The course of ulcerative colitis varies greatly from one person to another. Some people may have only mild symptoms, and others may have severe symptoms or complications that, in unusual cases, may be life-threatening.

Ulcerative colitis may be mild, moderate, or severe. It may be described as dependent on corticosteroids, unresponsive to steroids, or not active (in remission).

Ulcerative colitis also may be defined by the part of the large intestine affected: the rectum (proctitis), the left side of the colon (left-sided colitis), or the entire colon (pancolitis). One out of every two adults with ulcerative colitis has proctitis. Pancolitis is the most common form of ulcerative colitis in children, affecting about half.⁵

Most people with ulcerative colitis have periods of remission that may last up to several years. These periods are interrupted by occasional flare-ups of moderate symptoms. Between 5% and 10% of people have symptoms all the time.¹

Children may have the same symptoms as adults. In addition, children with ulcerative colitis may grow more slowly than normal and go through puberty later than expected.

Complications and long-term effects

• Inflammation and scarring of the bile ducts (primary sclerosing cholangitis) may occur. A bile duct is a passage that carries fluid produced in the liver to the small intestine.
• Severe inflammation and ulceration sometimes irritate muscles in the colon, causing colon walls to stretch. The colon may swell to many times its normal size, a condition known as toxic megacolon. This is an emergency that requires immediate treatment, but is rare.
• Narrowed areas of the intestine (strictures) may occur in ulcerative colitis, causing difficulty in passing stools. Abnormal connections or openings (fistulas) between parts of the intestine or between the intestine and other organs are rare because ulcerative colitis does not affect the deeper intestinal tissues.
• Your risk of cancer of the colon and rectum is higher than average if you have had ulcerative colitis for 8 years or longer. With regular screening, some cancers can be detected early and treated successfully.
• Ulcerative colitis can cause rare complications such as scarring of the pancreas and inflammation of the membrane surrounding the heart (pericarditis).

Some people who have ulcerative colitis also have irritable bowel syndrome (IBS), which is not as serious as ulcerative colitis. IBS causes abdominal pain along with diarrhea or constipation.

Most women who have ulcerative colitis are able to become pregnant and usually have healthy babies. Symptoms may become worse during the first 3 months of pregnancy. Some medicines to treat the disease can be used during pregnancy.