in an estimated 12 to 15 percent of new SLE cases, and some people with DLE alone go on to develop the systemic form over time, though most cases stay limited to the skin.

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Sjogren's syndrome is an autoimmune condition in which lymphocytes, a type of immune cell, infiltrate the exocrine glands that produce tears and saliva, and this infiltration together with polyclonal B-cell activation and autoantibody production against Ro and La antigens is thought to drive the resulting glandular dysfunction. Over time this reduces the glands' ability to keep the eyes and mouth moist, and the same immune activity can extend to other tissues in some people. Sjogren's can occur alone or alongside another autoimmune condition such as rheumatoid arthritis or lupus. A systematic review and meta-analysis estimated that primary Sjogren's affects roughly 0.2 to 3.0 percent of the population, with a pooled incidence around 7 per 100,000 person-years, and research consistently finds it affects women far more often than men, at a ratio near 9 to 1.

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Systemic sclerosis is a condition in which the immune system and connective tissue interact in a way that leads to thickening and hardening of the skin, and in its systemic form, involvement of internal organs including the lungs, heart, kidneys, and digestive tract. Current understanding describes both an inflammatory autoimmune process and an overgrowth of collagen, the protein that gives connective tissue its structure, driving the fibrosis seen in affected organs. A 2023 analysis of global data estimated the worldwide incidence at roughly 8.6 per 100,000 person-years and prevalence around 19 per 100,000 people, translating to an estimated 1.47 million people affected globally, though rates vary widely by region and are notably higher in North America and Europe than in East Asia. Systemic sclerosis is markedly more common in women and typically diagnosed in mid-adulthood.

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CREST syndrome is the limited cutaneous subtype of systemic sclerosis, named for its classic features of calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia, though the full expression of all five is uncommon and tends to develop gradually. The same immune-driven fibrotic process seen in systemic sclerosis is at work, and it is associated with the anti-centromere antibody more often than the diffuse form. Skin involvement stays confined to the fingers, hands, and forearms, sometimes with the feet and lower legs, and cohort studies suggest limited cutaneous disease is the more common of the two systemic sclerosis subtypes. Research describes limited disease as generally following a more favorable course than diffuse systemic sclerosis, though it carries its own risk of pulmonary hypertension over time.

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Mixed connective tissue disease combines features of more than one connective tissue disease, often lupus, scleroderma, and inflammatory muscle disease, in the same person, and is distinguished from these separate conditions by a particular antibody pattern directed against U1-RNP. The immune system is thought to drive this overlapping process, and the clinical picture commonly includes Raynaud's phenomenon, swollen or puffy hands, joint pain, and swallowing difficulty, though the exact combination varies. A Norwegian national multicentre survey, one of the few population-based studies of this condition, estimated the point prevalence of adult-onset MCTD at about 3.8 per 100,000 people and the annual incidence at roughly 2.1 per million, figures that support its reputation as the least common of the connective tissue diseases. Estimates vary across populations and diagnostic criteria.

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Undifferentiated connective tissue disease describes a pattern in which someone has clinical signs and autoantibodies pointing to a systemic autoimmune process, and the picture does not fit the full classification criteria for a named condition such as lupus, scleroderma, or Sjogren's. The immune involvement is considered real even though it remains in this in-between category for many people. A seven-center cross-sectional study of 184 patients found the most common features were joint pain, present in about two-thirds, followed by arthritis, Raynaud's phenomenon, and dry eyes or mouth, generally milder than in the fully defined conditions it resembles. Follow-up research suggests a meaningful share of people with UCTD go on to develop a defined connective tissue disease such as lupus within several years, while many others remain stable.

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Ankylosing spondylitis is a form of inflammatory arthritis that mainly affects the spine and the sacroiliac joints where the spine meets the pelvis, part of a larger group of conditions called axial spondyloarthritis. Current understanding points to immune cells and inflammatory cytokines, particularly along the interleukin-23/17 pathway, driving inflammation at the spine and at the entheses, the points where ligaments and tendons attach to bone, which over time can lead to stiffening and, in some people, fusion of parts of the spine. The HLA-B27 gene is strongly associated with the condition, present in a large majority of people diagnosed, though having the gene alone does not mean someone develops AS. Reported prevalence varies considerably across populations, and research describes a male predominance in classic AS, with onset almost always before age 50.

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Psoriatic arthritis is a form of inflammatory arthritis that develops in a meaningful share of people who have psoriasis, most often appearing after skin symptoms but occasionally before them. It causes joint pain, stiffness, and swelling, along with characteristic features like sausage-like swelling of entire fingers or toes (dactylitis) and inflammation where tendons attach to bone (enthesitis). Research estimates it complicates psoriasis in roughly 6 to 41 percent of cases depending on the population studied, and left untreated it can cause irreversible joint damage.

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Reactive arthritis is a form of joint inflammation triggered by an infection elsewhere in the body, often in the gut, urinary tract, or genital tract, where the immune response set off by the infection is thought to end up inflaming the joints, sometimes through bacterial antigens or genetic material detected within the joint itself. It usually begins days to weeks after the triggering infection and most often affects the lower-extremity joints, and in many people it settles over months, though it can recur or become chronic. Reactive arthritis is considered part of the broader spondyloarthritis family and is strongly associated with the HLA-B27 gene. Research describes a worldwide prevalence estimated around 40 per 100,000 people, and certain triggering infections such as Campylobacter are estimated to lead to reactive arthritis in roughly 1 to 5 percent of those infected.

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Juvenile idiopathic arthritis is the most common form of chronic arthritis in childhood, in which the immune system is understood to drive persistent joint inflammation in a child under 16, with several subtypes that behave differently and a cause that is not fully understood. A systematic review found incidence estimates ranging from roughly 2 to 23 per 100,000 children per year and prevalence ranging just as widely, from under 4 to as high as 400 per 100,000, a spread researchers attribute to differences in study methods and classification systems across regions. More recent UK population data found an incidence around 5.6 per 100,000 and prevalence around 43.5 per 100,000, and research consistently finds JIA affects girls more often than boys. Depending on the subtype, some children also develop silent eye inflammation that requires ongoing monitoring.

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Adult-onset Still's disease is a rare systemic inflammatory condition, considered part of the autoinflammatory and autoimmune spectrum, that produces spiking fevers, an evanescent salmon-colored rash, and joint inflammation, often alongside an elevated white blood cell count. Current understanding describes its pathogenesis as involving genetic background and infectious triggers that activate macrophages and neutrophils, with cytokines including interleukin-1, interleukin-6, interleukin-18, and TNF-alpha driving the inflammatory episodes. Because it is uncommon, solid prevalence figures are limited and estimates vary between reports, so a precise figure is not given here. The disease can follow a single self-limited episode, a relapsing pattern, or a persistent joint-centered course, and macrophage activation syndrome, a severe complication, is reported in up to 15 percent of cases.

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Polymyalgia rheumatica affects the muscles and connective tissue around the shoulders, neck, and hips, mainly in older adults. Research describes inflammation of the synovium and periarticular structures, with systemic IL-6 signaling thought to drive much of the aching, stiffness, and fatigue that mark the condition, though the exact trigger is not fully understood. It is considered the most common inflammatory rheumatic disease in people over 50, and studies describe incidence estimates that vary widely by region, from roughly 13 per 100,000 in southern Europe to well over 100 per 100,000 in parts of Scandinavia. It is two to three times more common in women, and it sometimes occurs alongside a related blood-vessel inflammation called giant cell arteritis, which is why the two conditions are often studied and monitored together.

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Relapsing polychondritis is a rare condition in which the immune system appears to target cartilage in the ears, nose, joints, and airways, along with other proteoglycan-rich tissues such as the eyes, heart, and blood vessels. Research describes it as episodic and progressive, with recurring bouts of inflammation that can, over time, affect the structural integrity of the cartilage involved, and the underlying mechanism is understood to involve an autoimmune response though the exact trigger remains unclear. Because it is rare, solid population-wide prevalence figures are hard to pin down, and studies note that a concurrent autoimmune disease, often thyroid-related or rheumatic, is present in roughly a third of people diagnosed. It occurs in men and women in roughly equal numbers, with onset most often in the fourth decade of life.

