What should you know about a ring-shaped rash?

Ringworm often expands outward and may have a more active, scaly edge with clearer skin toward the centre. Atopic dermatitis or contact dermatitis can form irregular patches and may follow dryness or exposure to a product. Psoriasis can produce thicker, sharply defined scaling. Scabies is more often intensely itchy, especially at night, and may affect close contacts. A photograph and examination can be more useful than the shape alone.

Keep the area clean and dry, avoid scratching, and do not share towels, clothing, or sports equipment while an infection remains possible. Avoid using a steroid cream alone on a scaly expanding ring unless a clinician has advised it, because it can alter the appearance of a fungal rash. A clinician may recommend an antifungal or a different treatment after examining the skin.

Arrange an assessment if the rash is spreading, recurring, painful, oozing, or not improving with sensible skin care. Seek urgent help for facial swelling, breathing trouble, fever with a rapidly worsening rash, extensive blistering, or involvement of the eyes or mouth.

Ask whether the edge suggests a fungal infection, whether testing is needed, how long treatment should continue, and which household items or contacts should be checked.