Common Complications of Crohn's Disease

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Learning you have Crohn's disease can be overwhelming. It can be difficult not knowing how your condition will progress and what problems you may need to manage. Understanding the possible complications of the disease and how to act on them can help you take control and feel better faster.

Below are the most common complications of Crohn's disease. Although many of these complications can't be treated without your doctor's help, it's important to recognize them so you can call your doctor right away. The faster you seek treatment, the sooner you'll get relief.

Blockage of the Intestine

Crohn's disease can cause severe inflammation in portions of the small intestine. This inflammation can lead to swelling and the development of scar tissue, which can narrow or block the passageway that allows digested food to progress through the bowel. The blockage can cause symptoms such as cramping pain in the abdomen, bloating, and sometimes vomiting.

If you experience a blockage, your doctor may prescribe medication to help reduce the inflammation that is causing it. Surgery may be necessary if medications don't work.  


About one in every three people with Crohn's disease will develop a fistula. Fistulas are abnormal passageways that connect two parts of the bowel together. They can also connect the bowel to the bladder, vagina, or outside skin. Fistulas occur when severe inflammation spreads through the bowel wall, creating a tunnel to another area.

Symptoms of a fistula can differ depending on where the tunnel formed. An internal fistula may cause general symptoms such as diarrhea or malnourishment because food is bypassing a section of the bowel and is unable to be absorbed. Fistulas connecting the bowel to other areas may produce more specific symptoms. For example, a fistula between the intestine and the skin may cause leaking of mucus, pus, or stool from the area.

Pay close attention to your body and talk with your doctor if you have unexplained symptoms. Your doctor can help close a fistula, reducing or eliminating related symptoms. Treatment often involves medication and sometimes surgery.  


Sometimes fistulas form an abscess, or collection of pus, near the intestine. This hollow pocket of infection may cause fever and a general feeling of unwellness. If you experience these flulike symptoms, talk with your doctor. An abscess can be drained either by needle or catheter, or it may require surgery.


Many people with Crohn's disease suffer from malnourishment. The disease itself can cause a loss of appetite, reducing the number of overall calories and nutrients taken in. Plus, inflammation or surgery in the small intestine can interfere with the absorption of nutrients into the body.

To ensure you are getting the nutrients you need, talk with your doctor or a dietitian about a healthy eating plan. If you're unable to get enough vitamins and minerals from your diet, you may need to take supplemental vitamin injections or pills.

Non-Intestinal Complications

Crohn's disease can also cause other issues not related to the intestines, such as lesions in the mouth and arthritis. In fact, about 25 percent of people with Crohn's disease develop arthritis, which involves inflammation or swelling of the joints. Crohn's disease also increases the risk for low bone density problems such as osteoporosis. Both of these issues, including prevention and treatment, can be discussed with your doctor.   

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jul 27

  1. Arthritis. Crohn’s and Colitis Foundation of America.

  2. Bone Loss in IBD. Crohn’s and Colitis Foundation of America. 

  3. What is Crohn’s Disease? Crohn’s and Colitis Foundation of America.

  4. Diet and Nutrition. Crohn’s and Colitis Foundation of America.

  5. Living with a Fistula. National Association for Colitis and Crohn’s Disease.

  6. Surgery for Crohn’s Disease & Ulcerative Colitis. Crohn’s and Colitis Foundation of America.

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