Sweat rash between the buttocks: what to know

Heat rash, also called prickly heat or miliaria, may appear as itchy or prickling redness, tiny bumps or small fluid-filled spots in a warm skin fold. Damp clothing, prolonged sitting, exercise and skin rubbing can keep the area irritated. A rash in this location can also resemble a fungal infection, contact irritation or another skin condition, so appearance alone cannot confirm the cause.

Rinse with lukewarm water and a mild, fragrance-free cleanser, then pat dry rather than rubbing. Change out of sweaty underwear or sportswear promptly and choose loose, breathable fabric. Keep the fold cool, and avoid scratching, tight clothing, perfumed products and thick occlusive ointments. A simple [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) product may protect dry, chafed surrounding skin, while [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) should be used in this sensitive area only with suitable medical advice. More background is available in [Heat Rash](/conditions/heat-rash/).

Arrange a clinical assessment if the rash is spreading, very painful, repeatedly returning, draining fluid, developing crusts or not settling after cooling and careful skin care. Seek prompt help for fever, rapidly worsening redness, marked swelling, or feeling unwell. Painful blisters, sores or a rash involving genital skin also deserve an examination because they may need a different treatment.

Ask whether the pattern fits heat rash or another fold rash, whether any product should be stopped, and which treatment is safe for the buttock crease. Mention recent sweating, new underwear, exercise, medicines and whether itching, pain, discharge or blisters are present.