Ulcerative colitis is a chronic disorder that affects the digestive system. This condition is characterized by abnormal inflammation of the inner surface (epithelium) of the rectum and colon. The rectum and colon make up most of the length of the large intestine. The inflammation usually causes open sores (ulcers) to develop in the large intestine. Ulcerative colitis usually appears between the age of 15 and 30, although it can develop at any age. The inflammation tends to flare up multiple times throughout a person's life, which causes recurring signs and symptoms.\n\nThe most common symptoms of ulcerative colitis are cramping abdominal pain and frequent diarrhea, often with blood, pus, or mucus in the stool. Other signs and symptoms include nausea, loss of appetite, bowel urgency, fatigue, and fevers. Chronic bleeding from the inflamed and ulcerated intestinal tissue can cause a shortage of red blood cells (anemia) in some affected individuals. People with this disorder have difficulty absorbing enough fluids and nutrients from their diet and often experience weight loss. Affected children usually grow more slowly than normal. Less commonly, ulcerative colitis causes problems with the skin, joints, eyes, kidneys, or liver, which are most likely due to abnormal inflammation.\n\nToxic megacolon is a rare complication of ulcerative colitis that can be life-threatening. Toxic megacolon involves a widening (dilation) of the colon and an overwhelming inflammatory response. Ulcerative colitis also increases the risk of developing colon cancer, especially in people whose entire colon is inflamed and in those who have had ulcerative colitis for 8 years or more.\n\nUlcerative colitis is one common form of inflammatory bowel disease (IBD). Another type of IBD, Crohn's disease, also causes chronic inflammation of the intestines. Unlike ulcerative colitis, which affects only the inner surface of the large intestine, Crohn's disease can cause inflammation in any part of the digestive system, and the inflammation extends deeper into the intestinal tissue.

Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.

Redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin.

Photosensitivity of the skin occurring early in life.