Crohn's Disease



Crohn disease is a 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. Early treatment can lower the risk of complications, such as intestinal obstruction.

Small Intestine
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The cause of this problem is not known. Some things that may play a role are genetics, the environment, and problems with the immune system.

Risk Factors

The risk of this problem is higher in people with Ashkenazi Jewish ancestry. Other things that may raise the risk are:

  • Having other family members with the disease
  • Tobacco use disorder
  • Lack of activity
  • Stress-related disorder
  • Certain medicines, such as antibiotics and nonsteroidal anti-inflammatory drugs
  • Certain infections, such as salmonella or campylobacter gastroenteritis



Problems may be:

  • Diarrhea
  • Belly cramps and pain
  • Rectal bleeding
  • Weight loss
  • Weakness and lack of energy
  • Nausea
  • Fever
  • Mouth sores
  • Sores in the anal area


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

Blood and stool tests will be done to look for signs of the disease.

Images will be taken to look at the intestines and surrounding structures. This can be done with:

  • Upper gastrointestinal series
  • Lower gastrointestinal series
  • Flexible sigmoidoscopy
  • Colonoscopy
  • CT scan
  • MRI scan
  • Ultrasound
  • X-ray

A biopsy may be taken during some of these tests. A biopsy is a sample of the intestinal tissue that can be examined under a microscope.



There is no cure. The goal of treatment is to manage symptoms. Choices are:

  • Dietary changes, such as avoiding foods that trigger symptoms
  • Medicines, such as:
    • Aminosalicylate medications such as sulfasalazine, mesalamine, and olsalazine
    • Anti-inflammatory medications such as prednisone, methylprednisolone, and budesonide
    • Immune modifiers such as azathioprine, 6-mercaptopurine (6MP), and methotrexate
    • TNF inhibitors such as infliximab, adalimumab, and certolizumab
    • Antibiotics such as metronidazole, ampicillin, and ciprofloxacin

People who are not helped by these methods may need surgery. The diseased part of the intestine may be removed. The two healthy ends will be joined together.


There are no known methods to prevent this health problem.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (CD; Regional Enteritis)


Crohn's & Colitis Foundation 

National Institute of Diabetes and Digestive and Kidney Diseases 


Crohn's and Colitis Canada 

Health Canada 


Crohn disease. Merck Manual Professional Version website. Available at: Accessed March 16, 2021.

Crohn disease in adults. EBSCO DynaMed website. Available at: Accessed March 16, 2021.

Crohn's disease. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: Accessed March 16, 2021.

Lichtenstein GR, Loftus EV, et al. ACG Clinical Guideline: Management of Crohn's Disease in Adults. Am J Gastroenterol. 2018 Apr;113(4):481-517.

What is Crohn's disease? Crohn's & Colitis Foundation website. Available at: Accessed March 16, 2021.