Inflammatory Bowel Disease: Symptoms & Signs

Medically Reviewed on 9/10/2019

The inflammatory bowel diseases (IBD) are Crohn's disease (CD) and ulcerative colitis (UC). Both of these conditions are caused by inflammation within the gastrointestinal tract, but the inflammation specific to each disease is different. Ulcerative colitis involves only the large intestine (colon), but Crohn's disease occurs throughout the gastrointestinal tract, although it most commonly affects the lower part of the small intestine (ileum). Symptoms of both conditions result from chronic inflammation that extends beyond the lining of the intestines. Complications of both include ulceration within the gastrointestinal tract and bleeding into the gastrointestinal tract. Most of the symptoms of UC can be found in patients with Crohn's disease, but Crohn's disease causes some unique symptoms and conditions not seen in people with UC, like malabsorption and small intestinal bacterial overgrowth (SIBO).

Other symptoms and signs can include weight loss, pain, vomiting, diarrhea, and fever. Bowel obstruction may occur. Some patients with IBD develop symptoms and complications outside of the intestine (extraintestinal manifestations), such as certain kinds of arthritis, rashes, eye problems, and liver disease.

Causes of inflammatory bowel disease

The cause of inflammatory bowel disease is poorly understood. These diseases are thought to be caused by a combination of genetic and environmental factors (for example, infections) that interact with the body's immune (defense) system. An abnormal activation of the immune system is believed to play a role in the development of the conditions.

Other inflammatory bowel disease symptoms and signs


Bowel regularity means a bowel movement every day. See Answer

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.