Crohn's disease

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What is Crohn's disease? A Mayo Clinic expert explains

Learn more about Crohn's disease from gastroenterologist William FaubionM.D.

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William A. FaubionJr.M.D.GastroenterologyMayo Clinic: I'm Dr. Bill Faubiona gastroenterologist at Mayo Clinic. In this videowe'll cover the basics of Crohn's disease. What it is? Who gets it? The symptomsdiagnosis and treatment. Whether you're looking for answers for yourself or someone you lovewe're here to give you the best information available. Crohn's disease is an inflammatory bowel disease that causes chronic inflammation of the GI tractwhich extends from your stomach all the way down to your anus. Different areas of the GI tract can be affected in different peopleand it often spreads into the deeper layers of the bowel. It's estimated that over half a million Americans are living with Crohn's disease. It can be painful and debilitatingoccasionally leading to severe complicationsas well as emotionally stressful. And while there is no cureonce you've been diagnosedtreatment can help you get back to a more normal and comfortable life.

Who gets it?

There are a lot of particulars that figure into or aggravate Crohn's diseasebut the exact cause is still unknown. It may involve an abnormal immune response against some microorganism in which your tissues are also attacked. Genetics might also play a role. And it's true that you're at higher risk if a first-degree relative has it. But that's really only seen in about 20% of cases. There is a correlation with age. Although it can show up at any stage of lifemost people are diagnosed before 30. Ethnicity is a risk factor. Whites have the highest riskespecially among people of Ashkenazi Jewish descent. Howeverincidence is increasing among black people in North America and the UK. Non-steroidal anti-inflammatory medications or NSAIDS... they don't cause Crohn's diseasebut they are known to trigger inflammation of the bowel and make it worse. They include common over-the-counter painkillers like ibuprofennaproxen sodiumdiclofenac sodiumand others. So if you've been diagnosed with Crohn'smake sure you talk to your doctor about what medications should be avoided. Many of these elements are out of our handsbut smoking is the most important controllable risk factor for developing Crohn's disease. It also leads to more severe disease and increased need for surgery. So if you smoke and you're diagnosednow is a good time to quit.

What are the symptoms?

Crohn's disease can affect any area in the GI tractbut it's mostly found in the large and the small intestine. It can also be confined to one area or found in multiple segments. Symptoms can range in severity and it can depend on the area of the GI tract that's affected. You also may experience periods of remission when you have no symptoms or issues at all. The symptoms can come on graduallybut they can also show up suddenly. And these can include diarrheafeverfatigueabdominal pain and crampingblood in your stoolmouth soresreduced appetite and weight loss. If your Crohn's disease has caused fistulas or inflamed tunnels in the skin near the anal areayou may notice pain or drainage. And in more severe casesyou may have inflammation of the eyesskinjointsliver or bile ductskidney stonesand anemia. In childrenit can delay growth and development. Over timeCrohn's disease can lead to other complicationsincluding bowel obstructionulcersfistulasanal fissuresmalnutritionand other health problems. It can also increase your risk for blood clots and colon cancer. Having these symptoms doesn't automatically mean you have Crohn's. But if you're experiencing anything that concerns youit's a good idea to make an appointment with your doctor.

How is it diagnosed?

There's no single test for Crohn's diseaseand it has similar symptoms to a lot of other conditionsso it can take a little time to get a diagnosis. Firstyour doctor is going to consider your medical history. Then your doctor may want to run a variety of tests or procedures. And at some pointyour general practitioner may want to refer you to a specialist called a gastroenterologist like myself. A blood test can check for anemia and check for signs of infection. A stool study can test if there's blood present or rule out certain pathogens. A colonoscopy may be needed. This also allows your doctor to view your entire colon and the very end of the ileum using an endoscopea small camera mounted on a thin flexible tube. They can take tissue samples for a biopsy at the same time. And the presence of granulomas or clusters of inflammatory cellscan essentially confirm the diagnosis. A CT scan might be ordered for a better look at the bowel and all of the surrounding tissues; or an MRIwhich is especially good for evaluating fistulas around the anus or the small intestine. A capsule endoscopy can be done. Here you actually swallow the camera about the size of a large vitamin and it takes images of your digestive tract as it travels through. And a balloon-assisted enteroscopy may be done to get further into the bowel than a standard endoscope can if abnormalities have been found that need further investigation.

How is it treated?

