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What is Crohn's Disease?

Crohn’s disease is an autoimmune disease of the digestive tract. Your body’s immune system should protect your body from sicknesses. But in Crohn’s disease, your immune system attacks the digestive tract by mistake.

Crohn’s disease causes patches of inflammation (swelling) that can affect any part of the digestive tract, from the mouth to the anus. It most often affects the lower part of the small intestine. The swelling spreads deep into the lining of the tissue.

Crohn’s disease can get worse over time. Some people may develop complications like these:

  • Bowel obstruction. Crohn’s disease can thicken the wall of your intestine and block the flow of waste.
  • Sores (ulcers). Crohn’s disease can cause open sores anywhere along your digestive tract. Sometimes the sores break all the way through the tissue and into surrounding organs. This can cause serious problems.
  • Nutrition problems. People with Crohn’s disease often want to eat less and have trouble getting good nutrition.


Symptoms of Crohn’s disease may include:

  • Abdominal (belly) pain and cramping
  • Diarrhea
  • Bleeding from the rectum or blood in the stool
  • Decreased appetite and weight loss

Symptoms of serious Crohn’s disease may also include fever, tiredness, eye redness, constipation, joint pain, or rectal pain. Symptoms can also come and go. You may have long periods with no symptoms at all.

When to See a Doctor

See your doctor if you have:

  • Continued changes in bowel movements
  • Severe abdominal or rectal pain
  • Blood in your stool
  • Ongoing diarrhea that does not respond to over-the-counter medicines
  • Weight loss
  • Fever


Doctors don’t know exactly what causes Crohn’s disease. But they do know that certain things give people a greater chance of getting it. These include:

  • Age. Most people first get it between the ages of 20 and 30 years. But, a person can get it at any age — even in childhood.
  • Family history. About 20 out of 100 people with Crohn’s disease have a parent, brother, or sister with the same disease.
  • Race or ethnicity. White people have a greater chance of getting Crohn’s disease than people of other races. Also, people of Ashkenazi Jewish descent have a greater chance of getting the disease.
  • Where you live. You have a greater chance of getting Crohn’s disease if you live in a city, in a developed country, and in a northern climate.
  • Certain medicines, such as steroids. Isotretinoin (Accutane) is a steroid medicine used to treat acne. Some studies show people who use it get Crohn’s disease more often.
  • Smoking. Smoking will make your Crohn’s disease more serious and make you more likely to need surgery. If you smoke, quit.

Diagnosis and Tests

Your doctor may use a few tests to find out if you have Crohn’s disease. These may include:

  • Blood tests to check for anemia and make sure your cells are getting enough oxygen.
  • A stool sample test to see if there is bleeding or infection in your intestines.
  • A colonoscopy so the doctor can look at the inside of your intestine and see if the tissue is inflamed (swollen). The doctor can also take a tissue sample (biopsy) to send to a laboratory for testing.


Doctors can treat the symptoms of Crohn’s disease, but there is no known cure for it. Treatments can reduce inflammation and relieve other symptoms such as diarrhea and bleeding. Treatment can sometimes stop your symptoms for long periods of time. Treatments may include:

  • Medicines. Most people are treated with medicines to reduce inflammation. Some patients may also be treated with medicines that keep the immune system from attacking the digestive tract. Other medicines may be used to treat infections or diarrhea.
  • Food and nutrition. Your doctor may recommend special nutrition supplements for a short time. If your digestive system needs to rest, you may be given nutrition through a feeding tube or directly into a vein. Your doctor may also recommend changing your diet. This might include:
    • Eating a high-calorie, high-protein diet to prevent malnutrition and weight loss. Specific food choices don’t appear to make most symptoms better.
    • Avoiding whole grains, spices, alcohol, and milk products when you have diarrhea and cramping.
  • Surgery. If medicines don’t control your symptoms, you may need surgery. About 2 out of every 3 patients with Crohn’s disease will need surgery at some point. Crohn’s disease can still come back after surgery, however. Different types of surgeries include:
    • Bowel resection, which removes a diseased part of the large intestine (or colon).
    • Colectomy, which removes the entire colon.
    • Other surgeries, which can be done to correct problems in the intestines like blockages, tears, areas full of pus, or bleeding.


We do not know what causes individuals to develop Crohn’s disease, so we are still determining the best course of prevention. However, eating a healthy diet and making smart choices about medications may reduce your risk of Crohn’s disease.