How to deal with heat rash

What does heat rash look like?

Heat rash, also called prickly heat, happens when sweat gets trapped beneath the skin. It causes tiny bumps that can itch, burn or feel prickly. The bumps can look red on lighter skin and grey or white on darker skin. Some appear as tiny clear blisters. Covered areas and skin folds are common locations.1

What should I do now?

1. 1Move somewhere cooler, preferably with air conditioning, and remove clothing covering the rash.
2. 2Gently wash the area with cool or lukewarm water. Pat it dry rather than scrubbing.
3. 3Leave the area uncovered where practical, or wear clean, loose clothing that does not rub.
4. 4Apply a cool, damp washcloth as needed to ease the prickly feeling.
5. 5Pause workouts and other activities that cause heavy sweating until the rash is gone.

For itch relief, pat or tap the skin instead of scratching, and keep your nails clean, short and smooth. Keep showers brief and avoid perfumed soaps and deodorants on itchy skin. These are general ways to ease itching and reduce damage from scratching, rather than a treatment for trapped sweat.2

Should I put cream on heat rash?

Skip moisturizers and other products that block pores while heat rash heals. Cooling and airing out skin do most of the work, so the bathroom shelf can sit this one out. If itching is intense, ask a pharmacist or clinician whether a product such as calamine is appropriate before applying it.13

Medicines for summer rashes depend on the cause, so do not choose a steroid cream or antihistamine just because a rash appeared in hot weather. Tell the pharmacist where the itching is and about any other symptoms. If a rash seems linked to a medicine, discuss treatment options with your doctor or pharmacist.24

What if my baby has heat rash?

Keep your baby cool and dry, with lightweight, soft cotton clothing. If air conditioning is unavailable, a fan can help; position it far enough away to provide only a gentle breeze. Avoid baby powders, creams and ointments. Powders do not prevent or improve heat rash, and creams and ointments can keep skin warmer and block pores.5

How can I stop it coming back?

Limit time in hot, humid places and choose loose cotton clothing rather than tight or synthetic fabrics. Loose cotton is a sensible dress code here, however little ambition it shows for a workout wardrobe. Drink fluids to prevent dehydration during hot weather. Young children and older adults are especially vulnerable to heat illness, and certain medicines also raise the risk.46

When should I get medical help?

See a doctor if the rash does not improve after a few days somewhere cool, covers a large area or keeps returning. Get it checked for warmth, swelling, pus or fever, which can signal infection. Severe itching, pain or uncertainty about the cause also deserve assessment. During pregnancy, tell your GP or midwife about itching rather than assuming it is heat rash.124

Seek immediate medical care for dizziness, headache, nausea or vomiting after heat exposure: these can be heat exhaustion. Confusion, unusual behaviour or loss of consciousness can signal heat stroke and require emergency help. For a child with a rash, breathing difficulty, poor responsiveness or bruise like spots that do not fade under a glass also require emergency care.347