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Crohn's Disease

Crohn's Disease

Condition Basics

What is Crohn's disease?

Crohn's disease is a lifelong inflammatory bowel disease (IBD). In Crohn's disease, parts of the digestive system get swollen and have deep sores called ulcers. This can result in symptoms such as belly pain and diarrhea.

Crohn's disease in part of the digestive tract

Crohn's disease can affect any part of the digestive tract (which goes from the mouth to the anus). Most common is Crohn's disease that affects the ileum (the part of the small intestine that joins the large intestine). But Crohn's disease can be in multiple places in the digestive tract at the same time.

This picture shows Crohn's disease that is affecting the ileum and parts of the large intestine (colon), including the rectum. This kind of disease pattern is called ileocolitis.

What causes it?

Doctors don't know what causes Crohn's disease. You may get it when the body's immune system has an abnormal response to normal bacteria in your intestine. Other kinds of bacteria and viruses may also play a role in causing the disease.

What are the symptoms?

The main symptoms of Crohn's disease are belly pain and diarrhea (sometimes with blood). Some people may have diarrhea 10 to 20 times a day. Losing weight without trying is another common sign. You may have only mild symptoms or go for periods of time without symptoms. A few people have ongoing, severe symptoms.

How is it diagnosed?

Your doctor will ask you about your symptoms and do a physical exam. You may also have X-rays and lab tests to find out if you have Crohn's disease. You may have tests that look inside the colon, and you may have a biopsy.

How is Crohn's disease treated?

The main treatment for Crohn's disease is medicine. Mild symptoms may be treated with nonprescription medicines to stop diarrhea. You may also use prescription medicines to treat and prevent symptoms. Your treatment will depend on your symptoms and how bad they are. Exercise, eat healthy meals, and don't smoke to help yourself feel better.


Doctors don't know what causes Crohn's disease. You may get it when the body's immune system has an abnormal response to normal bacteria in your intestine. Other kinds of bacteria and viruses may also play a role in causing the disease.

Crohn's disease can run in families. Your chances of getting it are higher if a close family member has it. People of Eastern European (Ashkenazi) Jewish background may have a higher chance of getting Crohn's disease. Smoking also puts you at a higher risk for the disease.


The main symptoms of Crohn's disease are belly pain and diarrhea (sometimes with blood). Some people may have diarrhea 10 to 20 times a day. Losing weight without trying is another common sign.

Less common symptoms include mouth sores, bowel blockages, anal tears (fissures), and openings (fistulas) between organs.

Infections, hormonal changes, smoking, medicines, and lifestyle changes can cause your symptoms to flare up. You may have only mild symptoms or go for long periods of time without any symptoms. A few people have ongoing, severe symptoms.

What Happens

Crohn's disease is an ongoing (chronic) condition that may flare up throughout your life. It affects different people in different ways. Some people may have only mild symptoms. Others may have severe symptoms or problems caused by Crohn's that, in rare cases, may be life-threatening.

Things that may cause Crohn's disease symptoms to flare up include medicines, infections, hormonal changes, lifestyle changes, and smoking.

The disease can also go into remission. This means that it is not active and you have no symptoms.

Complications of Crohn's disease

Crohn's disease may cause sores, or ulcers, that tunnel through the intestine and into the nearby tissue. These are often around the anus and rectum. These tunnels, called fistulas, are a common problem with Crohn's disease. They may get infected. Crohn's disease can also cause anal fissures. These are narrow tears that extend from the muscles that control the anus (anal sphincters) up into the anal canal.

In long-term Crohn's disease, scar tissue may replace some of the inflamed or ulcerated intestines. This scar tissue can form blockages (bowel obstructions) or narrowed areas (strictures). These can prevent stool from passing through the intestines. Blockages in the intestines also can be caused by inflammation and swelling, which may improve with medicines. Sometimes blockages can only be treated with surgery.

Sometimes symptoms of Crohn's disease develop outside the digestive tract in other parts of the body. This can include in the eyes, liver, blood, and bones.

When to Call

Call a doctor now if you have been diagnosed with Crohn's disease and you have one or more of the following:

  • Fever or shaking chills
  • Lightheadedness, passing out, or rapid heart rate
  • Stools that are almost always bloody
  • Severe dehydration
  • Severe belly pain or severe pain and bloating
  • Evidence of pus draining from the area around the anus, or pain and swelling in the anal area
  • Repeated vomiting
  • Not passing any stools or gas

If you have any of these symptoms and you have been diagnosed with Crohn's disease, your condition may have become much worse. Some of these symptoms also may be signs of toxic megacolon. This is a rare complication of Crohn's disease that requires emergency treatment. Without treatment, it can cause the colon to leak or rupture, which can be fatal.