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Palindromic rheumatism produces sudden, short-lived episodes of joint inflammation that resolve completely between attacks, and research links the condition to the same autoantibodies seen in rheumatoid arthritis, including rheumatoid factor and anti-citrullinated protein antibodies, thought to provoke joint inflammation during flares. A population-based study from South Korea estimated the incidence at roughly 7 per 100,000 person-years, occurring at similar rates in men and women, with onset typically in a person's late forties. Research describes it as more common than once believed, and it sits on a spectrum with rheumatoid arthritis. Studies following people over time have found that a meaningful share, in some cohorts around two-thirds, eventually develop chronic arthritis, most often rheumatoid arthritis, while others experience only the episodic pattern for years.

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Dermatomyositis is an inflammatory disease in which the immune system is understood to target small blood vessels supplying the muscles and skin, producing muscle weakness alongside a distinctive rash. Research describes the process as involving both adaptive immune activity, including autoantibodies directed at specific proteins involved in cell processes, and innate immune pathways, with the contribution of each varying between individuals. It is a rare condition that can appear at any age, and studies describe two peaks of onset, one in childhood between roughly 5 and 15 years and another in adulthood between 40 and 60, with women affected more often than men. Dermatomyositis has also been associated with an increased likelihood of underlying malignancy in adults, so current guidance calls for cancer screening at diagnosis.

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Polymyositis is an inflammatory muscle disease in which the immune system is understood to directly target muscle fibers, producing weakness without the skin rash that distinguishes dermatomyositis. Research describes the process as involving immune cells, particularly CD8 T-cells, infiltrating and damaging muscle tissue from within, most often affecting the muscles closest to the trunk. Polymyositis and dermatomyositis are frequently studied together because they share many features and differ mainly in histopathology and skin involvement, and both are considered rare, serious conditions. Epidemiological studies describe a female predominance, with one Japanese cohort reporting a female-to-male ratio of roughly 2.7 to 1, and onset most often in mid-adulthood, though reported rates vary by population and diagnostic criteria used.

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Inclusion body myositis combines inflammation with a slower, degenerative process inside muscle fibers, and research describes findings such as abnormal accumulations of amyloid-beta and phosphorylated tau protein within muscle cells, thought to contribute to cellular stress and progressive fiber damage alongside immune-cell involvement. It is the most common inflammatory muscle disease diagnosed after age 50, and a large population-based study estimated its point prevalence at roughly 3.3 per 100,000 people, more common in men than women at about a 3-to-2 ratio, with an average age at diagnosis around 67. Diagnosis is often delayed by more than five years on average, and the condition tends to progress gradually and respond less consistently to the anti-inflammatory treatments that help other inflammatory myopathies.

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Immune-mediated necrotizing myopathy is a muscle disease in which the immune system is understood to drive the death of muscle fibers directly, with research describing deposits of immune complement proteins on damaged muscle cells and, in many cases, relatively little of the lymphocyte infiltration seen in other inflammatory myopathies. Two autoantibodies, anti-SRP and anti-HMGCR, are associated with distinct forms of the condition and help define its diagnosis, though some people test negative for both. Contemporary research estimates it affects roughly 7 to 11 people per 100,000 annually in the United States, making it rare, and it typically produces more rapidly progressive weakness and higher muscle enzyme levels than related conditions. The disease process is only partly understood, and researchers are still working out why some cases respond better to treatment than others.

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Antisynthetase syndrome is defined by a group of antibodies directed at aminoacyl-tRNA synthetases, enzymes that play a role in building proteins inside cells, though research notes that exactly how these antibodies contribute to the disease process is still undetermined. The condition typically combines muscle inflammation, joint pain, and interstitial lung disease, and studies describe genetic predisposition and possible viral triggers as contributing factors, without a single confirmed cause. Because antisynthetase syndrome was only recently distinguished as its own diagnostic category, population-based epidemiology is still limited, and researchers are actively working to establish reliable incidence figures. Research describes the lung involvement as a major driver of prognosis, often making the overall outlook more serious than for muscle inflammation alone.

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Eosinophilic fasciitis is a rare condition in which a type of white blood cell called eosinophils is understood to interact with fibroblasts, the cells that build connective tissue, triggering signaling molecules that thicken and inflame the fascia beneath the skin. Research describes the exact trigger as unknown, though many people report unusually strenuous exercise in the one to two weeks before symptoms begin. Because it is rare, precise population prevalence has not been well established, though case series describe an average age at onset in the mid-forties with roughly equal numbers of men and women affected, and a coexisting autoimmune condition is present in some patients. Blood testing often shows elevated eosinophils, and the condition can resemble scleroderma in how the tissue tightens, though it typically spares the fingers.

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Fibromyalgia is included here as autoimmune-related or suspected rather than a confirmed autoimmune disease, and it frequently occurs alongside autoimmune conditions such as lupus, rheumatoid arthritis, and Sjogren's, which is part of why it appears in this group. Research describes the primary driver as central sensitization, a change in how the nervous system processes pain signals that turns up sensitivity throughout the body, alongside possible contributions from peripheral nerve signaling and immune pathways still being studied. It is understood to be the third most common musculoskeletal condition after lower back pain and osteoarthritis, and research estimates worldwide prevalence at roughly 2 to 3 percent of the population, though figures vary by diagnostic criteria used. It is substantially more common in women and most often diagnosed in the thirties.

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Psoriasis is a chronic skin condition driven by dysregulated interaction between the innate and adaptive immune systems. Immune cells release cytokines, including TNF-alpha, IL-17, and IL-23, that drive skin cells to multiply far faster than normal, producing the thick, scaled plaques characteristic of the condition. Psoriasis affects an estimated 2 to 4 percent of the population, roughly 125 million people worldwide, and can appear at any age, though it most often first appears in early adulthood.

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Vitiligo affects the skin and, in some cases, the hair. The immune system is thought to attack and destroy melanocytes, the cells that produce the pigment melanin, and as those cells are lost the skin develops smooth patches without color. The autoimmune theory is the most widely accepted explanation, and researchers describe a process in which melanocyte stress and dysfunction help trigger the immune response that ultimately destroys them, with newer research pointing to type I interferon and JAK/STAT signaling as part of that pathway. Vitiligo is estimated to affect roughly 0.5 to 2 percent of people worldwide, with most reviews citing a figure near 1 percent, and it can begin at any age. People with vitiligo are also more likely to have other immune-mediated conditions, thyroid disease among the most common, so clinicians often screen for related conditions once vitiligo is diagnosed.

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Alopecia areata affects the hair follicles. Research describes the condition as resulting from a loss of the hair follicle's normal immune privilege, allowing T cells to mistakenly target the follicle and interrupt the hair growth cycle. Because the follicle itself is usually not destroyed, hair can regrow once the inflammatory attack quiets, which distinguishes alopecia areata from scarring forms of hair loss. Genetic susceptibility combines with environmental triggers to bring on episodes, and the condition often runs in families or alongside other autoimmune conditions, most commonly autoimmune thyroid disease. Reviews describe a lifetime prevalence of roughly 2 percent of the general population worldwide, though estimates vary by region and are notably higher in North African, Middle Eastern, and North American populations than in parts of Asia and Western Europe.

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Bullous pemphigoid affects the skin, most often in older adults. The immune system produces antibodies against BP180 and BP230, two proteins that help anchor the outer layer of skin to the layer beneath it, and most patients' antibodies target a specific region of BP180 called the NC16A domain. As that anchoring breaks down, fluid separates the skin layers and forms tense blisters, with complement activation and the buildup of eosinophils and neutrophils driving much of the surrounding inflammation. Research also points to a type 2 immune signature in many cases, including elevated IgE and eosinophil activity in the affected skin. Bullous pemphigoid is described as the most common subepidermal blistering disease, though it remains uncommon overall, with global incidence estimated at well under one new case per 1,000 person-years, concentrated heavily in people over 70.

