Medically reviewed on Feb 5, 2018
What Is It?
Crohn's disease is an inflammatory bowel disease in which inflammation injures the intestines. It is a long-term (chronic) condition. Crohn's disease typically begins between ages 15 and 40.
No one knows for sure what triggers the initial intestinal inflammation at the start of Crohn's disease. A viral or bacterial infection may start the process by activating the immune system in the intestine. However, the immune system attack is not turned off: it stays active and creates inflammation even after the infection goes away.
Certain genes passed on from parent to child increase the risk of developing Crohn's disease, if the right trigger occurs.
Once Crohn's disease begins, it can cause lifelong symptoms that come and go. The inner lining of the intestine thickens, and can wear away. The deeper layers of the intestine also become inflamed. This creates ulcers, cracks and fissures. Inflammation can allow an abscess (a pocket of pus) to develop.
A common complication of Crohn's disease is called a fistula. A fistula is an abnormal connection between organs in the digestive tract, usually between one part of the intestine and another. A fistula can be created after inflammation becomes severe.
The section of the small intestine called the ileum is especially prone to damage from Crohn's disease. The ileum is located in the right lower abdomen. However, ulcers and inflammation can occur in all areas of the digestive tract, from the mouth to the rectum.
A few other parts of the body, such as the eyes and joints, also can be affected by Crohn's disease.
Some people with Crohn's disease have only occasional cramps, or diarrhea. Their symptoms are so mild they do not seek medical attention.
However, most people with Crohn's disease have more bothersome symptoms. They may experience long stretches of time with no symptoms. But these are interrupted by flare-ups of symptoms.
When Crohn's disease first begins, or during a flare-up, you might experience:
Abdominal pain, usually at or below the navel. It is typically worse after meals.
Diarrhea that may contain blood
Sores around the anus
Drainage of pus or mucus from the anus or anal area
Pain when you have a bowel movement
Loss of appetite
Joint pains or back pain
Pain or vision changes in one or both eyes
Weight loss despite eating a normal-calorie diet
Weakness or fatigue
Stunted growth and delayed puberty in children
There is no definitive diagnostic test for Crohn's disease. If you have Crohn's disease, your symptoms and the results of various tests will fit a pattern over time. This pattern will be best explained by Crohn's disease.
It may require months for your doctor to diagnose Crohn's disease with certainty.
Your doctor will look for evidence of intestinal inflammation. He or she will try to distinguish it from other causes of intestinal problems such as infection or ulcerative colitis. Ulcerative colitis is another disease that, like Crohn's diseases, also causes intestinal inflammation.
Test abnormalities that are often, but not always, found in people with Crohn's disease include:
Blood tests. Show a high white blood cell count or other signs of inflammation. Crohn's disease can interfere with the absorption of vitamin B12, which can lead to anemia, a reduced number of red blood cells: anemia and low levels of vitamin B12 can show up on blood tests.
Autoantibody tests. Reveal antibodies in the blood of people with Crohn's disease. They may help distinguish between inflammation caused by Crohn's disease versus ulcerative colitis.
Stool tests. Also called feces or bowel movement tests.
Detect small amounts of blood from irritated intestines.
Make sure that there is no infection causing the symptoms.
Upper gastrointestinal (GI) series. A test in which x-ray pictures are taken of your abdomen after you drink a barium solution that shows up on X-rays. As the liquid trickles down, it traces the outline of your intestines on the X-ray. An upper GI series can reveal places in the small intestine that are narrowed. It also can highlight ulcers and fistulas. These abnormalities are found more often in Crohn's disease than in ulcerative colitis, or other conditions that cause symptoms similar to Crohn's disease symptom.
Flexible sigmoidoscopy or colonoscopy tests. These tests use a small tube with an attached camera and light. The tube is inserted into your rectum, allowing your doctor to view the insides of your large intestine. These tests are usually done when Crohn's disease is suspected.
MR Enterography. A relatively new test that provides pictures of the entire intestine without radiation. It uses magnetic resonance imaging to show areas of Crohn's involvement.
