Cutaneous Crohn's disease: what to know

Skin findings can include persistent redness, swelling, cracks, ulcers, drainage or painful areas. Lesions near the anus may occur alongside abdominal pain, diarrhoea or other bowel symptoms, but the skin finding itself does not prove that Crohn's disease is the cause. Similar changes can result from infection, irritation, haemorrhoids or another inflammatory condition. A clinician considers the skin examination together with bowel history, medicines and previous diagnoses.

Book a GP consultation or contact your gastroenterology team for a new, persistent or worsening skin change. Gently wash and dry the area, avoid fragranced products and do not scratch or squeeze lesions. Record when the change began, whether it drains or bleeds, and any bowel symptoms. Assessment may include an examination, a blood test or referral to dermatology and gastroenterology. Treatment is tailored to the inflammation, infection or bowel activity identified.

Seek urgent help for rapidly increasing swelling, severe pain, heavy bleeding, pus with fever, inability to pass stool or urine, or feeling faint. Contact your care team promptly if diarrhoea becomes persistent, you cannot maintain fluids, or a wound near the anus is draining and worsening. These signs need assessment for infection, an abscess or active bowel disease.

Ask whether the skin change could be related to Crohn's disease, whether a blood test or swab is useful, how to protect the skin, and whether your bowel treatment needs review.