There are two types of chronic inflammatory bowel disease (IBD): ulcerative colitis and Crohn’s disease. These usually develop during the teen or young adult years, but a few people have their first attack (especially of ulcerative colitis) after age 50. These conditions appear to be associated with an overactive immune response, although the true cause is not yet known. They can be hereditary.

The severity of an IBD is determined both by the number and gravity of symptoms and the extent of bowel inflammation.

Common symptoms of IBD can include chronic diarrhea, abdominal cramps or pain, fever, and blood or mucus in the stool. The individual may lose weight and have little desire to eat. Other parts of the body can be affected when the disease flares up: there can be inflammation in joints, eyes, or skin, for example.

Other types of colitis can occur in older people and can be mistaken for one of the chronic IBDs. These include infectious colitis caused by overgrowth of bacteria or occurring as an adverse effect of chemotherapy for cancer, or colitis resulting from the use of nonsteroidal anti-inflammatory drugs such as aspirin. Also common in the elderly is ischemic colitis, caused by low blood flow to the large intestine.

A doctor will determine if an individual has an IBD with a physical examination and various tests, including a stool sample, blood tests, and sigmoidoscopy or colonoscopy, during which a tube with a small camera is inserted into the rectum to allow assessment of the bowel inflammation. X-rays may also be required.