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Pemphigus vulgaris affects the skin and mucous membranes. The immune system makes IgG antibodies against desmoglein 3 and, in many cases, desmoglein 1, proteins that hold epidermal cells together at structures called desmosomes. When those antibodies bind their targets, cell-to-cell adhesion breaks down, a process called acantholysis, and cells separate to form fragile blisters that erode easily. The condition is closely linked to specific HLA class II gene variants, which helps explain why it clusters in certain families and populations, and it tends to appear between the third and sixth decades of life. Pemphigus vulgaris is considered a rare disease, and research also describes a notable association with thyroid disease and type 1 diabetes in affected people and their relatives, though a precise worldwide prevalence figure is not well established in the literature.

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Pemphigus foliaceus affects the skin. The immune system produces IgG antibodies, largely IgG4, against desmoglein 1, a protein that holds together cells in the upper layers of the epidermis, and T cells specific to desmoglein 1 are found in most people with the condition. Because desmoglein 1 sits closer to the skin's surface and desmoglein 3 remains intact in the deeper mucosal layers, blistering in pemphigus foliaceus stays superficial and the mouth is typically spared, unlike pemphigus vulgaris. The exact trigger is not well understood, and research describes a mix of genetic susceptibility, environmental exposures, and immune dysregulation behind its development. Pemphigus foliaceus is rare, and an endemic form called fogo selvagem occurs in specific regions of Brazil and other parts of Latin America, where environmental factors are believed to play a larger role.

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Dermatitis herpetiformis is considered the skin manifestation of celiac disease. In people with a genetic susceptibility to gluten, eating gluten triggers autoantibodies against tissue transglutaminase, and in the skin specifically against a related enzyme, transglutaminase 3, now understood as the primary target driving the rash. These antibodies deposit in the skin and set off an intensely itchy, blistering reaction, most often on the elbows, knees, buttocks, and scalp. Most people with dermatitis herpetiformis also have the intestinal changes of celiac disease, including inflammation and sometimes villous atrophy, even when they have few or no digestive symptoms. Research describes dermatitis herpetiformis as substantially less common than celiac disease itself, with studies from Finland and the United Kingdom estimating roughly one case of dermatitis herpetiformis for every eight cases of celiac disease.

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Lichen planus is a T-cell-mediated condition that can affect the skin, mouth, genitals, scalp, and nails. Research describes cytotoxic CD8-positive T cells attacking keratinocytes, the main cells of the outer skin layer, in response to a self-antigen that has not been clearly identified, while CD4-positive T cells also contribute to the surrounding inflammation. The trigger appears to be multifactorial, with genetics, certain infections, medications, and immune dysregulation all playing a role, and lichen planus is sometimes seen alongside other autoimmune conditions. The oral form most often affects women between 30 and 60, and skin lesions frequently clear on their own within one to two years, though recurrences are common and can leave lasting discoloration. A precise overall prevalence figure is not well established, though it is generally described as an uncommon condition affecting roughly 1 percent or less of the population.

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Lichen sclerosus is a chronic inflammatory condition that most often affects the genital and anal skin. Current research points to an immune-driven Th1 response, in which environmental factors acting on a genetically susceptible person set off a chronic inflammatory state that damages tissue and activates pathways involved in collagen buildup, ultimately leading to the thinned, fragile, whitened skin that characterizes the condition. Older hypotheses also considered infectious triggers and a reaction to prior skin trauma, and it is likely that more than one mechanism contributes across different people. Lichen sclerosus most often develops in postmenopausal women, though it can affect men and children too, with children accounting for an estimated 7 to 15 percent of cases. Estimates of how common it is range from roughly 1 in 300 to 1 in 1,000 people, and because it is under-recognized, the true prevalence may be higher.

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Morphea, also called localized scleroderma, affects the skin and sometimes the tissue just beneath it. Research describes a profibrotic inflammatory process in which transforming growth factor-beta and an imbalance among T-lymphocyte subtypes drive an overproduction of collagen, causing patches of skin to thicken and harden. The exact trigger remains unknown, and researchers describe a mix of genetic, immune, and occasionally environmental factors, such as exposure to certain chemicals, that may contribute in susceptible people. Unlike systemic scleroderma, morphea generally spares the internal organs and stays confined to the skin, fascia, and sometimes underlying muscle or bone, particularly in the juvenile form, which tends to relapse more often. Morphea is described in the literature as a rare condition, though a single, well-established worldwide prevalence figure was not identified in this search.

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Cutaneous lupus erythematosus affects the skin and can occur alone or alongside systemic lupus. Research describes ultraviolet light as a key environmental trigger, setting off apoptosis in skin cells that exposes self-antigens and prompts native skin cells, along with innate and adaptive immune cells including Th1 and Th17 cells, cytotoxic T cells, and dendritic cells, to drive and sustain the inflammatory rash. Genetic and immunological factors also shape who develops the condition and which of its several forms, including discoid, subacute, and acute cutaneous lupus, they experience. Cutaneous lupus is more evenly split between men and women than systemic lupus and tends to appear somewhat later in life, and research describes its overall incidence as roughly similar to that of systemic lupus, with a notably higher prevalence among Black patients in the studies reviewed.

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Chronic spontaneous urticaria causes recurring hives and itching without an identifiable outside trigger, lasting more than six weeks. Mast cells sit at the center of the current understanding of this condition. When activated, they release histamine and other mediators that cause blood vessels to leak fluid into the skin, producing raised, itchy welts and sometimes the deeper swelling known as angioedema. Research describes an autoimmune subset in which the body produces functional autoantibodies against IgE or its high-affinity receptor on mast cells, found in roughly 40 percent of patients studied, which helps explain resistance to standard antihistamine treatment in some cases. Other immune cells, including T cells and eosinophils, are also understood to help sustain the reaction. A precise general-population prevalence figure was not identified in this search, though the condition is understood to affect a meaningful minority of people who experience chronic hives.

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Linear IgA bullous dermatosis is a rare condition in which IgA autoantibodies target proteins in the basement membrane zone, the layer that anchors skin to the tissue beneath it, producing tense blisters that can form ring-like or clustered patterns. Research describes a bimodal pattern of onset affecting both children and adults, with somewhat different typical locations for the rash in each group, and certain HLA gene variants appear more often in people who develop it. The condition can arise on its own or be triggered by certain medications, particularly some antibiotics, in which case it often resolves once the medication is stopped. It has also been linked in some studies to inflammatory bowel disease and, less commonly, to certain cancers. Linear IgA bullous dermatosis is genuinely rare, and this search did not turn up a reliable, well-established prevalence figure in the literature, so no percentage is given here.

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Epidermolysis bullosa acquisita affects the skin and, in some cases, mucous membranes. The immune system produces autoantibodies against type VII collagen, the main component of the anchoring fibrils that connect the epidermis to the layer of skin beneath it, and animal studies have shown that these antibodies alone are enough to reproduce the blistering disease, confirming their role in causing it. As the anchoring breaks down, the skin becomes fragile and blisters, especially in areas exposed to friction or minor trauma, and healing often leaves scarring and small white bumps called milia. A less common inflammatory subtype also exists, with more widespread blistering and visible inflammation. Epidermolysis bullosa acquisita is a genuinely rare condition, with research estimating an incidence of roughly 0.2 new cases per million people per year, making it one of the rarest of the autoimmune blistering diseases.

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Hidradenitis suppurativa is a chronic inflammatory skin condition, autoimmune-related rather than a classic antibody-driven autoimmune disease, that affects hair follicles in areas with a concentration of apocrine sweat glands. Research describes a process of hair follicle blockage and hyperkeratinization that leads to follicle rupture, triggering an inflammatory response involving TNF-alpha and interleukin-17 signaling that produces the deep-seated nodules, abscesses, and draining tunnels characteristic of the condition. A genetic predisposition combines with environmental factors, and the underlying inflammation is now understood to extend beyond the immediate lesions. Hidradenitis suppurativa most often begins in young adults between 18 and 34, and studies estimate it affects roughly 1 to 2 percent of the population, though researchers note it is likely under-reported given variation in diagnosis and awareness across regions.

