Heat rash between legs: what to know

The legs may feel prickly, itchy or raw after heat, exercise or prolonged walking. Small bumps and a patchy rash can appear in the folds, while darker skin may show inflammation as brown, purple, grey or deeper colouring. The pattern does not by itself prove the cause: fungal infection, eczema and contact irritation can look similar.

Keep the folds cool and dry: rinse gently, pat rather than rub, and change damp clothing. Loose breathable garments reduce heat and friction. Avoid scented washes, deodorants applied to irritated skin and scratching. A simple moisturiser can support a dry, chafed surface; see [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/). Ask a clinician before using [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) in a fold.

Get medical advice if the rash spreads, keeps returning, cracks, oozes, smells unpleasant or becomes painful. Prompt assessment is needed for fever, rapidly increasing swelling, marked warmth or tenderness, pus or red streaks. If cooling and drying do not begin to settle it, an examination can distinguish heat rash from infection or another inflammatory condition.

Could this be heat rash or a fungal infection? Which cleanser and moisturiser suit this area? What changes would help during exercise, work or hot weather? If medicine is suggested, how long should it be used and what symptoms mean I should stop?