Crohn’s Disease

Written by WebMD Editorial Contributors
Medically Reviewed by Murtaza Cassoobhoy, MD on April 13, 2023

Crohn’s disease causes inflammation in part of your digestive system. Crohn's can affect any part of it, but it most often involves your small intestine and colon.

Crohn's and another disease, ulcerative colitis, are part of a group of conditions called inflammatory bowel disease.

There’s no cure for Crohn’s, but treatment can ease your symptoms and help you enjoy a full, active life.

People with Crohn's disease can have severe symptoms, followed by periods of no symptoms that may last for weeks or years. The symptoms depend on where the disease happens and how severe it is. You might notice:

 

Crohn’s causes two types of complications:

  • Local, which affect just your intestines
  • Systemic, which affect your whole body. You might hear them called extraintestinal complications.

Local complications of Crohn’s include:

  • Abscess. This pocket of pus happens because of bacterial infections. It can form on the walls of your intestines and bulge out. Or you might get one near your anus that looks like a boil. You’d notice swelling, tenderness, pain, and fever.
  • Bile salt diarrhea. Crohn’s disease most often affects the ileum, the lower end of your intestine. This part usually absorbs bile acids, which your body makes to help it absorb fat. If your body can’t process the fat, you could get this type of diarrhea.
  • Fissure. This is a painful tear in the lining of the anus. It can cause bleeding during bowel movements.
  • Fistula. Sores or ulcers can turn into openings called fistulas that connect two parts of your intestine. They can also tunnel into nearby tissues, like the bladder, vagina, and skin.
  • Malabsorption and malnutrition. Crohn's affects your small intestine, the part of your body that absorbs nutrients from food. After you’ve had it for a long time, your body may no longer be able to make the most of what you eat.
  • Small intestinal bacterial overgrowth (SIBO). Your gut is full of bacteria that help you break down food. When this happens higher up in your digestive tract than usual, you can get gas, bloating, belly pain, and diarrhea.
  • Strictures. These narrowed, thickened areas of your intestines result from the inflammation that comes with Crohn’s. They can be mild or severe, depending on how much of your intestine is blocked. Symptoms include cramping, abdominal pain, and bloating.

Systemic complications include:

Arthritis. Joint inflammation, which leads to pain, swelling, and a lack of flexibility, is the most common systemic complication. Three types of arthritis sometimes come with Crohn’s:

  • Peripheral. This type affects large joints in your arms and legs, like your elbows, knees, wrists, and ankles.
  • Axial. This type affects your spine or lower back (the doctor may call it your sacroiliac joint).
  • Ankylosing spondylitis. This more serious type of spinal arthritis is rare among people with Crohn’s, but it can happen. It can also lead to inflammation in your eyes, lungs, and heart valves.

Skin problems. These are the second most common systemic complication. Those most often linked to Crohn’s disease include:

  • Erythema nodosum. These small, tender, red nodules usually show up on your shins, ankles, and sometimes arms.
  • Pyoderma gangrenosum. These pus-filled sores often follow an injury or other skin trauma. They often appear on your legs but can show up anywhere.
  • Skin tags. These small flaps of skin are common in people with Crohn’s, especially around the anus.
  • Mouth ulcers. You might hear them called canker sores. They form between your gum and lower lip or along the sides and bottom of your tongue.

Bone loss. Medications like steroids can lead to bone loss, a condition known as osteoporosis. They can:

  • Stop your body from absorbing calcium, which it needs to build bone
  • Make your body get rid of calcium when you pee
  • Boost production of cells that break down bone
  • Lower the number of cells that help form bones
  • Lower your body’s output of estrogen. Estrogen also helps build bone.

The proteins that cause inflammation can also change the speed at which your body removes and makes bone.

Lack of vitamin D. If your body can’t absorb vitamin D because of Crohn’s damage to the small intestine, or if part of your small intestine has been removed, you’re less likely to be able to absorb calcium and make bone.

