What causes heat rash?

Heat, humidity, sweating, tight clothing, and skin-to-skin friction can make it harder for sweat to escape. The result may be tiny clear or red bumps, a prickly sensation, itch, or a patchy skin rash. Common sites include the neck, chest, back, waist, groin, and skin folds, although any covered or sweaty area can be affected.

Skin redness and bumps are not specific to heat rash. Folliculitis, contact dermatitis, eczema, and infection can look similar. A rash that is very painful, blistering, spreading, or associated with fever needs a clinical assessment rather than repeated self-treatment.

Move to a cooler environment, take lukewarm showers, and pat the skin dry. Choose loose, breathable clothing and change out of sweaty garments. Reduce rubbing and avoid thick ointments, fragranced products, and scratching over the affected area. A light emollient may help irritated skin, while a topical corticosteroid should be used only with suitable medical advice, especially on the face, folds, or in children.

Arrange care if the rash does not improve after cooling and gentle skin care, keeps returning, or is difficult to distinguish from another skin rash. Seek prompt help for fever, marked pain, pus, warmth, rapidly spreading redness, blisters, facial swelling, or breathing difficulty. Babies, older adults, and people who are unwell should be assessed sooner when a widespread rash accompanies overheating.

Does this pattern fit heat rash, and could friction, a product, infection, or another skin condition be responsible? Which emollient or anti-inflammatory treatment is safe for this body area?