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Atopic dermatitis, the most common form of eczema, is a chronic inflammatory skin condition, immune-related rather than a classic antibody-driven autoimmune disease, that arises from a combination of skin barrier dysfunction and immune dysregulation. Research describes genetic factors, including mutations in the filaggrin gene, that weaken the skin's ability to hold moisture and keep out irritants and allergens, allowing immune cells in the skin to encounter triggers more easily and mount an inflammatory response. This impaired barrier is now understood as an early step that can set off a broader pattern of allergic sensitization sometimes called the atopic march. Atopic dermatitis is described in the literature as the most common chronic inflammatory skin disease, typically appearing in early childhood and often improving with age, though it can persist into or begin in adulthood, and its prevalence and severity vary with age, geography, and socioeconomic factors.

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Mucous membrane pemphigoid, also called cicatricial pemphigoid, is a rare chronic autoimmune blistering condition in which antibodies and complement deposit along the basement membrane of mucous membranes and sometimes the skin. Research describes this immune activity as driving blistering, erosions, and, over time, fibrosis and scarring in affected tissue, which is where the name 'cicatricial' comes from. The eyes and mouth are the most frequently affected sites, involved in an estimated 85 and 65 percent of cases respectively, followed less often by the nose, throat, genitals, and esophagus. Scarring in the eyes and airway is the most serious long-term concern, and research describes roughly half of patients developing esophageal or ocular scarring severe enough to cause narrowing or vision loss if the disease is not controlled. Mucous membrane pemphigoid typically begins in later adulthood and is considered a rare disease overall.

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Autoimmune hemolytic anemia affects the red blood cells. The immune system is thought to produce autoantibodies that attach to a person's own red blood cells and mark them for early destruction, a process called hemolysis, faster than the bone marrow can replace them. Warm AIHA, in which the antibodies react best at body temperature, accounts for over two-thirds of cases and is the most common form, and it can occur on its own or alongside another condition such as lupus. AIHA is rare, with research describing a prevalence in the range of roughly 4 to 20 cases per 100,000 people depending on the population studied, and it becomes more common with age and occurs more often in women than men. Severity varies widely, and the destruction of red blood cells can happen gradually or quite quickly, which is part of why ongoing monitoring matters.

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Cold agglutinin disease is a form of autoimmune hemolytic anemia in which the immune system produces antibodies, usually of the IgM type, that become active at cooler temperatures and attach to red blood cells in the smaller blood vessels near the body's surface. This binding activates part of the immune system called the complement pathway, and the affected red blood cells are broken down faster than the body can replace them. CAD is rare and research describes a prevalence estimated around 1 to 3 cases per 100,000 people in the United States, with cold climates associated with higher rates than warmer ones. It tends to appear later in life, around the mid-sixties on average, and is more common in women, and exposure to cold typically brings on or worsens symptoms.

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Immune thrombocytopenia affects platelets, the cell fragments that help blood clot. The condition involves a misdirected immune response in which antiplatelet antibodies and immune cells clear platelets from circulation faster than normal, and current understanding also points to impaired platelet production in the bone marrow as a contributing factor rather than destruction alone. It can follow an infection, occur on its own, or appear alongside other autoimmune conditions. ITP is uncommon and research estimates its prevalence at roughly 9 to 20 cases per 100,000 people, with incidence rising with age and a modest tendency to affect women somewhat more than men. Severity ranges widely, and many people with only mildly low platelet counts have few or no symptoms, while others experience more significant bleeding risk.

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Thrombotic thrombocytopenic purpura is a rare and serious condition in which small clots form throughout the small blood vessels of the body, using up platelets and damaging red blood cells as they pass through narrowed vessels. The acquired, immune-mediated form is driven by autoantibodies against ADAMTS13, an enzyme that normally helps regulate a clotting protein called von Willebrand factor, leaving that regulation severely impaired. Research describes an incidence for the immune-mediated form of roughly 1.8 to 4 cases per million people per year, making it one of the rarer conditions in this category. Because clots can form quickly and affect organs including the brain and kidneys, TTP is treated as a medical emergency requiring urgent, specialist-led care rather than a condition to monitor and wait on.

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Antiphospholipid syndrome is a condition in which the immune system produces antibodies, most importantly against a protein called beta-2 glycoprotein I, that appear to increase the tendency of blood to clot and to disrupt normal placental function during pregnancy. Current understanding describes a broader process of thrombo-inflammation behind the clotting risk, involving activation of platelets, blood vessel lining cells, and the complement system. APS can occur on its own or alongside another autoimmune condition such as lupus. Research describes it as an uncommon condition, with studies estimating incidence and prevalence in the general population at roughly 1 to 2 new cases and 40 to 50 existing cases per 100,000 people, while antiphospholipid antibodies themselves are found more often, in a meaningful share of people with unexplained pregnancy loss, stroke, or blood clots.

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In autoimmune aplastic anemia, the immune system is understood to mount a T-cell mediated attack against the stem cells in bone marrow that normally give rise to red cells, white cells, and platelets, so the marrow becomes underactive and produces too few of all three blood cell lines. Cytotoxic T-cells release inflammatory signals that suppress this production and drive the cells toward early cell death, leaving the body short across the board rather than in just one blood cell type. The condition is uncommon, with research describing an incidence of roughly 2 cases per million people per year in Western populations and a rate about two to three times higher in parts of Asia. It can occur at any age and shows two peaks, affecting younger people between about 10 and 25 and, separately, adults over 60.

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Giant cell arteritis is inflammation of medium and large arteries, often those around the head and scalp, in which immune cells including T-cells and macrophages gather in the artery wall and form clusters called granulomas that can narrow the vessel and reduce blood flow. It mainly affects people over fifty, and a global meta-analysis estimated a pooled incidence of roughly 10 cases per 100,000 people over fifty and a pooled prevalence of roughly 52 per 100,000, with rates highest in Scandinavian countries at around 22 per 100,000. It is more common in women, with studies describing a female-to-male ratio near 1.7 to 1. It often overlaps with polymyalgia rheumatica, which brings shoulder and hip stiffness, and because it can threaten vision, it is treated as a medical emergency with urgent, specialist-led care.

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Takayasu arteritis is a chronic, granulomatous inflammation of the aorta and its major branches, in which immune cells infiltrate and damage the vessel wall over time, which can narrow, weaken, or scar these large arteries. It is considered a rare condition, with research describing an incidence of roughly 1 to 2 cases per million people and a prevalence that varies notably by region, from about 5 to 33 cases per million in Western Europe to a higher 30 to 40 cases per million in parts of Asia. It tends to affect younger adults, especially women of childbearing age, and most often begins during the second or third decade of life. Early symptoms are often vague, such as fatigue and low-grade fever, before more specific vascular symptoms appear as blood flow through affected arteries becomes restricted.

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Polyarteritis nodosa is inflammation of medium-sized, and sometimes small, arteries, in which the immune system appears to attack vessel walls in a pattern of necrotizing vasculitis that can reduce blood flow to the tissues those arteries supply. Unlike some related vasculitis conditions, PAN typically does not involve ANCA antibodies or granuloma formation, and it preferentially affects the skin, peripheral nerves, and gastrointestinal tract. It is rare, with a French population study estimating prevalence at roughly 31 cases per million adults, and that same research found the condition about twice as common in people of European ancestry. Cases were once frequently linked to hepatitis B infection, and while that association has declined substantially as hepatitis B rates have fallen, current research increasingly explores genetic and other contributing factors.

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Microscopic polyangiitis is inflammation of small blood vessels, in which the immune system appears to attack vessel walls with little or no immune complex deposition, a pattern researchers call pauci-immune vasculitis. It is one of the ANCA-associated vasculitides, and the antibodies involved are most often directed against an enzyme called myeloperoxidase, though a smaller share of people test positive for a different target, proteinase 3, and not everyone with MPA has detectable ANCA. Research describes the ANCA-associated vasculitides as a group having a pooled global incidence of roughly 17 cases per million people per year and a pooled prevalence near 198 cases per million, and within that group MPA tends to affect men somewhat more than women and typically appears after age fifty. The kidneys and lungs are most often involved and tend to drive the course of the condition.

