The course of inflammatory bowel disease.

Ulcerative colitis (UC) and Crohn's disease (CD) are chronic disorders affecting mostly young people, punctuated by relapses and remissions. There is a pattern for UC based on the original extent of colon involved. Ulcerative proctosigmoiditis is a limited form of the disease with a generally benign course. Although UC tends to relapse, treatment reduces the relapse rate. CD has protean manifestations. The anatomic location and extent of disease tends to determine the clinical course. Most patients require surgery, and recurrences are common.