Your doctor can work with you to find therapies that alleviate your symptoms. One of the main goals is to reduce the inflammation that produces painful and disruptive issues. Another is to limit complications over the long-term. There is currently no curebut many treatments can provide a lot of reliefand in some caseseven long-term remission. These may include anti-inflammatory drugs like corticosteroidsimmune system suppressantsand antibiotics. Certain biologicswhich target proteins made by the immune systemcan help. Antidiarrhealspain relieversand supplements can help counter other symptoms. Nutritional therapy and a special diet may be recommended. And in some cases where other measures aren't effectivesurgery may be required. And that's to remove the damaged tissue. Some of these therapies may have side effects themselves. So be sure and review the risks and benefits with your doctor.

What now?

Crohn's disease can be physically and emotionally challengingbut there are things that can help. Although there's no firm evidence that any particular foods cause Crohn's diseasecertain things seem to aggravate flare-ups. So a food diary can help you identify personal triggers. Beyond thatlimit dairy productseating smaller mealsstay hydratedand try to avoid caffeinealcoholand carbonation. Consider multivitamins if you're concerned about weight loss. Or if your diet has become too limitedtalk to a registered dietitian. And againif you smokeyou should stop. It's important to take care of your mental health too. Find ways to manage stresslike exercisebreathingrelaxation techniques or biofeedback. Some symptoms like abdominal paingasand diarrhea... they can cause anxiety and frustration. They can make it difficult to go out in public for any amount of time. It can feel limiting and isolating and lead to depression. So learn as much as you can about Crohn's. Staying informed can help a lot in feeling like you're in control of your condition. Talk to a therapistespecially one familiar with inflammatory bowel disease. Your doctor can give you some recommendations. And you might want to find a support group of people going through the same thing that you are. Crohn's disease is a complex disease. But having expert medical care and developing a treatment strategy can make it more manageable and even help you get back to the freedom of your normal life. Meanwhilesignificant advances continue to be made in understanding and treating the diseasegetting us closer to curing it or preventing it entirely. If you'd like to learn more about Crohn's diseasehere are other related videos or visit mayoclinic.org. We wish you well.

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Crohn's disease is a type of inflammatory bowel disease (IBD) that causes swelling and irritation of the tissuescalled inflammationin the digestive tract. This can lead to belly painsevere diarrheafatigueweight loss and malnutrition.

Inflammation caused by Crohn's disease can affect different areas of the digestive tract in different people. Crohn's most commonly affects the end of the small intestine and the beginning of the large intestine. The inflammation often spreads into the deeper layers of the bowel.

Crohn's disease can be both painful and debilitating. Sometimesit may lead to serious or life-threatening complications.

There's no known cure for Crohn's diseasebut therapies can greatly reduce its symptoms and even bring about long-term remission and healing of inflammation. With treatmentmany people with Crohn's disease can function well.

Symptoms

Symptoms of Crohn's disease typically include:

  • Diarrhea.
  • Fever.
  • Fatigue.
  • Belly pain and cramping.
  • Blood in the stool.
  • Mouth sores.
  • Reduced appetite and weight loss.
  • Pain or drainage near or around the anus due to inflammation from a tunnel into the skincalled a fistula.

Crohn's disease can affect any part of the small or large intestine. It may involve multiple segmentsor it may be continuous. It most commonly involves the last part of the small intestine. In some peoplethe disease is only in the colon or the large intestine.

Symptoms of Crohn's disease can range from mild to severe. They usually develop graduallybut sometimes might come on suddenlywithout warning. Someone with Crohn's disease also may have periods of time with no symptoms. This is known as remission.

Other symptoms

People with severe Crohn's disease also may experience symptoms outside of the intestinal tractincluding:

  • Inflammation of skineyes and joints.
  • Inflammation of the liver or bile ducts.
  • Kidney stones.
  • Iron deficiencycalled anemia.
  • Delayed growth or sexual developmentin children.

When to see a doctor

See a healthcare professional if you have ongoing changes in your bowel habits or if you have any symptoms of Crohn's diseasesuch as:

  • Belly pain.
  • Blood in the stool.
  • Nausea and vomiting.
  • Diarrhea lasting more than two weeks.
  • Losing weight without trying.
  • Fever in addition to any of the above symptoms.
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Causes

The exact cause of Crohn's disease remains unknown. Previouslydiet and stress were suspectedbut now healthcare professionals know that these factors may aggravatebut don't causeCrohn's disease. Several factors likely play a role in its development.

