Crohn’s disease and colitis (also known as ‘ulcerative colitis’) are both types of inflammatory bowel disease. They are long-term conditions that cause patches of inflammation (painful swelling and redness) and ulceration to develop in the digestive tract.
They can develop at any age, but often develop in young people aged 15 to 30 years. Slightly more women than men are affected.
Inflammation is a normal defense mechanism used by the immune system to fight off invaders, such as bacteria or viruses. Usually, inflammation is switched off once the invaders are destroyed. In Crohn’s disease and colitis a problem with the immune system causes inflammation to continue, damaging the walls of the digestive tract.
There is no single test that can be used to diagnose Crohn’s disease or colitis, so a combination of tests is usually required. This often includes a colonoscopy, where a thin flexible tube that contains a tiny camera is used to look inside the bowel. Small samples of the bowel lining may also be taken for testing.
The main difference between the two diseases is the extent of inflammation they cause:
Colitis only affects the large bowel (colon and/or rectum), and inflammation is only in the surface layers of the bowel lining. Colitis is also sometimes called ‘ulcerative colitis’ because it causes ulcers (tiny sores) to form in the lining of the bowel.
Crohn’s disease can affect any part of the digestive tract from mouth to anus (back passage) but usually affects the last section of the small bowel (the ileum) and/or the colon. Inflammation can extend into the entire thickness of the bowel wall.
While Crohn’s disease and colitis cannot be cured, their symptoms can usually be managed using medications that control inflammation. Sometimes surgery can also help.
Sources: Crohn’s and Colitis Australia (What is ulcerative colitis?, What is Crohn’s disease?, What is IBD?), Gastroenterological Society of Australia (Publication - GESA, DHF. Information about Inflammatory Bowel Disease (IBD) Crohn’s disease and ulcerative colitis. (2011)), Digestive Health Foundation (Publication - Andrews JM, Sinclair M. Australian Guidelines for General Practitioners and Physicians. Inflammatory Bowel Disease, Third Edition, 2013.)
Last reviewed: September 2015