What is the difference between ulcerative colitis and Crohn's disease?

The differences between the two include:

I) Anatomic distribution of the inflammatory process: Crohn's disease can occur in any part of the GI tract - the small intestines the colon and even the colorectal region. However, in ulcerative colitis, the inflammation is confined to left colon and rectum.

2) In Crohn's disease, inflammatory process affects the entire thickness of the wall of the small intestine leading to strictures that can cause obstructions or formation of fistulas. In ulcerative colitis the inflammatory process is in mucosa and sub mucosal tissues of the intestine and lasts for a few weeks.

Having looked at the difference between ulcerative colitis and Crohn's disease.