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Granulomatosis with polyangiitis (GPA) is inflammation of small and medium blood vessels with clusters of inflammatory tissue called granulomas, in which the immune system appears to attack the vessels and surrounding tissue. It is the most common of the ANCA-associated vasculitides, a group of conditions linked to antineutrophil cytoplasmic antibodies, and most people with GPA test positive for the PR3-ANCA antibody. It commonly affects the sinuses, nose, lungs, and kidneys, and can involve other organs as the inflammation spreads. GPA is considered a rare disease, and estimated incidence varies by country, from roughly 10 to 12 cases per million person-years in the United States and United Kingdom to lower rates elsewhere. A large United States claims-database analysis found an incidence of about 12.8 cases per million person-years in working-age adults and 1.8 per million in children, and it can occur at any age, with some studies describing a slight female predominance.

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Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare inflammation of small blood vessels marked by high numbers of a white blood cell called the eosinophil, in which the immune system appears to attack the vessels and surrounding tissues. Research describes the disease as typically unfolding in phases, starting with adult-onset asthma and allergic rhinosinusitis that can precede the vasculitic phase by years, followed by tissue eosinophilia and then the vasculitic phase, when vessel inflammation can affect the lungs, skin, heart, nerves, gut, and kidneys. Only about a third of people with EGPA test positive for ANCA antibodies, and their presence appears to mark a different clinical pattern than ANCA-negative disease. EGPA is one of the rarest ANCA-associated vasculitides, and while a precise population-wide prevalence figure is not well established, it is understood to be markedly less common than granulomatosis with polyangiitis, and it tends to appear in the third or fourth decade of life in people with a history of asthma or allergic disease.

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Behcet's disease is a chronic, relapsing condition involving inflammation of blood vessels of varying sizes, in which the immune system appears to drive recurring inflammation in different parts of the body, most often the mouth, skin, eyes, and joints. Its cause is not fully understood and current research describes a combination of genetic susceptibility, with the HLA-B51 gene the strongest known risk factor, and environmental triggers such as certain infections that together appear to prompt an overactive immune response. Behcet's disease is markedly more common along the historic Silk Route through the Middle East and East Asia, with estimated prevalence as high as several hundred per 100,000 people in Turkey, and far less common in Western countries such as the United Kingdom, where it affects fewer than 1 per 100,000. Onset usually occurs in the third or fourth decade of life, and men and women are affected in roughly equal numbers, though the pattern and severity of symptoms can differ between the sexes and by region.

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IgA vasculitis, formerly called Henoch-Schonlein purpura, is inflammation of small blood vessels driven by deposits of an antibody called IgA, in which the immune system appears to involve these vessels in the skin, joints, gut, and kidneys. Current research describes the underlying process as beginning with an abnormally structured form of IgA1 that the body has trouble clearing, which then forms immune complexes that deposit in small vessels and trigger local inflammation and tissue injury. It is described as the most common systemic vasculitis in children, frequently appearing after an upper respiratory infection and often resolving on its own, though it can also occur in adults, in whom the disease tends to run a more severe course. Precise population-wide prevalence figures are limited and vary by region and by how cases are counted, and research notes that incidence appears to be genetically and environmentally influenced, with cases clustering somewhat more often in the autumn and winter months.

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Kawasaki disease is inflammation of blood vessels that mainly affects young children, in which the immune system appears to mount an intense response, thought to be triggered by an as yet unidentified infectious agent, producing widespread vessel inflammation that can involve the arteries supplying the heart. It has been diagnosed in more than 60 countries across Asia, Europe, the Middle East, the Americas, and Africa, and research describes it as the leading cause of acquired heart disease in children in the United States and other developed countries. Incidence is markedly higher in Japan and in children of Japanese and other East Asian ancestry, with rates reported around 200 to 300 per 100,000 children under five, compared with a lower incidence, generally under 25 per 100,000, in the United States and Europe. It is a medical emergency because of the risk of coronary artery damage, which research indicates can develop in untreated cases, so care is urgent and specialist-led.

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Cryoglobulinemic vasculitis is inflammation of small and medium blood vessels caused by proteins called cryoglobulins that clump together in the cold, in which the immune system appears to involve these proteins in damaging the vessel walls, most often in the skin, joints, kidneys, and peripheral nerves. Research describes hepatitis C virus infection as the trigger in the large majority of cases, thought to prompt sustained overactivity of certain antibody-producing B cells that leads to the production of these abnormal proteins, while a smaller share of cases are linked to other autoimmune or blood conditions or occur without an identified cause. Cryoglobulinemia as a whole is considered a rare condition, with research describing prevalence under roughly 5 per 10,000 people in Western countries, and the vasculitis form, which involves active vessel inflammation and organ damage, represents a smaller subset of people who test positive for circulating cryoglobulins.

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Raynaud's phenomenon is an exaggerated narrowing of small blood vessels in the fingers and toes in response to cold or stress, which briefly limits blood flow. The primary form occurs on its own and research describes its underlying mechanism as still not fully understood despite more than a century of study, involving some combination of changes in blood vessel lining, nerve signaling, and locally produced substances that affect how vessels constrict and relax. Research estimates the pooled prevalence of primary Raynaud's phenomenon at roughly 5 percent of the general population, with figures in individual studies ranging from about 3 to 9 percent depending on how the condition is defined and diagnosed. The secondary form is autoimmune-related and can accompany conditions such as scleroderma or lupus, so it is marked here as related rather than as a primary autoimmune condition in its own right, and it tends to be more severe than the primary form.

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Rheumatic fever is an inflammatory condition that can follow a strep throat infection, in which the immune system, while responding to the infection, appears to also react against the body's own tissues such as the heart, joints, skin, and brain. Current research describes the underlying mechanism as molecular mimicry, in which antibodies made against components of the group A streptococcus bacteria cross-react with similar-looking proteins in a person's own heart and other tissues, typically producing symptoms two to four weeks after the initial infection. It is autoimmune-related and is marked here as related, and research estimates roughly 470,000 new cases occur worldwide each year, with the disease burden concentrated in developing countries where access to prompt treatment for strep infections is more limited. It is most common in children and can lead to lasting heart valve damage, known as rheumatic heart disease, which research links to several hundred thousand deaths globally each year.

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Goodpasture syndrome, also called anti-glomerular basement membrane (anti-GBM) disease, is a rare condition in which the immune system makes antibodies against a structural protein called type IV collagen found in the basement membrane lining the lungs and kidneys, leading to inflammation and damage in both. Research describes the disease as arising in genetically predisposed people, with a variety of environmental factors, including certain viral infections, proposed as possible triggers, though evidence for any single cause remains limited. It is considered rare, with research estimating an incidence of roughly one case per million people per year, and it accounts for an estimated one in five cases of a serious kidney condition called rapidly progressive glomerulonephritis. It can damage the kidneys quickly and cause bleeding in the lungs, so care is urgent and specialist-led, and research notes that early diagnosis and prompt treatment with immunosuppression and plasma exchange have meaningfully improved outcomes for people with this condition.

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IgA nephropathy affects the glomeruli, the tiny filters inside the kidneys. Current understanding describes a multi-step process in which the body produces a form of IgA1 antibody that is deficient in galactose, a sugar molecule normally attached to it. The immune system then appears to generate antibodies against this altered IgA1, and the resulting immune complexes settle in the glomerular mesangium, triggering inflammation, cell proliferation, and gradual damage to the filtering structures. IgA nephropathy is considered the most common primary glomerulonephritis worldwide, though its frequency varies widely by region and is described as higher in parts of Asia and Europe and lower in populations of African descent. Research describes a wide range in long-term outcomes, and it is thought that a meaningful share of people with the condition eventually progress toward reduced kidney function, which is part of why early detection and specialist follow-up matter.

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Membranous nephropathy affects the glomerular filtering membrane, the layer inside the kidney's filters that normally keeps protein in the blood. In most cases the immune system is thought to produce antibodies, most often against a podocyte protein called PLA2R and less commonly against THSD7A, and these antibodies form immune deposits on the outer surface of the filtering membrane. Over time the membrane thickens and the filter's structure changes in a way that lets protein leak into the urine. Membranous nephropathy is described as one of the most common causes of nephrotic syndrome in adults, and it can appear at any age. In roughly a third of cases the condition improves on its own with conservative management, and in another third it is understood to carry a higher risk of progressing toward reduced kidney function over the following decade, which is why ongoing monitoring matters.

