Ulcerative colitis is an inflammatory bowel disease (IBD) in which the lining of the large intestine (colon or bowel) and rectum become inflamed. Inflammation usually starts in the rectum and lower intestine and spreads up to the entire colon. Ulcerative colitis rarely affects the small intestine, except for the lower section, the ileum. The inflammation caused by ulcerative colitis can lead to diarrhea, or frequent emptying of the colon. As cells on the surface of the lining of the colon die and fall off, ulcers (open sores) form and may cause the release of pus and mucus, in addition to bleeding. The symptoms of ulcerative colitis may resemble other medical conditions or problems so make sure to consult your doctor for a diagnosis if any appear. Ulcerative colitis requires long-term medical care. There may be remissions—periods when the symptoms go away—that last for months or even years. However, usually symptoms return eventually. Cause The cause of ulcerative colitis is unknown. One theory suggests that a virus or an unusual bacterium interacts with the body's immune system to trigger an inflammatory reaction in the intestinal wall. Although a lot of scientific evidence shows that people with ulcerative colitis have abnormalities of the immune system, doctors don't know whether these abnormalities are a cause or result of the disease. There is little proof that ulcerative colitis is caused by emotional distress or sensitivity to certain foods or food products, or is the result of an unhappy childhood as some theories suggest. Risk Factors Children and older people sometimes develop ulcerative colitis, but it most often starts between the ages of 15 and 30. It affects males and females equally and appears to run in some families. Diagnosis Diagnosis includes a thorough physical examination, including blood tests to determine whether an anemic condition exists, or if the white blood cell count is elevated (a sign of inflammation). In addition, diagnostic procedures for ulcerative colitis may include a stool culture, upper endoscopy, colonoscopy, biopsy, or barium enema. Prevention While there is no special diet for ulcerative colitis, people may be able to control mild symptoms simply by avoiding foods that seem to upset their intestines. Treatment Currently there is no way to cure ulcerative colitis, except by removing the colon. Treatment may include drug therapy, periods of hospitalization, or surgery, and a person under treatment may require emotional and psychological support. Current available medical therapies, including corticosteroids and approved biologic drugs, have induced remissions in a large percentage of patients who have ulcerative colitis. The disease is fatal only in rare cases where complications develop. If just the rectum and lower colon are involved, the risk of cancer is not higher than normal. But the risk of colon cancer is greater than normal in patients with widespread ulcerative colitis.