Crohn's disease (CD)

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.

Common signs

Diarrhea, crampy abdominal pain, urgency, fatigue, fever, reduced appetite, and weight loss are common. Some people pass blood, develop mouth sores, or have problems around the anus such as fissures or fistulas. Flares and quieter periods often alternate, and inflammation outside the gut, in joints, skin, or eyes can also occur.

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.