Heat Rash Causes and Prevention

Sweat normally reaches the skin surface and evaporates. Heat, humidity, tight clothing, occlusive products and skin-to-skin contact can interfere with that process. Trapped sweat irritates the surrounding skin, producing prickling, small bumps or a red rash. Babies, people who sweat heavily and anyone spending time in hot environments may notice it more readily. See [Heat Rash](/conditions/heat-rash/) for the condition overview.

Choose loose, breathable clothing and change out of damp garments promptly. Take breaks in shade or air conditioning, keep folds dry, and use cool water after heavy sweating. Limit thick creams or oily products on areas that overheat unless a clinician has recommended them. Notice your triggers: exercise, outdoor heat, bedding or protective equipment can each create warmth and friction. Related [Skin Bumps](/symptoms/skin-bumps/) and [Skin Rash](/symptoms/skin-rash/) pages can help you describe what you see.

Contact a clinician when episodes recur despite cooling measures, last after the trigger has gone, or become painful, swollen, crusted or filled with fluid. Fever or a child who seems unwell warrants prompt advice. A different cause may need consideration when the pattern is unusual; [Skin Redness](/symptoms/skin-redness/) is a useful symptom reference.

Ask which trigger is most likely, whether a product or medicine is worsening blockage, and how to protect a frequently affected skin fold. Ask before using [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) or [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) on a recurrent rash.