What are the different types of Crohn's disease?

There are five different types of Crohn's disease, depending on location. By far, the most common location for Crohn's disease is in the terminal ileum (the last part of the small bowel). In fact, historically, it used to be called terminal ileitis. About 35% of people with Crohn’s disease will have only terminal ileal involvement. However, another 35% of people will have disease that's limited to both their small bowel as well as the first third of their colon.

About 20% of people will have Crohn's colitis, which means it involves only the colon, not the small bowel.

About 10% of people have Crohn's disease that involves the proximal gastrointestinal tract, which includes the upper part of the ileum, the jejunum (the middle section of the small bowel), the stomach or the duodenum (the first part of the small bowel). This can also represent a very aggressive form of Crohn's disease that oftentimes requires more aggressive treatments to get under control.

Additionally, up to 30% of people with Crohn’s disease at other locations can also develop perianal disease, which comprises abnormal connections from the last part of the colon, the rectum, to the outer part of the skin around the anus with fistulas. These abnormal connections from either deep ulcerations or active disease can burrow through the rectum, through the muscles and the fat around the rectum, and can lead to the formation of abscesses as well as fistulas. Often, treatment requires a combination approach with surgery, antibiotics and medications.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.