Crohn's Disease

Overview | Diagnosis and Tests | Management and Treatment | Outlook / Prognosis | Resources

What is Crohn's disease?

Crohn's disease is a chronic (long-term) illness in which the intestine (bowel) becomes inflamed and ulcerated (marked with sores). Along with ulcerative colitis, Crohn's disease is part of a group of diseases known as inflammatory bowel disease (IBD).

Crohn's disease most commonly affects the lower part of the small intestine (ileum), although it can occur in any part of the large or small intestine, stomach, esophagus (“food pipe”), or even the mouth. It can occur at any age, but it is most common between the ages of 15 and 30.

Crohn's disease can interfere with the normal function of the bowel in a number of ways. The bowel tissue may:

  • Swell, thicken, or form scar tissue, which can lead to blockage of the passageway inside the bowel.
  • Develop ulcers that can involve the deep layers of the bowel wall.
  • Lose its ability to absorb nutrients from digested foods (malabsorption).
  • Develop abnormal passageways (fistulas) from one part of the bowel to another part of the bowel, or from the bowel to nearby tissues such as the bladder or vagina, or even the skin.

What causes Crohn's disease?

The cause of Crohn's disease is unknown. It is believed that many factors cause an abnormal response of the immune system in the gastrointestinal tract.

Genetics (heredity) has been found to play a role in the disease process. First-degree relatives (mother, father, sister, or brother) of patients with IBD are about three to 20 times more likely to develop the disease than the general population. Having a sibling with Crohn's disease can increase the risk of having the disease by 30 times compared with the general population. Children who have one parent with Crohn's disease, and Jewish people of European descent, also have a greater risk for developing the disease.

What are the symptoms of Crohn's disease?

People with Crohn's disease go through periods of severe symptoms followed by periods of remission (no symptoms, or milder symptoms) that can last for weeks or years. Unfortunately, there is no way to tell when a remission will occur or when symptoms will return.

The symptoms of Crohn's disease depend on where in the bowel the disease occurs and how severe it is. In general, symptoms can include:

Other symptoms can develop, depending on the complications of the disease. For example, a person with a fistula (abnormal passageway) in the rectal area may have pain and discharge around the rectum. Other complications from Crohn's disease include:

Diagnosis and Tests

How is Crohn's disease diagnosed?

A number of tests are used to diagnose Crohn's disease. First, your doctor will review your medical history. This information is helpful because Crohn's disease is more common in people who have a first-degree relative with IBD. After the physical examination is complete, the doctor may order the following tests:

  • Endoscopy (such as colonoscopy or sigmoidoscopy): A flexible, lighted tube (called an endoscope) is inserted into the rectum to view the inside of the rectum and colon. (Colonoscopy shows a greater portion of the colon than sigmoidoscopy.) A small sample of tissue may also be taken for testing (biopsy).
  • Blood tests: The doctor will look for signs of anemia, or a high white blood cell count, which will mean that there is inflammation or an infection somewhere in the body.
  • Barium X-ray (barium enema or small bowel series): X-rays are taken of either the upper or lower intestine. Barium coats the lining of the small intestine and colon, and shows up as white on an X-ray, which allows the doctor to see any abnormalities.
  • CT scan: X-ray of the abdomen that shows how widespread the inflammation is, and how severe it is. It also identifies lesions in other organs.

Management and Treatment

How is Crohn's disease treated and managed?

Treatment for Crohn's disease depends on how severe the disease is, and where it is located. Because the disease can sometimes go into remission on its own, it is not always possible to determine whether a specific treatment has been effective. When Crohn's disease is active, treatment is aimed at controlling inflammation, correcting shortages in the patient’s diet, and relieving symptoms such as pain, diarrhea, and fever.

Medications are generally the first step in treating Crohn's disease. Some of these medications include anti-inflammatories, antibiotics, corticosteroids, antidiarrheals, and medications that suppress the immune system. For those patients who have nutritional shortages, supplements are often prescribed.

Even though it cannot cure Crohn's disease, surgery is sometimes needed for patients whose symptoms do not respond to medications. Surgery can correct perforations (holes), blockages, or bleeding in the intestine. Unfortunately, Crohn's disease often returns to the area next to where the inflamed part was removed. You should discuss with your doctor all possible options before deciding upon surgery.

In managing Crohn's disease, it is very important to maintain a healthy lifestyle, even when the disease goes into remission for long periods of time. You can do this by exercising regularly and eating a healthy diet. If you smoke, quitting can also help prevent symptoms from coming back. Studies have shown that smokers are at a higher risk of developing Crohn's disease than non-smokers, and that smokers with Crohn's disease tend to have a more severe course than non-smokers with Crohn's disease.

Outlook / Prognosis

What is the outlook for Crohn's disease?

People with Crohn's disease are usually able to lead healthy and active lifestyles. Like many other disorders, understanding and education is the most important tool with which to manage and prevent complications.


Where can I go for more information?

The following organizations can provide more information about Crohn's disease:

Crohn's and Colitis Foundation of America, Inc.

733 Third Avenue, Suite 510

New York, NY 10017


National Institute of Diabetes and Digestive and Kidney Diseases


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 02/16/2016