Eye problems. Inflammation associated with Crohn’s can affect the eyes in several ways. Common conditions include:

  • Episcleritis. Inflammation of the area just below the conjunctiva (the clear tissue that covers the inside of your eyelids and the white of your eye) is the most common complication of Crohn’s. It can affect one eye or both. You’ll notice pain, itching, burning, and severe redness, but it won’t typically hurt your vision.
  • Scleritis. This condition causes constant pain that gets worse when you move your eyes.
  • Uveitis. This is a painful inflammation of the uvea, the middle layer of your eye. It can cause blurry vision, light sensitivity, and redness.

Kidney problems. These organs can be affected by Crohn’s because they play a role in processing waste and are near your intestines. Potential issues include:

  • Kidney stones. They’re a common problem with Crohn’s. One type occurs when a salt called oxalate gets absorbed into your kidneys and turns into stones. Another type, called uric acid stones, forms if your body cannot absorb all the uric acid that it makes.
  • Hydronephrosis. This happens when the ileum (where the small intestine meets the large) swells from Crohn’s and puts pressure on a ureter, the tube that carries urine from your kidney to your bladder. When urine can’t drain as it should, your kidney swells, and scar tissue can form.
  • Fistulas. In addition to forming within your intestines, fistulas can form between the intestine and other organs, like the bladder or ureter.

Liver problems. Your liver processes everything you eat and drink. It can get inflamed as a result of Crohn’s treatment or the disease itself. You’re likely to have only low energy and fatigue unless you get a more serious problem. Among the most common issues are:

  • Fatty liver disease. When your body doesn’t process fats as well, they can build up in your liver. Steroids can help.
  • Gallstones. When Crohn’s affects the ileum, it can’t process bile salts, which help cholesterol dissolve. The cholesterol can form stones that block the opening between your liver and the bile duct.
  • Hepatitis. Long-term liver inflammation can result from Crohn’s disease itself.
  • Pancreatitis. Inflammation of the pancreas can result from both gallstones and medications. It can cause pain, nausea, vomiting, and fever.

Physical development problems. Crohn’s can start at any age. When kids get Crohn’s, parents are likely to notice:

  • Growth failure. Kids who have Crohn’s are likely to be shorter and weigh less than those who don’t. They may stop getting taller before symptoms start.
  • Delayed puberty. Kids with Crohn’s are likely to start puberty later.

Most studies link Crohn’s disease to a very small but real increase in the chance of death. Usually, the causes are not just Crohn’s disease itself, but related complications. They include infections, a perforation or tear in the bowels, and deadly reactions to steroids and other treatments.

Doctors aren’t sure what causes Crohn's disease. Some people think of it as an autoimmune disease. Research suggests that the long-term inflammation may not happen because your immune system attacks your body, but instead because it attacks a harmless virus, bacteria, or food in your gut.

A few things can make you more likely to get Crohn’s disease:

  • Genes. Crohn's disease is often inherited. About 20% of people who have it may have a close relative with either Crohn's or ulcerative colitis. In addition, Ashkenazi Jews have a higher risk for the disease.
  • Age. While Crohn's disease can affect people of all ages, it’s primarily an illness of the young. Most people are diagnosed before age 30, but the disease can happen in people in their 50s, 60s, 70s, or even later in life.
  • Smoking. This is the one risk factor that’s easy to control. Smoking can make Crohn’s more severe and raise the odds that you’ll need surgery.
  • Medications. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, and similar medications don’t cause Crohn’s disease, but they can lead to inflammation of the bowels that makes it worse.
  • The world around you. People who live in urban areas or industrialized countries are more likely to get Crohn’s.
  • Diet. If you eat a lot of high-fat or processed foods, your odds of Crohn’s could go up.
  • Infection. Bacteria linked to Crohn’s include Mycobacterium aviumparatuberculosis, which causes a similar condition in cattle, and a type of E. coli.

 

There are five types of Crohn’s disease, based on what part of your digestive tract is affected.

  • Ileocolitis, the most common form of Crohn’s, involves your colon and the last part of your small intestine (called the terminal ileum).
  • Crohn’s colitis or granulomatous colitis affects only your colon.
  • Gastroduodenal Crohn’s disease is in your stomach and the first part of your small intestine (called the duodenum).
  • Ileitis affects your ileum.
  • Jejunoileitis causes small areas of inflammation in the upper half of your small intestine (called the jejunum).

 

Doctors use many tests to distinguish Crohn's disease from other conditions like ulcerative colitis.

