What should you know about red circular rash?

Ringworm may create a scaly ring, but contact dermatitis can follow a product, adhesive, plant, or metal. Atopic dermatitis often affects dry, sensitive skin; psoriasis may form thicker defined plaques; and heat rash tends to appear where sweat and friction occur. Intertrigo affects skin folds, while scabies can cause an intensely itchy rash with lesions in characteristic areas. A drug rash may begin after a new medicine and can spread beyond the original site. The pattern must be interpreted with the history.

Photograph the rash in good light and write down when it started, where it began, and whether it is spreading. List recent medicines, skincare products, travel, animals, sweating, and contact with someone itchy. Use gentle cleansing, avoid friction, and do not apply leftover prescription medicine or several active creams together. A clinician can decide whether examination alone is enough or whether testing is useful.

Seek urgent help for a rash with breathing trouble, swelling of the lips or tongue, faintness, skin peeling, widespread blisters, or involvement of the eyes or mouth. Get prompt assessment for fever, severe pain, rapidly spreading warmth, pus, or a rash that follows a new medicine. Persistent, recurrent, or changing lesions also merit a routine review.

Ask what features distinguish infection from inflammation, whether a medicine or exposure is relevant, whether household members need advice, which treatments are safe for the body site, and when to return if the rash changes.