Colitis Home > Crohn's and the Digestive System
Crohn's disease usually causes inflammation in patches in the digestive system. The disease can occur anywhere along in the digestive system, from the mouth to the anus. However, from what we know about Crohn's and the digestive system, Crohn's disease is most often found near the end of the small intestine, in the colon, or in both.
Crohn's and the Digestive System: An OverviewIf you have Crohn's disease, your digestive system still works in the normal way to push food along as it's digested. However, the intestines have become irritated and inflamed. This inflammation usually happens in patches along the digestive tract, with "skip areas" of healthy tissue in between. This is different from ulcerative colitis (which is another type of inflammatory bowel disease) in which the inflammation is usually continuous. Unlike other types of inflammation that heal (known as acute inflammation), ulcerative colitis and Crohn's disease cause chronic inflammation, or inflammation that lasts for a long time and keeps on coming back.
Inflammation with Crohn's disease is also different than that seen with ulcerative colitis in that it occurs throughout the entire thickness of the affected bowel. With ulcerative colitis, the inflammation only occurs within the inner lining of the intestines. Because Crohn's disease affects the entire thickness of the bowel, certain complications are more common. These include:
- Fistulas, which are tunnel-like sores
- Bowel obstructions, which are narrowed sections of intestine that block the passage of food.
(Click Complications of Crohn's Disease for more information.)
Where Does Crohn's Disease Occur?Crohn's disease can develop anywhere along the digestive tract, from the inside of your mouth all the way to the anus. But, most commonly, it is found near the end of the small intestine (ileum) and/or in the colon. In fact, nearly half of all Crohn's disease cases involve both the small and large intestine. About 20 percent of cases are in the colon (large intestine) alone. About one-third affect the ileum alone. Lesions near the anus occur in about one-quarter to one-third of people with Crohn's disease, but are rarely the only site of Crohn's disease.
When just the end of the small intestine is affected, it can be called "ileitis" or "regional enteritis." When both the small intestine and the colon are involved, it's called "ileocolitis." And when only the colon is involved, it's called "Crohn's colitis" or "Crohn's disease of the colon."