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Lupus nephritis is kidney inflammation that develops alongside systemic lupus erythematosus (SLE), a systemic autoimmune condition. Current understanding describes immune complexes and autoantibodies binding to structures within the glomerulus and surrounding kidney tissue, which draws in inflammatory cells and can damage the filtering units over time. It is one of the more serious manifestations of lupus and is described in the research literature as a significant contributor to illness and reduced kidney function among people with the disease. Research describes kidney involvement occurring in roughly half of people with SLE, and it can sometimes be the first sign that leads to a lupus diagnosis. Because the course varies widely from person to person, ongoing monitoring and specialist care play a central role in protecting long-term kidney function.

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Anti-GBM disease affects the glomeruli, and sometimes the lungs, when the immune system produces antibodies against a specific protein within type IV collagen, a structural component of the glomerular basement membrane and, in the lungs, the alveolar membrane. These antibodies bind directly to that membrane and trigger a rapid, small-vessel inflammatory process that can impair kidney filtering and, when the lungs are involved, gas exchange. Anti-GBM disease is considered rare, and research describes it as accounting for around one in five cases of a pattern of rapidly progressive kidney inflammation called crescentic glomerulonephritis, while remaining an uncommon cause of kidney failure overall. Because the disease can move quickly, prompt specialist treatment, often combining plasma exchange with immune-suppressing medication, is considered central to preserving kidney function and, when present, lung function.

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Autoimmune interstitial nephritis affects the interstitium, the tissue between the kidney's filtering tubules, where inflammatory immune cells gather and can reduce kidney function over time. Current understanding describes an immune reaction directed against the kidney's tubular tissue, and in some people this occurs together with inflammation in the eye, a pairing known as TINU syndrome (tubulointerstitial nephritis and uveitis). It can also appear alongside other autoimmune conditions such as lupus or Sjogren's. TINU syndrome itself is considered rare and research describes it as accounting for a small share of all uveitis cases, roughly two percent, and solid population-wide prevalence figures for autoimmune interstitial nephritis as a whole are limited, since much of what is known comes from case series rather than large population studies. Corticosteroids are the usual first treatment, with other immune-modulating medications reserved for cases that do not respond.

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ANCA-associated glomerulonephritis affects the glomeruli as part of a small-vessel vasculitis. Current understanding describes antibodies called ANCA, most often directed against the proteins myeloperoxidase (MPO) or proteinase 3 (PR3), activating certain white blood cells in a way that damages the walls of small blood vessels in the kidney and can involve other organs as well. The resulting kidney injury is often described as pauci-immune, meaning there is comparatively little antibody deposit visible in the kidney tissue itself despite the antibody-driven process behind it. ANCA-associated vasculitis as a group is considered rare, and researchers note that its true incidence and prevalence have been difficult to pin down precisely, though a growing body of epidemiological work over the past two decades has revealed patterns by age, geography, and ethnicity. Kidney involvement is common when the disease is active, and because it can progress quickly, prompt specialist care matters for preserving kidney function.

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Minimal change disease is considered autoimmune-related or immune-mediated. It affects the podocytes of the glomerular filter, and current understanding proposes a T-cell-driven process in which podocytes begin expressing a protein called CD80 (also known as B7-1) on their surface, which alters the shape of these cells and the integrity of the filter's slit-like openings, letting protein leak into the urine. Normally this CD80 expression is brief and self-regulating, and researchers describe minimal change disease as involving a failure of that regulatory step, so the protein leak persists, even though the kidney tissue looks nearly normal under a standard microscope. Minimal change disease is described as the cause of idiopathic nephrotic syndrome in a large majority of young children, and it also occurs in adults, where it accounts for a smaller share of cases and can behave somewhat differently, sometimes needing a longer course of treatment.

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Autoimmune uveitis affects the uvea, the middle layer of the eye that includes the iris and the tissue feeding the retina. Current understanding describes immune cells, including T-cells, breaking through the eye's normally protective blood-ocular barrier and mounting a local inflammatory response against eye tissue, sometimes in a recurring or remitting pattern. It can occur on its own or alongside a systemic autoimmune or inflammatory disease, and certain patterns link to specific conditions: uveitis at the front of the eye is associated with the HLA-B27 gene and conditions such as ankylosing spondylitis, and uveitis at the back of the eye is more associated with Behcet's disease. Research describes spondyloarthritis, Behcet's disease, and sarcoidosis as having the largest impact on how common uveitis is overall, though a precise population-wide prevalence figure specific to the autoimmune forms is not well established. Because it can threaten vision, prompt care from an eye specialist is important.

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Optic neuritis affects the optic nerve, the cable that carries visual signals from the eye to the brain. Current understanding describes an immune-mediated attack on the nerve's myelin coating, which disrupts the transmission of visual signals and can, over time, contribute to nerve fiber damage as well. It is closely linked to multiple sclerosis, and research also describes specific antibody-defined forms, including cases tied to aquaporin-4 antibodies (associated with neuromyelitis optica spectrum disorder) and cases tied to MOG antibodies, alongside a larger group in which neither antibody is found. Optic neuritis is described as the most common optic nerve disorder affecting young adults, with an estimated incidence of around 5 cases per 100,000 people per year in central Europe, and it is markedly more common in women. Close to half of people with multiple sclerosis develop optic neuritis at some point, and for some it is the first sign of the disease. Many people recover a meaningful amount of vision over weeks to months.

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Scleritis affects the sclera, the tough white outer wall of the eye, which becomes inflamed, swollen, and painful. In many cases the immune system is thought to drive this inflammation as part of an underlying autoimmune disease such as rheumatoid arthritis, granulomatosis with polyangiitis, lupus, or Sjogren's syndrome, and a smaller share of cases are linked to infection rather than autoimmunity. A 2025 systematic review and meta-analysis described scleritis as a rare condition overall, and found that roughly a quarter to over 40 percent of people with scleritis have an associated immune-mediated disease, most commonly rheumatoid arthritis, vasculitis, or inflammatory bowel disease, with rates varying by region, age, and study population. Because scleritis can threaten vision, it needs prompt care from an eye specialist.

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Thyroid eye disease affects the tissues and muscles in the eye socket behind and around the eyes. Antibodies against the thyroid-stimulating hormone receptor, along with antibodies against the insulin-like growth factor-1 receptor, are thought to trigger an inflammatory cascade that activates orbital fibroblasts and leads to swelling and expansion of the orbital tissue. It most often accompanies Graves' disease and its related hyperthyroidism, though a small share of people with thyroid eye disease have normal or even low thyroid function. A 2025 review described the age-adjusted annual incidence of clinically significant disease as an estimated 16 per 100,000 women and 2.9 per 100,000 men, and noted that most cases are mild, with about 1 in 5 moderate to severe. Risk factors include smoking and the level of thyrotropin receptor antibodies, and cases that threaten vision need prompt specialist care.

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Cogan's syndrome affects the eyes and the inner ears, and is understood as a rare form of autoimmune vasculitis, inflammation of small and medium blood vessels. The immune system appears to inflame eye tissue such as the cornea, causing interstitial keratitis, alongside the structures of hearing and balance in the inner ear, with cytokines and immune cell activity thought to drive tissue damage in both sites. A 2025 comprehensive review described it as affecting mainly young adults and noted that roughly 7 in 10 people with the condition also have some form of systemic vasculitis. Because the literature is limited to case series and small cohorts, precise prevalence figures are not well established, and there are no specific diagnostic biomarkers, so it is typically diagnosed by ruling out other conditions. Because it can threaten both vision and hearing, it needs prompt specialist care.

