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Quick Facts

Crohn Disease


The Manual's Editorial Staff

Last full review/revision Jan 2020| Content last modified Jan 2020
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Your digestive tract is the path that food takes through your body after you eat it. Food goes from your mouth (eating) to your anus (passing stool). Your intestine is the long tube in your digestive system that connects your stomach to your anus. It digests food and absorbs nutrients.

You have a small intestine and a large intestine. The small intestine, or small bowel, is very long with many coils. The large intestine, also called the colon or large bowel, is shorter and wider.

What is Crohn disease?

Crohn disease is long-term inflammation in your intestines. Intestines are also called "bowels," so Crohn disease is one of the two diseases called inflammatory bowel disease. The other inflammatory bowel disease is ulcerative colitis.

Crohn disease usually affects the small intestine. But it can affect the large intestine or both the small and large intestines.

  • Crohn disease is an inflammatory bowel disease

  • The cause isn't known, but it may be due to a problem with your immune system

  • Symptoms come and go and can include diarrhea, crampy pain in your belly, fever, not feeling hungry, and weight loss

  • Doctors use a colonoscopy and imaging tests to diagnose Crohn disease

  • There's no cure for Crohn disease, but treatment with medicines and sometimes surgery can decrease the symptoms

What causes Crohn disease?

Doctors don't know what causes Crohn disease. It may be a problem with your immune system that causes your intestine to overreact and become inflamed.

The risk of Crohn disease is increased if you:

  • Have people in your family with the disease

  • Are Jewish and your family comes from Eastern Europe

  • Smoke

  • Are a woman and take birth control pills

What are the symptoms of Crohn disease?

Symptoms come and go. Usually symptoms are severe for a few days or weeks and then go away or at least get better for a while. For most people, symptoms continue to flare up on and off throughout their life.

The most common symptoms in adults include:

  • Diarrhea, which is sometimes bloody

  • Crampy belly pain

  • Fever

  • No appetite

  • Weight loss

If a flare up is severe, you may have:

If you have Crohn disease for a long time, you can have:

  • Skin rash

  • Joint pain and swelling

  • Red eyes

  • Liver and gallbladder problems

  • Sores on your anus, and sometimes anal fissures

  • Increased risk of cancer in your intestine

Children can have belly pain, diarrhea, and fever, but they can also have:

  • Slow growth

  • Swollen joints

  • Fatigue (feeling weak and tired all over)

How can doctors tell if I have Crohn disease?

Doctors do tests depending on your symptoms and how suddenly they come on:

  • Sudden, severe belly pain: CT scan or MRI of your belly

  • Off and on belly pain for a while: Sometimes, x-rays or CT scan of your belly after you drink a liquid that shows up parts of the intestine, or swallowing a special capsule with a tiny camera that takes pictures as it passes through your digestive tract

  • Diarrhea: Looking in your colon with colonoscopy (a doctor threads a thin, lighted tube with a small camera through your anus to look at your intestines)

Doctors will also do blood tests. Blood tests can't diagnose Crohn disease but can tell if you have certain complications.

When Crohn disease affects only the large intestine, it is sometimes hard for doctors to tell the difference between Crohn disease of the colon and ulcerative colitis because many of the symptoms are the same.

How do doctors treat Crohn disease?

There's no cure for Crohn disease. Treatments can help reduce the inflammation and relieve symptoms.

Medicines may:

  • Help stop diarrhea and belly pain

  • Lessen inflammation in your intestine

  • Change the way your immune system works

Doctors may suggest special fluids that have extra nutrients in them, especially for children with slow growth.

Doctors will also ask you to:

  • Quit smoking because people who smoke are more likely to have their symptoms come back after treatment

  • Drink plenty of fluids

  • Take nutrients such as iron, calcium, and vitamin D supplements

  • Avoid nuts and raw fruits and vegetables when you have a flare-up

  • Try a dairy-free diet to see if it eases symptoms

  • Not take certain medicines that can cause a flare-up, such as painkillers called NSAIDs

  • Avoid stress

Most people with Crohn disease need surgery at some point. In this surgery, doctors remove part of your intestine. This helps with symptoms. Half of the people who have surgery need a second surgery later.

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