Inflammatory Bowel Disease

Conditions and Treatments

Inflammatory bowel disease (IBD) is a chronic inflammation of the intestines that can cause diarrhea, bleeding, abdominal pain, fever, joint pain and weight loss. IBD includes Crohn's disease, ulcerative colitis and microscopic colitis.

Crohn's Disease

Crohn's disease causes inflammation of the small intestine. Although it may involve any part of the digestive tract from the mouth to the anus, it most commonly affects the last part of the small intestine, called the ileum, and the large intestine, including the colon and rectum. This is considered a chronic condition because it may recur at various times throughout your lifetime, with periods of remission in which you are free of symptoms. There is no consistently accurate way to predict when a remission may occur or when symptoms will return.

Crohn's disease may occur in people of all ages, although most are diagnosed before the age of 30. However, it also can affect young children and older people in their seventies or beyond. Crohn's disease occurs most commonly in people living in northern climates and affects men and women equally. The condition can be inherited and is common in some families. About 20 percent to 25 percent of those with Crohn's disease have a close relative who also has the disease or the related condition, ulcerative colitis. The cause of Crohn's disease has not been proven definitely. However, the immune system's response to certain viruses and bacteria that cause inflammation of the intestines is believed to be the primary cause of the disease.

Ulcerative Colitis

Ulcerative colitis, also called colitis or proctitis, is an inflammatory bowel disease of the large intestines. Although inflammation usually occurs in the rectum and lower part of the colon, it may affect the entire colon. Unlike Crohn's disease, ulcerative colitis is limited to the colon.

It is estimated that as many as one million Americans are affected with colitis or a similar condition called Crohn's disease. Most cases of colitis are diagnosed before the age of 30, although it can affect anyone, including children and older people between the ages of 50 and 70. There is a greater incidence of the disease among Caucasians and Jews than in other populations.

The condition can be inherited and is common in some families. About 20 percent to 25 percent of those with ulcerative colitis have a close relative with the condition or Crohn's disease. The immune system's response to certain environmental antigens and the patient's own genetic makeup, are believed to be the primary factors causing disease.

Reviewed by health care specialists at UCSF Medical Center.
Last updated February 14, 2008