Encyclopedia / I / Inflammatory Bowel Disease

Inflammatory Bowel Disease


Article updated and reviewed by Christian D. Stone, M.D., Assistant Professor of Medicine, Division of Gastroenterology, Washington University in St. Louis School of Medicine on May 19, 2005.

Inflammatory bowel disease is a name given to a group of chronic digestive diseases of the small and large intestines. Your doctor may refer to your particular condition by any one of several terms, including colitis, proctitis, enteritis and ileitis.


Most often, doctors divide IBD into two groups: Ulcerative colitis and Crohn's disease.

Ulcerative colitis causes ulcers and inflammation of the lining (mucosa) of the colon (large intestine). It almost always involves the rectum and usually causes bloody diarrhea.

Crohn's disease Crohn's disease is an inflammation that extends into the deeper layers of the intestinal wall. The disease is either limited to one or more segments of the small intestine (usually the ileum) or involves both the ileum and the colon (ileocolitis). In some, Crohn's disease is confined to the colon (Crohn's colitis). Sometimes, inflammation may also affect the mouth, esophagus, stomach, duodenum, appendix or anus.

Both ulcerative colitis and Crohn's disease are chronic conditions and may recur over a lifetime. On the other hand, many people will have long periods, sometimes years, when they will be free of symptoms. Unfortunately, doctors cannot predict with certainty when the disease will go into remission or when the symptoms will return.

It is estimated that between 1 and 2 million Americans suffer from IBD. Men and women are affected about equally. The number of people who develop Crohn's disease has been increasing steadily over the last several decades. The incidence has, in the past, been highest in North America, the British Isles, northwest Europe and Scandinavia. In recent years, an increase in frequency has been observed in developing nations throughout the rest of the world. Doctors cannot yet explain why these changes are occurring.


There are many theories about what causes IBD, but none have been proven. A leading theory suggests that bacteria normally residing in the intestinal lumen interact with the body's own immune defense system to trigger an inflammatory reaction in the intestinal wall. Environment also plays a role, as cigarette smoking is a known risk factor for Crohn’s disease but is protective in ulcerative colitis. Lastly, genetics are important. Persons with certain genetic mutations are more susceptible to acquiring IBD but these alone are not sufficient to cause the disease. IBD is more common among Jews and Caucasians than African-Americans, Asians, Hispanics or Native Americans, although no population group is immune from attack.

Although there is much scientific evidence that patients with IBD have abnormalities of the immune system, doctors do not know whether these abnormalities are a cause or a result of the disease. Doctors believe that there is little basis for the idea that Crohn's disease and ulcerative colitis are caused by stress or diet.

The diagnosis of IBD can usually be established by a good medical history, x-ray examination of the digestive tract, and endoscopy.


The most common symptoms of IBD are diarrhea and abdominal pain. Ulcerative colitis usually causes rectal bleeding, as well. Crohn's disease also may cause rectal bleeding, but less often than does ulcerative colitis.

In either disease, fever, fatigue, joint pain, weight loss and/or anemia (a low red blood cell count) may occur. Children may also suffer stunted growth and delayed development.


No medicine has yet been found to cure Crohn's disease or ulcerative colitis, but there are many drugs helpful in controlling the disease processes and symptoms. The principle drugs currently used to treat both Crohn's disease and ulcerative colitis are mesalamine (Asacol, Pentasa, Rowasa) given orally or rectally, sulfasalazine (Azulfidine), and corticosteroids (prednisone, hydrocortisone, etc.). Nearly all medicines used to treat inflammatory bowel disease reduce inflammation by suppressing the body’s immune response either locally within the intestines or systemically throughout the body. Other drugs commonly used in these diseases are azathioprine (Imuran, Azasan), mercaptopurine (Purinethol), and the newer agent infliximab (Remicade). In addition, there are numerous other medications that may work in Crohn’s disease, but not for ulcerative colitis or vice versa.

Abdominal cramps and diarrhea may be alleviated by drugs like loperamide and codeine. Sometimes, antibiotics like metronidazole are used, especially for Crohn’s disease involving either the colon alone or the perianal area.

Some cases of IBD improve with other drugs that suppress the body's immune system. Examples include azathioprine, methotrexate and infliximab. These treatments sometimes produce severe reactions, so close monitoring by your doctor is necessary.

No special diet has been proven effective for preventing or helping IBD. Maintaining good general nutrition and adequate caloric intake is far more important than emphasizing or avoiding any particular food. Stopping smoking is critical to the treatment of Crohn’s disease.

Surgery can cure ulcerative colitis. Although most patients cope effectively with this disease for many years, about one-third will eventually require the removal of the colon. In the standard form of this operation the entire colon and rectum are removed. A small opening (stoma) is made in the front of the abdominal wall and the tip of the lower small intestine (ileum) is then brought through. The stoma is fitted with a pouch to collect waste products. This external opening to the intestine is called an ileostomy. In many cases, the ileostomy is only temporary and the intestinal stream can be surgically reestablished by creation of an ileal reservoir (e.g. J pouch) and connecting it to the anal canal. This allows for relatively normal passage of stool per the anal canal.

Crohn's disease can be helped but not cured by surgery. The inflammation tends to return in areas of the intestine immediately next to the area that had been removed. About two-thirds of all Crohn's disease patients will require surgery at some point, either to provide relief from chronic disability or to correct specific complications.


Do I have ulcerative colitis or Crohn's disease?

What specific area of the bowel is inflamed?

What type of treatment will you be recommending?

What medications are right for me?

What are the side effects of the medications?

Will I need surgery for IBD?

Can I become pregnant if I have IBD?

Are my children at risk for getting IBD?

Editorial review provided by VeriMed Healthcare Network.