Ulcerative colitis is categorized according to location:
- Proctitis involves only the rectum
- Proctosigmoiditis affects the rectum and sigmoid colon
- Left-sided colitis encompasses the entire left side of the large intestine
- Pancolitis inflames the entire colon
Review Date: 10/26/2021
Reviewed By: Michael M. Phillips, MD, Emeritus 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.