Inflammatory Bowel Disease Health Center

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Inflammatory Bowel Disease

Inflammatory Bowel Disease Overview

The term inflammatory bowel disease (IBD) covers a group of disorders in which the intestines become inflamed (red and swollen), probably as a result of an immune reaction of the body against its own intestinal tissue.

Two major types of IBD are described: ulcerative colitis and Crohn's disease. As the name suggests, ulcerative colitis is limited to the colon (large intestine). Although Crohn's disease can involve any part of the gastrointestinal tract from the mouth to the anus, it most commonly affects the small intestine and/or the colon.

Both ulcerative colitis and Crohn's disease usually run a waxing and waning course in the intensity and severity of illness. When there is severe inflammation, the disease is considered to be in an active stage, and the person experiences a flare-up of the condition. When the degree of inflammation is less (or absent), the person usually is without symptoms, and the disease is considered to be in remission.

Causes of Inflammatory Bowel Disease

Researchers do not yet know what causes inflammatory bowel disease. Therefore, IBD is called an idiopathic disease (disease with an unknown cause).

An unknown factor/agent (or a combination of factors) triggers the body's immune system to produce an inflammatory reaction in the intestinal tract that continues without control. As a result of the inflammatory reaction, the intestinal wall is damaged leading to bloody diarrhea and abdominal pain.

Genetic, infectious, immunologic, and psychological factors have all been implicated in influencing the development of IBD.

There is a genetic predisposition (or perhaps susceptibility) to the development of IBD. However, the triggering factor for activation of the body’s immune system has yet to be identified. Factors that can turn on the body’s immune system include an infectious agent (as yet unidentified), an immune response to an antigen (such as a protein from cow milk), or an autoimmune process. As the intestines are always exposed to things that can cause immune reactions, more recent thinking is that there is a failure of the body to turn off normal immune responses.