Ulcerative colitis is categorized according to location:Proctitis involves only the rectumProctosigmoiditis affects the rectum and sigmoid colonLeft-sided colitis encompasses the entire left side of the large intestinePancolitis inflames the entire colon
Review Date: 7/10/2019
Reviewed By: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.