Heat rash on the vulva: what to know

Heat rash, also called miliaria, develops when sweat cannot move freely through irritated or blocked sweat ducts. Tight underwear, pads, exercise, humid weather, and sitting in damp clothing can add rubbing. The rash usually affects the outer vulval skin rather than the vagina. It may feel itchy, prickly, or tender.

A rash in this area can also come from contact irritation, thrush, bacterial infection, or a sexually transmitted infection. Burning with urination, unusual discharge, blisters, open sores, or marked swelling makes heat rash less certain. Related descriptions include Skin Rash and Skin Redness.

Gently rinse with lukewarm water, pat dry, and keep the area cool and aired. Change out of sweaty clothes promptly and choose loose, breathable underwear. Avoid fragranced washes, deodorant sprays, scrubbing, and powders on the vulva; do not scratch or squeeze bumps. A cool, clean compress held briefly against the outer skin may calm discomfort.

If the skin feels dry or chafed, a plain, fragrance-free emollient may protect the surface, but keep products away from the vaginal opening unless a clinician advises otherwise. Do not use a steroid cream on genital skin without medical guidance; topical corticosteroids need the right strength and duration for this sensitive area.

Arrange medical advice if the rash spreads, becomes increasingly painful, produces pus, or does not begin settling after cooling and removing friction. Seek prompt care for fever, rapidly increasing swelling, severe pain, blisters, ulcers, or trouble passing urine. A clinician can examine the skin and test for infection when the appearance or symptoms do not fit heat rash.

Could this be contact irritation, thrush, or another vulval condition? Which products are safe for the outer skin, and how should I use them? What changes would mean I need a swab or an urgent review?