Crohn's disease and canker sores: what to know

A canker sore is a shallow, painful ulcer inside the mouth, often on the inner lip, cheek, tongue, or gums. People with Crohn's disease may develop mouth ulcers during active inflammation, although a sore can also have unrelated causes such as irritation from a sharp tooth or biting the cheek.

Poor intake during a flare can make it harder to obtain nutrients needed for healthy mouth tissue. Some medicines can also cause mouth changes or lower the body's ability to fight infection. The sore itself does not prove that Crohn's disease is active, so its timing and other symptoms matter.

Choose cool, soft foods while the area is tender and avoid spicy, acidic, or rough-textured foods that sting. Use a soft toothbrush and rinse gently with plain water after meals. Do not pick at the ulcer or apply household chemicals to it.

Keep a note of when sores appear, how long they last, and whether they occur with abdominal pain or diarrhoea. A GP consultation can help review medicines, nutrition, and other possible causes. A blood test may be considered when deficiency or inflammation needs checking.

Arrange medical advice if sores keep returning, make eating or drinking difficult, or do not start improving. Seek urgent help for swelling that affects breathing or swallowing, severe dehydration, or severe abdominal symptoms with a mouth flare.

Could my mouth ulcers be related to Crohn's inflammation, a nutrient problem, or a medicine? What signs would show that my bowel disease needs review? Should my mouth be examined or should I have a blood test?