Extraintestinal

Extraintestinal refers to tissues or organs outside the intestine. In medicine, the term is often used to describe manifestations that occur outside the gastrointestinal tract, particularly as part of inflammatory bowel disease (IBD). Extraintestinal manifestations can affect the skin, joints, eyes, liver, and biliary system, among other sites.

In inflammatory bowel disease, extraintestinal manifestations (EIMs) affect a substantial minority of patients and may parallel, precede, or follow intestinal activity. Common EIMs include erythema nodosum and pyoderma gangrenosum in the skin; peripheral arthritis and spondyloarthropathy in the joints; episcleritis and uveitis in the eyes; and primary sclerosing cholangitis or autoimmune liver conditions.

Pathogenesis is not fully understood; immune-mediated mechanisms with shared antigens or systemic inflammation are implicated. Diagnosis is clinical and supported by investigations; it requires distinguishing EIMs from primary skin, joint, or eye disease and from medication-related effects. EIMs may occur even when intestinal disease is in remission.

Management focuses on treating the underlying IBD and specific organ-directed therapies. Treatments may include corticosteroids, immunomodulators, and biologic agents such as anti-TNF therapies, which can benefit both intestinal disease and many EIMs. Involvement of relevant specialists (dermatology, rheumatology, ophthalmology) is common.

Prognosis varies by manifestation and response to therapy. While some EIMs resolve with control of intestinal inflammation, others may require ongoing treatment. Research continues to clarify pathogenesis and optimize integrated care.