Ulcerative colitis is an inflammatory disease of the bowel, that usually affects the distal end of the large intestine and rectum. It has no known cause, although there is a genetic component to susceptibility.

Ulcerative colitis is similar to Crohn's disease, but there are characteristic differences: ulcerative colitis is usually confined to the mucosa and submucosa, and affects whole areas of intestine. (Crohn's disease tends to be patchy, and affect more layers of intestine.)

Table of contents
1 Features
2 Cause
3 Diagnosis
4 Course
5 Treatment


  • Chronic (> 6 months) of bloody diarrhea.
  • No infective cause of diarrhea found.
  • Inflammatory changes are mainly left sided or in the distal large bowel.
  • Disease variable in severity from patient to patient and time to time.
  • Significant risk of carcinoma after 10 years, which may in some cases require frequent surveillance biopsies or even prophylactic bowel removal.
  • Patients may have other auto-immune features.


The cause of ulcerative colitis is unknown, although infective agents have been suspected, and there is a genetic component to susceptibility.


A long-standing history of bloody diarrhea, with no sign of infection, is consistent with ulcerative colitis. A biopsy can help confirm the diagnosis. Ulcerative colitis mainly affects the left side of the colon.


People with ulcerative colitis will initially have bloody diarrhea (the severity of which is variable from time to time).

Because of destruction of the nerves in the bowel, movement may be impaired, and the intestine may dilate. This results in an extreme diarrheal disease, toxic megacolon.

Eventually the inflamed mucosa develops a risk of malignancy, requiring biopsy every few months. Sometimes the risk of malignancy is such that bowel resection is offered.


Anti-diarrheal drugs should be avoided unless under specific doctors orders, as they can worsen the disease.

Anti-inflammatory drugs (such as Sulfasalazine) can be used, and in severe cases steroids may be given.

See also: Gastroenterology, Crohn's disease