Ulcerative colitis (UC) involves chronic inflammation and the development of open sores (ulcers) within the large intestine.

The most common symptoms of UC are abdominal pain and bloody diarrhea. Additional signs and symptoms include mucus in the stool, tenesmus (the inability to have a bowel movement despite an urge to defecate) and unexplained weight loss. Because UC is a lifelong condition, patients often experience alternating periods of symptom activity and remission.

UC and Crohn’s disease (CD) are the two major types of inflammatory bowel disease (IBD). UC differs from CD in that it only occurs in the large intestine and only affects the innermost intestinal lining (the mucosa). CD can occur anywhere in the digestive tract and may affect all of its layers.

The large intestine consists of the cecum, ascending/transverse/descending/sigmoid colon and rectum. UC almost always involves the rectum. The other parts of the colon can be affected initially upon diagnosis of UC, or become subsequently involved.  Some patients have their entire colon affected by UC (pan-colitis) Affected areas are continuous and not separated by patches of normal tissue. UC may affect all of the large intestine or just a portion of it.

Approximately 500,000 people in the United States have UC, according to the Crohn’s & Colitis Foundation of America (CCFA). The disease  appears to have a genetic component, affecting whites and Jewish people of European descent more than other groups, and is more likely to appear in people between the ages of 15 and 35. UC occurs most often in northern climates and industrialized countries.

The cause of UC is unknown. Various diagnostic tests can help determine if a patient has the condition. These include blood tests, fecal tests and imaging tests such as a colonoscopy and barium x-ray.

Treatment goals include achieving and maintaining remission of symptoms. Anti-inflammatory drugs and medications that treat symptoms such as diarrhea, abdominal pain and loss of blood (anemia) are often recommended.

Surgery to remove the entire colon and rectum (proctocolectomy) will cure the condition, and is sometimes required when medication is ineffective, complications of the condition arise (e.g., toxic megacolon) or to treat cancerous or noncancerous changes in the large intestine. According to the National Institutes of Health (NIH), 5 percent of patients with UC develop colon cancer.