Ringworm on the bum: what to know

Ringworm is a fungal infection of the outer skin. On the bum, it may look like a dry patch with an advancing border, mild central clearing, or uneven scale. A skin rash is a common presentation of ringworm, but sweat, rubbing, eczema, psoriasis, bacterial infection, and irritation from wipes or cleansers can mimic it. The words bum and bottom can describe different areas, so tell the clinician whether the rash is on the cheek, crease, anus, or nearby groin.

A clinician may inspect the feet, nails, and groin for another fungal site. Testing scale can help when the shape is atypical, the skin is very inflamed, or symptoms return after treatment.

Wash gently, dry carefully, wear loose clothing, and change after sweating. Keep towels and clothing separate until the cause is clear, and launder items that touch the area. If ringworm is confirmed, follow the prescribed [Topical Antifungal Treatment](/treatments/medical-dermatology/topical-antifungal-therapy/) directions. A clinician may choose [Oral Antifungal Treatment](/treatments/medical-dermatology/oral-antifungal-therapy/) when the infection is extensive, recurrent, or difficult to treat on the skin.

Seek prompt medical attention for fever, rapidly spreading redness, increasing warmth, pus, severe pain, or a painful swelling. Get an examination for bleeding, ulcers, discharge, anal pain, or a new rash after sexual contact. If an antifungal has not helped as expected, stop guessing at the cause and arrange a review; the correct treatment depends on the diagnosis.

Ask whether the rash is in a location typical for ringworm, whether testing is needed, and how long treatment should continue. Mention new soaps or wipes, exercise and sweating, close contacts with rashes, foot symptoms, allergies, and every cream or home remedy applied.