Heat rash after sun exposure

The rash may appear beneath tight clothing, along the hairline, on the shoulders, chest or back, or wherever sweat remains against warm skin. Small bumps, prickling and redness are typical features. Sun exposure can also cause sunburn or a light-sensitive reaction, which may look different from heat rash. Skin bumps and skin rash have many possible causes.

Move into shade or an air-conditioned room and cool the area with a damp cloth or a gentle lukewarm rinse. Pat dry rather than rubbing. Choose loose, breathable clothes, pause strenuous activity, and avoid oils, thick ointments and perfumed products while the skin is hot. Once comfortable, a bland moisturiser can help dryness; emollient therapy may be discussed with a pharmacist or clinician. Protect recovering skin from more sun with clothing and shade.

Contact a clinician if redness or bumps continue despite cooling, cover a broad area, recur with sun exposure, or become painful. Get urgent care for confusion, fainting, severe headache, vomiting, breathing difficulty, facial swelling, extensive blistering or signs of infection such as worsening warmth, pus or fever. Do not assume every sun-related rash is heat rash.

Ask how to distinguish heat rash from sunburn, allergy or another light-sensitive eruption, and which sunscreen or skin product is suitable after the rash settles. If itching is persistent, ask whether a topical corticosteroid is appropriate.