Wireless capsule endoscopy. The test involves swallowing a pill-sized object that is a tiny little video camera. It sends pictures of your small intestine wirelessly. Unlike x-ray studies such as the upper GI series, no x-ray radiation is involved.
Biopsy. The removal of a small sample of tissue from the lining of the intestine. The material is examined in a laboratory for signs of inflammation. A biopsy is most helpful to confirm Crohn's disease and to exclude other conditions.
Crohn's disease is a lifelong condition. But it is not continuously active.
Following a flare-up, symptoms can stay with you for weeks or months. Often these flare-ups are separated by months or years of good health without any symptoms.
There is no way to prevent Crohn's disease.
But you can keep the condition from taking a heavy toll on your body. Maintain a well-balanced, nutritious diet to store up vitamins and nutrients between episodes or flare-ups. By doing so, you can decrease complications from poor nutrition, such as weight loss or anemia.
Also, do not smoke. Along with many other harmful health effects, smoking probably makes flare-ups of Crohn's disease happen more frequently.
Crohn's disease can increase your risk of getting colon cancer. Have your colon checked regularly for early cancerous or precancerous changes. If you have had Crohn's disease affecting the colon or rectum for eight years or more, start getting regular colonoscopies. Have a colonoscopy exam every one to two years once you start regular testing.
Medications are very effective at improving the symptoms of Crohn's disease. Most of the drugs work by preventing inflammation in the intestines.
A group of anti-inflammatory drugs called aminosalicylates are usually tried first. Aminosalicylates are chemically related to aspirin. They suppress inflammation in the intestine and joints. They are given either as pills by mouth or by rectum, as an enema.
Certain antibiotics help by killing bacteria in irritated areas of the bowel. They may also decrease inflammation.
Antidiarrheal medications such as loperamide (Imodium) may be helpful if you have diarrhea.
Other more powerful anti-inflammatory drugs may be helpful. But they can also suppress your immune system, increasing your risk of infections. For this reason, they are not often used on a long-term basis.
The newest drugs approved for treatment of Crohn's disease are tumor necrosis factor (TNF) inhibitors. These medications block the effect of TNF. TNF is a substance made by immune system cells that causes inflammation. TNF inhibitors have potentially very serious side effects. They are generally prescribed for moderate to severe Crohn's disease that is not responding to other therapies. Infliximab (Remicade), adalimumab (Humira) and Certolizumab pegol (Cimzia) are TNF inhibitors.
Surgery to remove a section of the bowel is another possible treatment. In general, surgery is recommended only if a person has:
Persistent symptoms despite medical therapy
A non-healing fistula
When To Call A Professional
New or changing symptoms often mean that additional treatment is needed. People who have Crohn's disease should be in frequent contact with a doctor.
One serious complication is bowel obstruction. This occurs when the intestine becomes so narrowed that the digestive contents cannot pass through. Bowel obstruction causes vomiting or severe abdominal pain. It requires emergency treatment.
Other symptoms that require a doctor's immediate attention are:
Fever, which could indicate infection
Heavy bleeding from the rectum
Black, paste-like stools
Crohn's disease can affect people very differently. Many people have only mild symptoms. They do not require continuous treatment with medication.
Others require multiple medications and develop complications. Crohn's disease improves with treatment. It is not a fatal illness, but it cannot be cured.
Crohn's requires people to pay special attention to their health needs and to seek frequent medical care. But it does not prevent most people from having normal jobs and productive family lives.
It can be helpful for a newly diagnosed person to seek advice from a support group of other people with the disease.
Learn more about Crohn's Disease
Symptoms and treatments
Mayo Clinic Reference
Crohn's and Colitis Foundation of America
386 Park Ave. South
New York, NY 10016
Phone: (212) 685-3440
Toll-free: (800) 932-2423
Fax: (212) 779-4098
National Institute of Diabetes and Digestive and Kidney Disorders
31 Center Dr.
Bethesda, MD 20892
Phone: (301) 496-3583
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.