What is Ulcerative Colitis? l United Ostomy Associations of America

What is Ulcerative Colitis?

Ulcerative colitis is chronic inflammation that generally affects the large intestine (colon) and rectum. Compared to Crohn’s disease, in ulcerative colitis (UC), the inflammation may be located more often on the surface of the colon or rectum and does not penetrate the bowel walls.

Ulcerative colitis may present in the following ways:

It can present only in the rectum as proctitis.

It can also present as distal colitis, which starts at the rectum and extends up to the left colon, meaning the sigmoid colon and descending colon, (sigmoid colon and descending colon).

It can also present as pancolitis, which involves inflammation of the entire colon and rectum.

Please see Figure 3 for a better understanding of how ulcerative colitis can present in the colon.

Figure 3. Ulcerative Colitis

Complications of Ulcerative Colitis

Toxic Megacolon: The colon may expand, dilate or distend, which prevents waste from being eliminated from the body. This may eventually result in the colon rupturing and the development of sepsis; toxic megacolon is very serious and usually requires immediate surgical attention.

Crohn’s Disease vs. Ulcerative Colitis

There can often be confusion around the distinction between Crohn’s disease and ulcerative colitis. This may be referred to as indeterminate colitis, especially if the inflammation and ulcerations are present in the colon and rectum, though without the typical penetrating features and skip lesions that patients with Crohn’s disease may have. When Crohn’s disease is present in the colon, this is referred to as Crohn’s colitis, NOT as someone having both ulcerative colitis and Crohn’s disease.

As such, in recent years, Crohn’s disease and ulcerative colitis (and the specific locations the disease presents in) are being referred to as a spectrum, or continuum, of inflammatory bowel diseases, rather than two separate diseases. Doctors are focusing more on the location of the disease and how it is presenting rather than categorizing the disease as specifically Crohn’s disease or ulcerative colitis

Written by Tina Aswani Omprakash. Medically reviewed and validated by Jordan Axelrad, MD, MPH. These webpages are funded by a grant from The Leona M. and Harry B. Helmsley Charitable Trust.