People who have Crohn's disease usually know their normal pattern of symptoms. Call your doctor if there is a change in your usual symptoms or if:

  • Your symptoms become significantly worse than usual.
  • You have diarrhea that lasts for more than 2 weeks.
  • You have lost weight.

Exams and Tests

Your doctor will ask you about your symptoms and do a physical exam. You may also have X-rays and lab tests to find out if you have Crohn's disease.

Tests that may be done to diagnose or evaluate Crohn's disease include:

  • A biopsy. The doctor takes a sample of tissue and tests it to find out if you have Crohn's disease or another disease, such as cancer.
  • Barium X-rays of the small intestine or colon.
  • Colonoscopy or flexible sigmoidoscopy. In these tests, the doctor uses a thin, lighted tube to look inside the colon.
  • Stool analysis. This test looks for blood and signs of infection in a sample of your stool.
  • One or more imaging tests, such as a CT scan or MRI.

Learn more


Treatment Overview

Your treatment will depend on the type of symptoms you have and how bad they are.

Medicines are the most common treatment for Crohn's disease. Medicines can control or prevent inflammation in the intestines and help relieve symptoms. They also promote the healing of damaged tissues.

People who have more severe, long-lasting symptoms may need other treatments. These can include stronger or different medicines, surgery to remove part of the intestine, or a procedure called balloon dilation.


  • Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine. You will get more details on the specific medicines your doctor prescribes.
  • Do not take anti-inflammatory medicines, such as aspirin, ibuprofen (Advil, Motrin), or naproxen (Aleve). They may make your symptoms worse. Do not take any other medicines or herbal products without talking to your doctor first.
  • Avoid foods that make your symptoms worse. These might include milk, alcohol, high-fiber foods, or spicy foods.
  • Eat a healthy diet. Make sure to get enough iron. Rectal bleeding may make you lose iron. Good sources of iron include beef, lentils, spinach, raisins, and iron-enriched breads and cereals.
  • Drink liquid meal replacements if your doctor recommends them. These are high in calories and contain vitamins and minerals. Severe symptoms may make it hard for your body to absorb vitamins and minerals.
  • Do not smoke. Smoking makes Crohn's disease worse. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
  • Seek support from friends and family to help cope with Crohn's disease. The illness can affect all parts of your life. Get counseling if you need it.


Medicines usually are the treatment of choice for Crohn's disease. They can control or prevent inflammation in the intestines. They help to:

  • Relieve symptoms.
  • Promote healing of damaged tissues.
  • Put the disease into remission. And they can keep it from flaring up again.
  • Postpone the need for surgery.

They include:

  • Aminosalicylates. Your doctor may recommend these medicines during a flare-up or at other times.
  • Antibiotics. These may treat the disease itself or infections that can occur with Crohn's disease.
  • Biologics. Your doctor may have you try these medicines if other medicines for Crohn's disease haven't worked for you.
  • Corticosteroids. They usually stop symptoms and put the disease in remission. But they aren't used as long-term treatment to keep symptoms from coming back.
  • Immune modulators. You may take these if other medicines don't work, if your symptoms come back when you stop taking steroid medicines, or if your symptoms come back often, even with treatment.


Surgery for Crohn's disease may be done if:

  • No medicine can control your symptoms.
  • You have serious side effects from medicines.
  • Your symptoms can only be controlled with long-term use of corticosteroids.
  • You have complications.

When surgery for Crohn's is needed, it involves removing the diseased part of the intestine. As little of the intestine as possible is removed to keep the intestines working normally. The disease tends to return to other areas of the intestines after surgery.

Learn more


Supplemental Nutrition

Some people who have Crohn's disease need extra nutrition because severe disease prevents their small intestine from absorbing nutrients.

Liquid feedings may be done through a tube placed in the nose and down into the stomach or through a vein. Feedings may be needed when:

  • Crohn's disease isn't controlled with standard treatment.
  • Short bowel syndrome occurs. This happens when so much of the small intestine has been surgically removed or is affected by the disease that you can't properly digest food and absorb enough nutrients.
  • Bowel blockage occurs.

Supplemental feeding can restore good nutrition to children who are growing more slowly than normal. It also can build strength if you need surgery or have been weakened because of severe diarrhea and poor nutrition.

Supplemental feeding allows the intestines to rest and heal. But it's common for symptoms to return when you go back to a regular diet.

Learn more


Current as of: September 8, 2021

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Arvydas D. Vanagunas MD - Gastroenterology

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