Heat rash white spots: what to know

With heat rash, small pale or translucent spots can occur where sweat has collected beneath the outer skin. The surrounding area may feel prickly or itchy after heat, exercise or prolonged covering. If the marks are flat, sharply outlined, scaly, painful, or present without a heat trigger, another skin condition may be involved. Compare the area with nearby skin in good light, but avoid relying on colour alone. A [Skin Rash](/symptoms/skin-rash/) page can help you describe the change without treating a visual impression as a diagnosis.

Cool the body, reduce sweating and keep the area uncovered when practical. Choose loose fabric, rinse away sweat with lukewarm water, and dry by patting. Avoid scratching, exfoliating acids, fragranced sprays and thick greasy layers over the spots. A simple, light moisturiser may reduce dryness once the skin is cool; see [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) for context. Do not use a steroid product on an uncertain rash without professional advice. A clinician may consider [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) when inflammation has been assessed.

Contact a clinician if the spots persist after the heat and sweat have settled, spread, become scaly or painful, or recur without an obvious trigger. Seek prompt care for fever, pus, rapidly increasing redness, significant swelling, breathing difficulty or feeling faint. Infants, people with extensive skin involvement, and anyone with a weakened immune system may need earlier advice.

Ask whether the marks are consistent with [Heat Rash](/conditions/heat-rash/), whether a lightening or pigment condition should be considered, and which cleanser or moisturiser is suitable. Tell the clinician about recent heat exposure, new products, medicines, itch, scale, pain and how the spots change when the skin cools.