Doctors call mouth ulcers and other symptoms outside of the digestive tract extra-intestinal manifestations of Crohn's disease.

Some people develop mouth ulcers several years before they experience any intestinal symptoms due to Crohn's disease.

Researchers estimate that 20 to 50 percent of people with Crohn's disease experience mouth ulcers at some point.

In this article, learn more about the symptoms, causes, and treatments available for Crohn's mouth ulcers.

Symptoms

Crohn's disease commonly causes mouth ulcers known as canker sores. These develop around the base of the gums.

They differ from other mouth lesions, such as herpes, which appear on the outside of the mouth on the lips.

The ulcers may have the following characteristics:

• round or oval shape
• small size
• yellow or gray color
• a red "halo" or border
• painful
• appearing in groups

Many people with Crohn's disease will notice their mouth ulcers get worse during a flare-up. They may even observe mouth ulcers before other flare-up symptoms begin.

In rare cases, Crohn's disease may also cause pustules, or fluid-filled ulcers, called pyostomatitis vegetans to develop in the mouth.

Causes

Crohn's mouth ulcers may occur for several different reasons, including:

• inflammation in the body linked to Crohn's disease
• vitamin and mineral deficiencies
• as side effects of Crohn's disease medications

As a result, Crohn's may either directly or indirectly lead to mouth ulcers. Men and children with the condition are more likely to have mouth ulcers.

People with Crohn's disease are more likely to develop mouth ulcers than people with other inflammatory bowel conditions, such as colitis.

Having Crohn's disease also puts a person at risk for some nutritional deficiencies, which may contribute to mouth problems. For example, vitamin B-12 and zinc deficiencies can both cause glossitis. A vitamin K deficiency can cause bleeding gums.

Sometimes mouth ulcers can develop as a side effect of Crohn's medications.

A doctor should discuss the potential side effects of Crohn's medications before prescribing them.

Medications and their possible side effects include:

• Budenoside, a steroid that can cause tongue redness and swelling.
• Ciclosporin, which can cause gum swelling.
• Loperamide, an antidiarrhea medication that can cause dry mouth.
• Methotrexate, a folic acid antagonist that can cause ulcers and gingivitis.
• Tacrolimus, which can cause mouth ulcers and oral thrush.

Anyone who experiences these symptoms should continue to take their medications, and talk to their doctor about switching medicines or treating the side effects.