Autoimmune hepatitis (AIH)

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.

Common signs

Many people feel tired, achy in the joints, or have vague upper-right belly discomfort, nausea, or poor appetite. As inflammation advances, yellowing of the skin or eyes (jaundice), dark urine, pale stools, itching, or a swollen abdomen can appear. Some people have no symptoms and are found through routine blood tests that show elevated liver enzymes.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.