Heat rash between the butt cheeks: what to know

The cleft is warm, covered and exposed to rubbing, so sweat can remain against the skin. Heat rash, also called prickly heat or miliaria, may look like tiny red, pink, brown or skin-coloured bumps. On deeper skin tones, redness may be harder to see; swelling, texture change, itch or burning can be more noticeable. Moisture and friction can also cause chafing or allow another rash to develop, so the appearance alone cannot confirm the cause.

Gently rinse with lukewarm water, pat the area completely dry and change out of damp underwear or clothing. Choose loose, breathable fabric and take breaks from prolonged sitting when practical. Avoid scrubbing, fragranced products, heavy occlusive ointments and powders that cake in the cleft. A bland moisturiser may support a damaged skin barrier; see Emollient Therapy for general guidance. Do not apply a steroid cream to broken, infected or uncertain skin without medical advice; a clinician can decide whether Topical Corticosteroids are appropriate.

Arrange medical advice if the area is spreading, persistently painful, cracked, wet, foul-smelling or not settling after removing heat and friction. Seek prompt care for pus, increasing warmth, marked swelling, fever, rapidly worsening pain or skin that becomes dark, grey or blistered. A clinician may distinguish heat rash from fungal infection, contact irritation, eczema or bacterial infection.

Ask what diagnosis best fits the bumps, whether a swab or examination is needed, which cleanser and moisturiser are suitable for this fold, and how long to try the plan before returning.