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Sympathetic ophthalmia affects both eyes after one eye has been injured or had surgery. The immune system appears to react to pigment-containing tissue released from the injured eye, exposing eye-specific proteins that the immune system does not normally encounter, and a delayed hypersensitivity response then inflames the uvea of the uninjured eye as well. It is considered a rare condition. Research describes the estimated incidence as roughly 0.2 to 0.5 percent following penetrating eye injuries and about 0.01 percent following intraocular surgery, and onset can range from days to decades after the original injury, though most cases develop within the first year. Because it can threaten sight in the uninjured eye, it needs prompt care from an eye specialist, and management typically involves corticosteroids alongside longer-term immunomodulatory therapy.

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Susac syndrome affects the small blood vessels of the retina, the inner ear, and the brain. It is understood as an immune-mediated endotheliopathy, where the immune system appears to injure the lining of those tiny vessels, involving cytotoxic T-cells and antibodies against endothelial cells that are thought to reduce blood flow to affected tissue. It is a rare disorder that predominantly affects young women. A 2025 systematic review pooling 435 published cases found a median age at diagnosis of 35 years, with neurological symptoms present in about 87 percent of cases, hearing loss common among those with ear involvement, and retinal artery blockages common among those with eye findings, though the full triad of all three was present at onset in only around 1 in 5 people, which can delay diagnosis. It needs prompt specialist care.

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Autoimmune inner ear disease affects the inner ear, the organ of hearing and balance. The immune system is thought to mistakenly target inner-ear tissue through mechanisms that may include molecular mimicry, where immune cells trained to recognize an infection cross-react with similar-looking proteins in the ear, and a bystander effect in which nearby healthy tissue is damaged during an unrelated immune response. Antibodies against heat shock protein 70 have been studied as a possible marker of cochlear damage, though no biomarker is reliable enough yet for routine diagnosis, so it remains a diagnosis of exclusion. It is included here as an ear condition and is considered rare, with research describing an estimated incidence of fewer than 5 cases per 100,000 people. It can occur alongside a systemic autoimmune disease, and prompt specialist care matters because hearing can be at stake.

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Birdshot chorioretinopathy affects the choroid and retina at the back of the eye. It is understood as an immune-driven inflammation of these tissues, and carries one of the strongest known associations between a genetic marker, the HLA-A29 allele, and any human disease, with more recent research pointing to a gene called ERAP2 as a contributor to how that genetic risk translates into disease. A 2022 review described it as affecting mainly middle-aged adults of European descent, with a mean age at presentation of 53 and a slight female predominance, and noted that at least 96 percent of reported cases test positive for HLA-A29. It is chronic and can progress, and there is no single agreed treatment protocol, so ongoing care with an eye specialist matters for protecting vision, typically involving corticosteroids and often longer-term immunosuppressive therapy.

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Ocular cicatricial pemphigoid affects the conjunctiva, the thin membrane lining the eye and inner lids, and is considered a subtype of the broader condition mucous membrane pemphigoid. Antibodies and immune complexes are thought to target the basement membrane beneath the conjunctival surface, drawing in inflammatory cells and triggering fibrogenic growth factors that drive progressive scarring. It is a rare disease that mainly affects older adults, with a 2019 cohort study and literature review reporting an average age at diagnosis in the mid-70s and involvement of the mouth or skin in a meaningful share of cases alongside the eyes. Because the scarring can progress and threaten the cornea and vision, it needs prompt and ongoing specialist care, typically with immunosuppressive treatment aimed at slowing the inflammatory process.

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Mooren's ulcer affects the cornea, the clear front window of the eye, and is described as a painful autoimmune form of peripheral ulcerative keratitis. The immune system is thought to target a specific molecule in the corneal stroma in people who are genetically susceptible, with the reaction sometimes provoked by a prior trigger such as ocular trauma, surgery, or certain infections, though a specific cause is not identified in every case. A 2025 review described it as rare and noted that it occurs more often in parts of the Indian subcontinent, China, and central Africa than in the northern hemisphere, with incidence and severity varying by region, and it still lacks large-scale prevalence data and standardized diagnostic criteria. It can progress to corneal thinning and perforation and carries a risk of vision loss, so it needs prompt care from an eye specialist.

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Sarcoidosis affects the lungs and lymph nodes most often, and can involve the skin, eyes, heart, liver, or nervous system. The immune system is thought to overreact to an environmental or infectious trigger in a person with a genetic susceptibility, forming tiny clusters of inflammatory cells called granulomas in the affected tissue. It is generally described as immune-mediated rather than classically autoimmune, since it does not center on antibodies attacking the body's own tissue the way lupus does. Research describes sarcoidosis as having wide variation in incidence by region, race, and sex, and much about its underlying cause remains unclear despite over a century of study. At least 90 percent of people with sarcoidosis show some lung involvement, and the disease can range from a finding on incidental imaging to a serious multi-organ illness.

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IgG4-related disease is an immune-mediated condition in which inflammation and fibrous, tumor-like swelling build up in one or more organs, often paired with high blood levels of a specific antibody subtype called IgG4. Current understanding describes a T-helper type 2 dominant immune response that drives this process, with T cells, B cells, plasma cells, and innate immune signaling all contributing to the tissue swelling and scarring. It most often affects the pancreas, tear and salivary glands, the tissue behind the abdomen, kidneys, and lungs, and can mimic cancer or infection on imaging, which makes diagnosis a careful process of ruling out other causes. IgG4-related disease was only recognized as a distinct entity in the past two decades, so epidemiologic knowledge is still described as limited, though research notes it appears more common in men. Most people respond well to glucocorticoid treatment initially, and relapse during tapering is common, so ongoing monitoring matters.

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Autoimmune myocarditis is inflammation of the heart muscle driven by the immune system rather than by an active infection, though it can sometimes follow a viral illness. Current understanding describes several contributing factors, including existing autoimmune disease elsewhere in the body, viral triggers, genetic and hormonal influences, and immune cells mistaking heart tissue for a foreign threat, sometimes through a CD4 T-cell driven inflammatory process. Myocarditis overall is estimated to affect roughly 4 to 14 people per 100,000 each year worldwide, and most adults present with chest pain, and some with shortness of breath or fainting. Only a subset of these cases are specifically autoimmune, such as giant cell myocarditis or eosinophilic necrotizing myocarditis, and it can occur alone or alongside conditions such as lupus. Symptoms can range from mild to serious, and the acute form can be life-threatening and needs prompt specialist care.

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Autoimmune interstitial lung disease is inflammation and sometimes scarring of the lung tissue linked to an immune-mediated process, often occurring alongside conditions such as rheumatoid arthritis, scleroderma, or myositis. In these connective tissue diseases the immune system's activity against the body's own tissue extends to the delicate lung tissue surrounding the air sacs, making the lungs stiffer over time and gas exchange harder. Research describes a related pattern called interstitial pneumonia with autoimmune features, used when a person has lung scarring and some laboratory or clinical signs of autoimmunity and up to 90 percent of these patients show positive antinuclear antibodies, without meeting full criteria for a specific connective tissue disease. Interstitial lung disease is common in systemic sclerosis, polymyositis and dermatomyositis, and rheumatoid arthritis, and is described as a leading cause of illness and mortality among people with these conditions. The most common symptoms are a persistent dry cough and gradually worsening shortness of breath, often developing slowly over months.

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VEXAS syndrome is a rare, adult-onset condition caused by an acquired mutation in the UBA1 gene within blood-forming cells, which leads to widespread inflammation and blood abnormalities. It is classed as an autoinflammatory disease, meaning the innate immune system drives the inflammation, rather than a classic antibody-based autoimmune disease, though it can overlap with autoimmune and blood conditions such as myelodysplastic syndrome. Because the mutation arises in the X chromosome and is acquired rather than inherited, VEXAS is described almost exclusively in men, typically diagnosed after age 50. Research estimates it affects roughly 1 in 4,000 men over 50, making it more common than once assumed for a condition first described only in 2020, and some regional cohorts report lower prevalence than others. People often have recurring fevers, skin and cartilage inflammation, lung and blood vessel involvement, and low red blood cell counts with enlarged red cells, and the condition carries meaningful risk from both the inflammation itself and related infections.

