Crohn's Disease

Crohn's disease causes inflammation of the small intestine. Although it may involve any part of the digestive tract from the mouth to the anus, it most commonly affects the last part of the small intestine, called the ileum, and the large intestine, including the colon and rectum. This is considered a chronic condition because it may recur at various times throughout your lifetime, with periods of remission in which you are free of symptoms. There is no consistently accurate way to predict when a remission may occur or when symptoms will return.

The disease may occur in people of all ages, although most are diagnosed before the age of 30. However, it also can affect young children and older people in their seventies or beyond. Crohn's disease occurs most commonly in people living in northern climates and affects men and women equally. The condition can be inherited and is common in some families. About 20 percent to 25 percent of those with Crohn's disease have a close relative who also has the disease or the related condition, ulcerative colitis. The cause of Crohn's disease has not been proven definitely. However, the immune system's response to certain viruses and bacteria that cause inflammation of the intestines is believed to be the primary cause of the disease.

Common symptoms of Crohn's disease include the following:

  • Loose, watery or frequent bowel movements
  • Abdominal cramps and pain
  • Fever
  • Rectal bleeding
  • Loss of appetite and subsequent weight loss

During periods of active symptoms, you also may experience:

  • Fatigue
  • Joint pain
  • Skin problems
  • Fissures, or tears in the lining of the anus
  • Fistulas, a tunnel that connects the intestine to the bladder, vagina or skin
  • Oral or skin lesions

First your doctor will ask about your medical history and perform a physical evaluation. There is no single test that can provide a diagnosis of Crohn's disease, but rather a series of X-rays, laboratory tests, endoscopy and pathology tests that are used. These may include the following:

  • Blood Tests: Blood tests may be done to check for anemia, which may indicate bleeding in the intestines. Blood tests also may uncover a high white blood cell count, which is a sign of inflammation somewhere in the body. C reactive protein, a marker of inflammation, also may be elevated.
  • Stool Sample: By testing a stool sample, the doctor can tell if there is bleeding or infection in the intestines.
  • Small Bowel Radiograph: Your doctor may perform a small bowel follow through to look at the small intestine. For this test, you will drink barium, a chalky solution that coats the lining of the small intestine, before X-rays are taken. The barium and irregularity of the border between the barium and intestine shows up white on X-ray film, revealing inflammation or other abnormalities in the intestine.
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Although there is no cure for Crohn's disease, there are a number of treatment options available.

Drug Therapy

Drugs are used to suppress the inflammatory response associated with Crohn's disease, which in turn helps the intestines to heal and relieves symptoms. Once symptoms are under control, medications are used to decrease the frequency of flare-ups and prevent symptoms from recurring. There are several types of drugs available to treat Crohn's disease including aminosalicylates, corticosteroids, immune modifiers and biologic therapy.

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UCSF Clinics & Centers


Colitis and Crohn's Disease Center
1701 Divisadero St., Suite 120
San Francisco, CA 94115
Phone: (415) 353-7921
Fax: (415) 502-2249
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Gastroenterology at Mount Zion
1701 Divisadero St., Suite 120
San Francisco, CA 94115
Phone: (415) 502-4444
Fax: (415) 502-2249
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Gastroenterology at Parnassus
350 Parnassus Ave., Suite 410
San Francisco, CA 94143
Phone: (415) 502-2112
Fax: (415) 514-3300
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Gastrointestinal Motility & Secretion Center
1701 Divisadero St., Suite 120
San Francisco, CA 94115
Phone: (415) 502-4444
Fax: (415) 502-2249
Appointment information