Crohn’s disease is an inflammation of the gastrointestinal (GI) tract. It affects the deepest layers of the intestinal walls. The development of ulcers, or open sores, in the GI tract is a main symptom of Crohn’s.

According to the Crohn’s and Colitis Foundation of America, up to 700,000 Americans have Crohn’s disease. Anyone can have Crohn’s disease, but it’s most likely to affect people between the ages of 15 and 35.

Ulcers that occur with Crohn’s disease can appear from the mouth to the anus, including the:

  • esophagus
  • duodenum
  • appendix
  • stomach
  • small intestine
  • colon

Crohn’s disease rarely affects the:

  • mouth
  • stomach
  • duodenum
  • esophagus

A similar condition is ulcerative colitis, which affects only the colon.

For example, you may have ulcers throughout the colon if you have Crohn’s. You may also have a string of ulcers in only one part of the colon. In other parts of the GI tract, ulcers may exist in clusters separated by intact, healthy tissue. Chronic inflammation can also lead to ulcers in the genital area or the anus.

Oral ulcers

Aphthous ulcers

Occasionally, people with Crohn’s will develop painful sores in the mouth. These are known as aphthous ulcers. These oral ulcers usually appear during a flare-up of intestinal inflammation. They can resemble the common canker sore. Occasionally, much larger ulcers may appear.

Pyostomatitis vegetans

Pyostomatitis vegetans is rare. It causes multiple abscesses, pustules, and ulcers in the mouth. It can occur with inflammatory bowel disease (IBD) or Crohn’s disease. You can take oral and topical corticosteroids, as well as what are called “immune-modulating” drugs, to treat these sores.

Oral ulcers due to medication side effects

Sometimes, oral ulcers may be a side effect of medications that treat Crohn’s and IBD. These medications can cause thrush, an oral fungal infection.

Ulcers from Crohn’s can have several symptoms:


An ulcer can create a fistula if it breaks through your intestinal wall. A fistula is an abnormal connection between different parts of the intestine, or between the intestine and the skin or another organ, such as the bladder. An internal fistula may cause food to bypass areas of the bowel completely. This can lead to inadequate absorption of nutrients. External fistulas may cause the bowel to drain onto the skin. This can cause a life-threatening abscess if you don’t get treatment for it. The most common type of fistula in people with Crohn’s occurs in the anal area.


Visible bleeding is rare, but it may occur if an ulcer tunnels into a large blood vessel or artery. The body usually acts quickly to seal off the bleeding vessel. For many people, this occurs only once. However, surgery may be necessary if bleeding happens often.

Rarely, a person with Crohn’s disease will experience sudden, massive bleeding. The bleeding may occur at any time, including during a flare-up or while the disease is in remission. A massive hemorrhage usually requires lifesaving surgery to remove the diseased segment of the colon or GI tract or to prevent another life-threatening hemorrhage in the future.


Even when there’s no visible bleeding, Crohn’s can lead to iron deficiency anemia if it causes multiple ulcers in the small intestine or colon. Continuous, low-grade, chronic blood loss from these ulcers can occur. If you have Crohn’s that affects the ileum or if you’ve had surgery to remove part of your small intestine called the ileum, you may develop anemia due to an inability to absorb enough vitamin B-12.


Your body’s immune response can cause inflammation. Immunosuppressants are drugs that suppress the immune response.

Corticosteroids are drugs that suppress the immune system to reduce the occurrence of inflammation and ulcers. You can take them orally or rectally. However, the Crohn’s and Colitis Foundation of America reports that they can have side effects and doctors tend not to prescribe them for the long term, if possible. It’s likely your doctor will add a second line of drugs that suppress your immune system.

If you have Crohn’s that hasn’t responded to corticosteroids or is in remission, your doctor may prescribe another type of immunosuppressant such as azathioprine or methotrexate. It usually takes three to six months for a response from these drugs to occur. These drugs may increase your risk of cancer and viral infections such as herpes and cytomegalovirus. You should discuss your risks with your doctor.

Other treatments

Additional treatments for Crohn’s include the following:

  • In the case of mouth ulcers, a topical anesthetic such as lidocaine may help numb the pain. If you receive a topical anesthetic, it’s likely that it will be mixed with a topical corticosteroid.
  • Biologic therapies such as infliximab and adalimumab are other possible treatments for Crohn’s.
  • Your doctor may also prescribe antibiotics that help reduce the number of bacteria in the intestines and reduce inflammation.


Your doctor may recommend surgery to remove a part of the bowel that has a lot of ulcers. Your doctor can’t cure Crohn’s with surgery, but surgery may help alleviate symptoms. An ileum resection is a procedure in which your doctor removes a part of your small intestine called the ileum. If you’ve had an ileum resection or you have severe Crohn’s of the ileum, you’ll need to take vitamin B-12.

Crohn’s disease is a chronic condition. No cure is available, but many people can successfully manage their symptoms. Ulcers are a particularly painful symptom of the disease. You can reduce how frequently they occur and how long they last with medical treatment and lifestyle management. Ask your doctor about lifestyle changes and medical treatments that may work for your condition.