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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Crohn's is a severe, chronic inflammatory bowel disease. It causes inflammation, ulcers, and bleeding in the digestive tract. It usually affects the end portion of the small intestine called the ileum. However, any part of the digestive tract can be affected, from the mouth to the anus.

Small Intestine

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The cause of Crohn's disease is not known. Inflammatory bowel diseases (eg, ulcerative colitis and Crohn's disease) seem to run in some families. Some researchers think that it is due to a reaction to a virus or bacteria. The immune system overreacts and causes damage to the intestines.

Risk Factors

Factors that increase your chance of getting Crohn's include:

  • Family members with inflammatory bowel disease
  • Jewish heritage
  • A diet that is high in fat, sugar, and meat


Symptoms include:

  • Diarrhea
  • Abdominal cramps and pain
  • Rectal bleeding
  • Weight loss
  • Fatigue, weakness
  • Nausea
  • Fever
  • Mouth sores
  • Sores, abscesses in the anal area


The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include:

  • Your bodily fluids and waste products may need to be tested. This can be done with:
    • Blood tests
    • Stool tests
  • Pictures of your bodily structures may need to be taken. This can be done with:
  • Your rectum and colon may need to be examined. This can be done with:
  • Tissue samples of your colon may need to be taken. This can be done with biopsy.

If you are diagnosed with Crohn's disease, follow your doctor's instructions.


Treatment may include:

Your doctor may recommend that you avoid foods that trigger symptoms. These foods are different for each person. They may include:

  • Dairy foods due to lactose intolerance
  • Highly seasoned foods
  • High-fiber foods

There are many types of medicines that are used to treat Crohn's disease. Examples of these medicines include:

  • Aminosalicylate medicines—Such as sulfasalazine, mesalamine, olsalazine
  • Anti-inflammatory medicines—Such as prednisone, methylprednisolone, budesonide
  • Immune modifiers—Such as azathioprine, 6-mercaptopurine, methotrexate
  • TNF inhibitors—Such as infliximab, adalimumab, etanercept, certolizumab, golimumab
  • Antibiotic medicines—Such as metronidazole, ampicillin, ciprofloxacin

Very severe Crohn's may not improve with medicines. You may be advised to have the diseased section of your intestine removed. The two remaining healthier ends of the intestine are then joined together. You are still at high risk for the disease returning.

Surgery may also be done if you have an obstruction or fistulas.

Untreated Crohn's disease may lead to:

  • Fistulas—Abnormal connections between the intestine and other organs or tissues, such as the bladder, vagina, or skin
  • Intestinal obstruction
  • Arthritis
  • Eye inflammation
  • Liver disease
  • Kidney stones
  • Gallstones
  • Skin rashes
  • Osteoporosis


Women may be able to reduce their risk of Crohn's disease through exercise. Talk to your doctor about an exercise program that is best for you.


American Gastroenterological Association


Crohn's and Colitis Foundation of America



Crohn's and Colitis Foundation of Canada



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11/25/2013 DynaMed's Systematic Literature Surveillance. http://www.ebscohost.com/dynamed: Khalili H, Ananthakrishnan A, et al. Physical activity and risk of inflammatory bowel disease: prospective study from the Nurses' Health Study cohorts. BMJ 2013;347:f6633.

Last reviewed September 2012 by Daus Mahnke, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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