What is Crohn’s disease?

Crohn’s disease is a chronic disease that causes inflammation and irritation in your digestive tract. Most commonly, Crohn’s affects your small intestine and the beginning of your large intestine. However, the disease can affect any part of your digestive tract, from your mouth to your anus. Learn more about your digestive system and how it works.

Crohn’s disease is an inflammatory bowel disease (IBD)Ulcerative colitis and microscopic colitis are other common types of IBD.

Crohn’s disease most often begins gradually and can become worse over time. You may have periods of remission that can last for weeks or years.

How common is Crohn’s disease?

Researchers estimate that more than half a million people in the United States have Crohn’s disease.1 Studies show that, over time, Crohn’s disease has become more common in the United States and other parts of the world.1,2 Experts do not know the reason for this increase.

Who is more likely to develop Crohn’s disease?

Crohn’s disease can develop in people of any age and is more likely to develop in people

  • between the ages of 20 and 292
  • who have a family member, most often a sibling or parent, with IBD
  • who smoke cigarettes

What are the complications of Crohn’s disease?

Complications of Crohn’s disease can include the following:

  • Intestinal obstruction.Crohn’s disease can thicken the wall of your intestines. Over time, the thickened areas of your intestines can narrow, which can block your intestines. A partial or complete intestinal obstruction, also called a bowel blockage, can block the movement of food or stool through your intestines.
  • In Crohn’s disease, inflammation can go through the wall of your intestines and create tunnels, or fistulas. Fistulas are abnormal passages between two organs, or between an organ and the outside of your body. Fistulas may become infected.
  • Inflammation that goes through the wall of your intestines can also lead to abscesses. Abscesses are painful, swollen, pus-filled pockets of infection.
  • Anal fissures.Anal fissures are small tears in your anus that may cause itching, pain, or bleeding.
  • Inflammation anywhere along your digestive tract can lead to ulcers or open sores in your mouth, intestines, anus, or perineum.
  • Malnutrition develops when your body does not get the right amount of vitamins, minerals, and nutrients it needs to maintain healthy tissues and organ function.
  • Inflammation in other areas of your body.You may have inflammation in your joints, eyes, and skin.

What other health problems do people with Crohn’s disease have?

If you have Crohn’s disease in your large intestine, you may be more likely to develop colon cancer . If you receive ongoing treatment for Crohn’s disease and stay in remission, you may reduce your chances of developing colon cancer.3

Talk with your doctor about how often you should get screened for colon cancer. Screening is testing for diseases when you have no symptoms. Screening for colon cancer can include colonoscopy with biopsies. Although screening does not reduce your chances of developing colon cancer, it may help to find cancer at an early stage and improve the chance of curing the cancer.


[1] Kappelman MD, Moore KR, Allen JK, Cook SF. Recent trends in the prevalence of Crohn’s disease and ulcerative colitis in a commercially insured U.S. population. Digestive Diseases and Sciences. 2013;58:519–525.

[2] Molodecky NA, Soon IS, Rabi DM, et al. Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systematic review. Gastroenterology. 2012;142(1):46–54.

[3] Burisch J, Munkholm P. Inflammatory bowel disease epidemiology. Current Opinion in Gastroenterology. 2013;29(4):357–362.

How can my diet help the symptoms of Crohn’s disease?

Changing your diet can help reduce symptoms. Your doctor may recommend that you make changes to your diet such as

  • avoiding carbonated, or “fizzy,” drinks
  • avoiding popcorn, vegetable skins, nuts, and other high-fiberfoods
  • drinking more liquids
  • eating smaller meals more often
  • keeping a food diary to help identify foods that cause problems

Depending on your symptoms or medicines, your doctor may recommend a specific diet, such as a diet that is

What are the symptoms of Crohn’s Disease?

The most common symptoms of Crohn’s disease are

Other symptoms include

  • anemia
  • eye redness or pain
  • feeling tired
  • fever
  • joint pain or soreness
  • nauseaor loss of appetite
  • skin changes that involve red, tender bumps under the skin

Your symptoms may vary depending on the location and severity of your inflammation.

Some research suggests that stress, including the stress of living with Crohn’s disease, can make symptoms worse. Also, some people may find that certain foods can trigger or worsen their symptoms.

What causes Crohn’s disease?

Doctors aren’t sure what causes Crohn’s disease. Experts think the following factors may play a role in causing Crohn’s disease.

Autoimmune reaction

One cause of Crohn’s disease may be an autoimmune reaction—when your immune system attacks healthy cells in your body. Experts think bacteria in your digestive tract can mistakenly trigger your immune system. This immune system response causes inflammation, leading to symptoms of Crohn’s disease.


Crohn’s disease sometimes runs in families. Research has shown that if you have a parent or sibling with Crohn’s disease, you may be more likely to develop the disease. Experts continue to study the link between genes and Crohn’s disease.

Other factors

Some studies suggest that other factors may increase your chance of developing Crohn’s disease:

  • Smoking may double your chance of developing Crohn’s disease.4
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirinor ibuprofen ,5 antibiotics,6 and birth-control pills 6 may slightly increase the chance of developing Crohn’s disease.
  • A high-fat diet may also slightly increase your chance of getting Crohn’s disease.7

Stress and eating certain foods do not cause Crohn’s disease.


[4] Ghazi LJ. Crohn’s Disease. Medscape website. http://emedicine.medscape.com . Updated February 26, 2015. Accessed May 6, 2016.

[5] Ananthakrishnan AN, Higuchi LM, Huang ES, et al. Aspirin, nonsteroidal anti-inflammatory drug use, and risk for Crohn’s disease and ulcerative colitis: a cohort study. Annals of Internal Medicine. 2012;156(5):350–359.

[6] Ko Y, Butcher R, Leong RW. Epidemiological studies of migration and environmental risk factors in the inflammatory bowel diseases. World Journal of Gastroenterology. 2014;20(5):1238–1247.

[7] Hou JK, Abraham B, El-Serag H. Dietary intake and risk of developing inflammatory bowel disease: a systematic review of the literature. American Journal of Gastroenterology. 2011;106(4):563–573.