First, your doctor will review your medical history and talk about your symptoms. They might want to order some lab tests, like:

  • Blood tests, including blood counts
  • Stool samples to rule out infections as the cause of diarrhea
  • Imaging tests:
    • MRI. This shows your doctor a clear picture of the inside of your body without using radiation.
    • CT scan. This test uses X-rays to make detailed images of your internal organs.
  • Endoscopy. Your doctor might send you to a specialist called a gastroenterologist to get one of these:
    • Balloon-assisted enteroscopy. This test uses balloons that inflate and deflate to pull a flexible tube called an endoscope through your small intestine. A tiny camera on one end gives a view of the inside of your guts.
    • Capsule endoscopy. You’ll swallow a tiny, pill-sized camera to give the doctor a closer look at your small intestine.
    • Upper endoscopy. The doctor does this to see your esophagus, stomach, and duodenum.
    • Colonoscopy or sigmoidoscopy. These give the doctor a clear picture of your intestines and let them take a tissue sample to study.

 

With Crohn's disease, you have periods of symptoms that can last days, weeks, or months, followed by periods of remission when you have no symptoms. Remissions can last days, weeks, or years.

Things that can worsen Crohn's disease include:

  • Infections (including the common cold)
  • Cigarette smoking
  • Some anti-inflammatory drugs (such as aspirin and ibuprofen)

 

Treatments can’t cure Crohn's disease, but they can help most people lead regular lives.

Medication

Crohn's disease is mostly treated with medications, including:

Biologic medicines will be included in your treatment if you have moderate to severe Crohn’s disease. The anti-TNF drugs are often the first choice and include: 

Other biologics approved for Crohn's include:

Once you start treatment, your doctor will check back in several weeks to see how well it works. You’ll continue until you reach remission. When that happens, your doctor may prescribe "maintenance therapy" to keep your symptoms at bay. If you don’t get better, you’ll need stronger treatment. Your doctor may suggest nutritional supplements, too.

Surgery

About 66% to 75% of people with Crohn's disease will need surgery. It can help with complications or when medications don't work. Common procedures include:

  • Resection. Your surgeon removes the diseased part of the bowel and joins the two healthy ends together. Many people are symptom-free for years after, but it isn’t a cure. Crohn's disease often comes back at the site of the connection, or anastomosis.
  • Ileostomy. You might need this if your rectum is diseased and the doctor can’t use it for an anastomosis. This procedure connects your intestine to the skin of your torso. The result is an opening in the skin that can collect waste products in a special pouch that you empty.

Complementary and alternative treatments

When you use nonmedical treatments instead of medical ones, they’re called alternative therapies. Those used along with medical treatments are called complementary therapies.

Medication is the main treatment for Crohn’s, but many people use complementary therapies to help ease symptoms. They include:

Research on many of these treatments is ongoing. Talk with your doctor before trying any of them.

Lifestyle changes and home remedies

Some lifestyle changes may also relieve your Crohn’s symptoms.

  • Avoid NSAIDs. Use acetaminophen instead.
  • Quit smoking. This may help reduce flare-ups, lessen the amount of medication you need, and lower your chances of surgery.
  • Manage stress. Stress doesn’t cause Crohn’s, but it can make symptoms worse. Try some of the mind-body therapies above, such as meditation or yoga.

Crohn's disease diet

Foods don't seem to cause Crohn's disease, but soft, bland things may cause fewer symptoms than spicy or high-fiber foods when the disease is active. Most doctors try to be flexible in planning the diets of their Crohn's disease patients.

You might also try an elimination diet, which can help you figure out which foods trigger Crohn’s symptoms. You’ll remove things from your diet one at a time to see what happens. Work with your doctor or a dietitian to make sure you don’t miss out on any nutrients while you’re doing it.

See how you feel after cutting back on:

  • Greasy or fried foods
  • Dairy products
  • Carbonated drinks
  • Caffeine
  • High-fiber foods like nuts, seeds, and raw vegetables
  • Foods that can cause gas, such as beans and cruciferous veggies

 

 

Show Sources

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National Digestive Diseases Information Clearinghouse.

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RadiologyInfo.org: “Computed Tomography (CT) -- Body.”

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