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Overview of Inflammatory Bowel Disease

By Aaron E. Walfish, MD, David B. Sachar, MD

In inflammatory bowel diseases, the intestine (bowel) becomes inflamed, often causing recurring abdominal cramps and diarrhea.

The two primary types of inflammatory bowel disease (IBD) are Crohn disease and ulcerative colitis. These two diseases have many similarities and sometimes are difficult to distinguish from each other. However, there are several differences. For example, Crohn disease can affect almost any part of the digestive tract, whereas ulcerative colitis almost always affects only the large intestine. The cause of these diseases is not known but may involve an abnormal immune reaction to intestinal bacteria or other agents in people with a genetic predisposition.

IBD affects people of all ages but usually begins before age 30, typically from age 14 to 24. IBD is most common among people of Northern European and Anglo-Saxon descent and is 2 to 4 times more common among Ashkenazi Jews. Both sexes are equally affected. First-degree relatives (mother, father, sister, or brother) of people with IBD have a 4- to 20­fold increased risk of developing IBD.


The symptoms caused by IBD vary depending on which part of the intestine is affected and whether the person has Crohn disease or ulcerative colitis. People with Crohn disease usually have chronic diarrhea and abdominal pain. People with ulcerative colitis usually have intermittent episodes of abdominal cramps and bloody diarrhea. People with longstanding diarrhea may lose weight and develop symptoms of vitamin deficiency.

Sometimes IBD causes inflammation in other parts of the body such as the joints, eyes, mouth, and skin. IBD also increases the risk of cancer in areas of the intestine that are affected.

Diagnosis and Treatment

To make a diagnosis of inflammatory bowel disease, a doctor must first exclude other possible causes of inflammation. For example, infection with parasites or bacteria may cause inflammation. Therefore, the doctor performs several tests. Stool samples are analyzed for evidence of a bacterial or parasitic infection (acquired during travel, for example), including a type of bacterial infection ( Clostridium difficile infection) that can result from antibiotic use (see Clostridium difficile -Induced Colitis). A doctor also checks for sexually transmitted diseases of the rectum, such as gonorrhea, herpesvirus infection, and chlamydial infection. Tissue samples (biopsies) may be taken from the lining of the rectum during a sigmoidoscopy (an examination of the sigmoid colon using a viewing tube) and examined microscopically for evidence of other causes of colon inflammation (colitis). Other possible causes of similar abdominal symptoms that a doctor tries to exclude are ischemic colitis, which occurs more often in people older than 50; malabsorption; certain gynecologic disorders in women; celiac disease; and irritable bowel syndrome.

Although there is no cure for IBD, many drugs (see Drugs That Reduce Bowel Inflammation Caused by Crohn Disease and see Drugs That Reduce Bowel Inflammation Caused by Ulcerative Colitis) and various other treatments can help reduce inflammation and alleviate the symptoms. People with very severe disease sometimes need surgery. Doctors sometimes recommend stress management techniques to help people deal with the stress of having a chronic disease.

Diet and stress management

Most people and their families are interested in diet and stress management. Although some people claim that certain diets have helped improve their IBD, including one with rigid carbohydrate restrictions, these claims remain unproved in clinical studies. Stress management may be helpful.

* This is the Consumer Version. *