  • Genes. More than 200 genes have been associated with Crohn's disease. Howeverresearchers aren't exactly sure what role they play in the condition. Having one or more of these genes may make someone more likely to get Crohn's disease.
  • Immune system. It's possible that bacteriaviruses or other environmental factors may trigger Crohn's disease. For examplecertain bacteria in the gut microbiome are suspected to be associated with Crohn's diseasebut it is unknown if these bacteria cause Crohn's disease. When the immune system tries to fight off an invading microorganism or environmental triggersan atypical immune response causes the immune system to attack the cells in the digestive tracttoo.

Risk factors

Risk factors for Crohn's disease may include:

  • Family history. People with a first-degree relativesuch as a parentsibling or childare at higher risk to have the disease. As many as 1 in 5 people with Crohn's disease has a family member with the disease.
  • Age. Crohn's disease can happen at any agebut it's more common to develop the condition when you're young. Most people who develop Crohn's disease are diagnosed before they're around 30 years old.
  • Ethnicity. Although Crohn's disease can affect any ethnic groupwhite people have the highest riskespecially people of Eastern European (Ashkenazi) Jewish descent. Howeverthe incidence of Crohn's disease is increasing among Black people who live in North America and the United Kingdom. Crohn's disease also is being increasingly seen in the Middle Eastern population and among migrants to the United States.
  • Cigarette smoking. Cigarette smoking is the most important controllable risk factor for developing Crohn's disease. Smoking also leads to more-serious disease and a greater risk of having surgery. If you smokeit's important to stop.
  • Nonsteroidal anti-inflammatory medicines. These include ibuprofen (AdvilMotrin IBothers)naproxen sodium (Aleve)diclofenac sodium and others. While they do not cause Crohn's diseasethey can lead to inflammation of the bowel that makes Crohn's disease worse.

Complications

Crohn's disease may lead to one or more of the following complications:

  • Bowel blockage or obstruction. Crohn's disease can affect the entire thickness of the intestinal wall. Over timeparts of the bowel can scar and narrowwhich may block the flow of digestive contentsoften known as a stricture. Surgery to widen the stricture or to remove the diseased portion of the bowel may be necessary.
  • Ulcers. Ongoing inflammation can lead to open sores called ulcers anywhere in the digestive tract. This can include the mouthanus and genital area.

  • Fistulas. Sometimes ulcers can extend completely through the intestinal wallcreating a connection between different body parts that shouldn't be there. This is known as a fistula. Fistulas can develop between the intestine and the skinor between the intestine and another organ. Fistulas near or around the anal area are the most common kind.

    When fistulas develop inside the abdomenit may lead to infections and collections of pus called abscesses. This can be life-threatening if not treated. Fistulas may form between loops of bowelin the bladder or vaginaor through the skincausing continuous drainage of bowel contents to the skin.

  • Anal fissure. This is a small tear in the tissue that lines the anus or in the skin around the anus where infections can occur. It's often associated with painful stool and may lead to a fistula.
  • Malnutrition. Diarrheabelly pain and cramping may make it difficult to eat or for the intestine to absorb enough nutrients. It's also common to develop anemia due to low iron or vitamin B-12 caused by the disease.

  • Colon cancer. Having Crohn's disease that affects the colon increases the risk of colon cancer. General colon cancer screening guidelines for people without Crohn's disease call for a colonoscopy at least every 10 years beginning at age 45.

    In people with Crohn's disease affecting a large part of the colona colonoscopy to screen for colon cancer is recommended about eight years after disease onset and generally is performed every 1 to 2 years afterward. Ask a healthcare professional whether you need to have this test done sooner and more frequently.

  • Skin disorders. Many people with Crohn's disease also may develop a condition called hidradenitis suppurativa. This skin disorder involves deep nodulestunnels and abscesses in the armpitsgroinunder the breastsand in the perianal or genital area. Some Crohn's disease treatments also increase the risk of skin cancersso a routine skin examination is recommended.
  • Other health problems. Crohn's disease also can cause problems in other parts of the body. Among these problems are low ironcalled anemiaosteoporosisarthritiskidney stoneseye problemsand gallbladder or liver disease.

  • Medicine risks. Certain Crohn's disease medicines that block functions of the immune system are associated with a small risk of developing cancersincluding lymphoma and skin cancers. They also increase the risk of infections.

    Corticosteroids can be associated with a risk of osteoporosisbone fracturescataractsglaucomadiabetes and high blood pressureamong other conditions. Work with a healthcare professional to determine risks and benefits of medicines.

  • Blood clots. Crohn's disease increases the risk of blood clots in veins and arteries.

By Mayo Clinic Staff

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Dec. 042025
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