What Causes Heat Rash?

When the body sweats heavily, immature or irritated sweat ducts may not release perspiration normally. Sweat then leaks into nearby skin, producing small red or skin-coloured bumps, prickling, itching, or a stinging sensation. The rash often appears in folds, under clothing, on the neck, chest, back, or areas covered by nappies. Babies can develop it because their sweat ducts are still developing, while adults may notice it after exercise, fever, bed rest, or spending time in a warm environment. A tendency to sweat heavily can add to the problem.

Move to a cooler place and let the skin dry. Wear loose, breathable clothing and change out of damp garments. A cool shower or a clean, cool compress can reduce prickling; pat rather than rub afterward. Avoid thick ointments, fragranced products, and vigorous scrubbing because they can block ducts or irritate already inflamed skin. Keep skin folds as dry as practical. If the rash does not improve after cooling and gentle care, a clinician can check whether another condition is responsible.

Arrange medical advice if the rash is spreading, very painful, repeatedly returning, or not settling after the heat and sweating have stopped. Seek prompt care for fever, pus, increasing warmth, marked swelling, or feeling unwell, as these can point to infection or a different skin problem. Trouble breathing, faintness, or confusion during overheating requires urgent help.

Could this be heat rash or a condition such as folliculitis or contact dermatitis? What products should I avoid on the affected area? How can I prevent it during exercise, travel, or hot weather?