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Schnitzler syndrome is a rare, adult-onset condition that pairs a chronic hive-like rash with a specific abnormal blood protein, most often a monoclonal IgM gammopathy, and signs of ongoing inflammation. Current understanding describes it as a late-onset acquired autoinflammatory syndrome in which the inflammatory signal interleukin-1 plays a central role, rather than a classic antibody-against-self autoimmune disease. Research notes that the relationship between the autoinflammatory features and the abnormal blood protein is still not fully understood, and the underlying mechanism remains an area of active study. Because it is extremely rare, precise prevalence figures are not well established in the literature, and diagnosis often takes years since the combination of symptoms is uncommon and easy to mistake for other conditions. A notable feature is that people with Schnitzler syndrome tend to respond well to medications that block interleukin-1, which supports the autoinflammatory understanding of the disease.

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Autoinflammatory syndromes are a family of conditions in which the innate immune system, the body's fast, non-specific first line of defense, switches on inappropriately and causes recurring inflammation. This is distinct from classic autoimmunity, where the immune system makes antibodies or specialized cells that target the body's own tissue. Familial Mediterranean fever, the most studied example, is caused by changes in the MEFV gene, inherited in an autosomal recessive pattern, that alter a protein called pyrin involved in regulating the innate immune system, leading to uncontrolled production of the inflammatory signal interleukin-1. It is described as the most prevalent monogenic autoinflammatory periodic fever syndrome worldwide, occurring predominantly in people with ancestry from the Mediterranean basin, including Turkish, Armenian, Arab, and Sephardic Jewish populations. In FMF, episodes typically bring sudden fevers along with belly pain, chest pain, or painful, swollen joints, often lasting one to three days before easing, and many people feel well between episodes, though long-term complications such as kidney involvement can develop without treatment.

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Chronic recurrent multifocal osteomyelitis is a rare, non-infectious bone condition that mainly affects children and adolescents and is considered autoinflammatory, meaning the innate immune system drives inflammation in the bone without any infection present. Despite the word osteomyelitis, which usually means a bone infection, cultures in CRMO are sterile and antibiotics do not resolve it. Research describes three main proposed mechanisms behind the disease: imbalanced cytokine signaling from innate immune cells, increased activation of the inflammasome, and enhanced activity of the bone-resorbing cells called osteoclasts, occurring without the autoantibodies or antigen-specific T cells seen in classic autoimmune disease. It tends to follow a waxing and waning course that is often worse at night, and because it is rare, exact prevalence figures are not well established, though it is increasingly recognized as clinicians become more familiar with its imaging pattern. The main symptom is bone pain, often with swelling and tenderness, most commonly in the long bones, collarbone, spine, pelvis, or jaw, and some children also have related skin or gut inflammation.

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Autoimmune progesterone dermatitis is a rare, autoimmune-related skin condition in which the body reacts to its own progesterone, the hormone that rises in the second half of the menstrual cycle. Because the reaction is tied to a natural hormone and follows the cycle, the rash tends to appear in a predictable pattern in the days before a period, when progesterone peaks, and ease again once menstruation begins. It is described as a cyclical hypersensitivity reaction, and presentations vary widely, ranging from hives and eczema-like patches to target-shaped lesions and, rarely, anaphylaxis. A systematic review of the published literature found only around 50 documented cases of the condition worldwide, underscoring how rare and likely underdiagnosed it is, since many milder cases may never be evaluated or correctly identified. Diagnosis typically involves a skin test using progesterone itself, and treatment focuses on suppressing ovulation or desensitizing the immune response to progesterone, since the condition is tied directly to the hormonal cycle.

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PANS (pediatric acute-onset neuropsychiatric syndrome) and PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) describe a sudden, dramatic onset of obsessive-compulsive symptoms or severe food restriction in children, often after an infection. PANDAS is considered a subset of the broader PANS category and is specifically linked to group A streptococcal infection, while PANS can follow a wider range of infectious or environmental triggers. Current understanding proposes that in a susceptible child, the immune response to infection involves autoantibodies, complement activation, and inflammatory signaling that affect the basal ganglia, a brain region involved in movement and behavior regulation, based on imaging studies, though the exact mechanism is still debated among researchers and the diagnostic entities themselves remain somewhat controversial in the medical literature. Onset is typically between about 2 and 14 years old, and the abrupt onset of obsessive-compulsive behaviors or eating restriction is often accompanied by tics, anxiety, mood swings, sleep disruption, and sometimes a return of bedwetting. Because research is still evolving, precise prevalence figures are not firmly established, and the relapsing-remitting course means some children improve while others have a more persistent path.

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Multifocal fibrosclerosis is an older term for a condition in which fibrous, scar-like inflammation develops in several places in the body at once, such as the tissue behind the abdomen (retroperitoneal fibrosis), around the eye socket, the thyroid, and the tissue in the chest. Research describes many cases once labeled multifocal fibrosclerosis as now falling within the broader spectrum of IgG4-related disease, an immune-mediated condition marked by tissue infiltration with IgG4-positive plasma cells and progressive fibrosis, though not every case of fibrosclerosis has this IgG4 pattern. Idiopathic retroperitoneal fibrosis, the most studied example, accounts for the large majority of retroperitoneal fibrosis cases and is generally responsive to immune-suppressing treatment such as corticosteroids, which supports an immune-mediated understanding of the disease. Because the condition is rare and the terminology has shifted substantially as understanding of IgG4-related disease has developed, precise prevalence figures for multifocal fibrosclerosis specifically are not well established in the literature. Symptoms depend on where the fibrous inflammation sits, ranging from back or flank pain and kidney effects to eye changes, neck swelling, or chest symptoms.

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Erythema nodosum is not a disease in itself and is instead a reaction pattern, an inflammatory response in the fatty layer under the skin that shows up as tender red bumps, usually on the shins. It reflects inflammation of the small veins and connective septa within the fat layer, described in the literature as a form of panniculitis, and is the skin's way of reacting to something else going on in the body. Research describes streptococcal throat infection, sarcoidosis, inflammatory bowel disease, and certain medications as among the most frequent identifiable triggers, though in roughly half of cases no clear underlying cause is found. It affects women more often than men, with studies estimating women make up around 83 percent of cases, and the peak incidence falls between ages 18 and 34, though it can occur at any age. Many people also have a general feeling of being unwell, low fever, and joint aches, and the bumps typically heal on their own over a few weeks without scarring.

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Autoimmune lymphoproliferative syndrome is a rare inherited condition in which the body cannot properly clear out old immune cells through normal programmed cell death, a process called apoptosis, most often because of changes in the FAS gene. As a result, lymphocytes build up in the lymph nodes and spleen, and the immune system becomes prone to attacking the body's own blood cells. Research attributes roughly 60 to 70 percent of ALPS cases to FAS gene mutations, with a smaller share linked to changes in the FAS ligand or caspase 10 genes, and it usually appears in childhood with persistent swollen lymph nodes and an enlarged spleen. Because normal apoptosis fails, the excess immune cells produce characteristic laboratory findings, including elevated interleukin-10, elevated IgG, and a distinctive population of double-negative T cells that clinicians use to help confirm the diagnosis. Along with autoimmune destruction of blood cells that can cause anemia, low platelets, and easy bruising or fatigue, people with ALPS carry a higher lifetime risk of certain lymphomas, so ongoing monitoring matters.

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Common variable immunodeficiency is a primary immune deficiency in which the body makes too few protective antibodies, arising from impaired antibody production linked to defects in B-cell development and, often, accompanying abnormalities in T-cell regulation, leaving a person more prone to infections. In a notable share of people with CVID, this same underlying immune dysregulation also allows the immune system to turn against the body's own tissue, producing autoimmune features, which is why it is marked here as autoimmune-related. Research describes autoimmunity as occurring in up to 30 percent of people with CVID, making it an increasingly recognized cause of illness beyond the recurrent infections that typically bring the condition to attention. The most common autoimmune manifestations are cytopenias, meaning immune-driven destruction of blood cells, including immune thrombocytopenia, hemolytic anemia, and neutropenia, alongside organ-specific inflammation that can involve the gut, skin, joints, or lungs. Frequent or stubborn infections, especially of the sinuses and lungs, remain the most typical presenting feature, often with digestive problems and at times enlarged lymph nodes or spleen.

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