How to help a heat rash

What does heat rash look like?

Heat rash, also called prickly heat, happens when blocked sweat ducts trap sweat beneath the skin. It causes tiny bumps or small blisters, often with itching, burning or a prickly feeling. Bumps can look red on lighter skin or grey or white on darker skin. Covered areas and skin folds are common places for it to appear.12

What helps with heat rash?

1. 1Move into a cooler or air conditioned space 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 washcloth as needed to ease the prickly feeling.
5. 5While the rash heals, pause activities that make you sweat heavily and resist scratching, which can break the skin and lead to infection.

Fans, cool showers and air conditioning help keep skin cool, even though none comes in a serum bottle.3

Should you put cream on heat rash?

Skip routine moisturizers and products that block sweat from escaping. If itching is intense, ask a pharmacist or clinician about a suitable treatment, such as calamine, before applying it.14

Hydrocortisone is a steroid medicine that reduces inflammation, meaning swelling, along with itching and pain. Skin preparations are used for heat rash. It is an option for symptom relief rather than a replacement for cooling the skin.5

What if a baby has heat rash?

For babies, a cooler, less humid environment is the main treatment. Avoid ointments and creams that keep skin warmer and block pores. Powders are unlikely to help and can be inhaled, so keep them out of reach. Babies and young children get heat rash more often, although it can happen at any age.26

How can you stop it coming back?

Choose lightweight, loose cotton clothing rather than tight outfits, so getting dressed does not become an insulation project. Move outdoor exercise to the coolest part of the day or exercise indoors with air conditioning. Reducing heavy sweating helps lower the risk of another heat rash.3

When should you get medical help?

Seek medical advice if the rash does not improve after a few days, becomes painful or causes intense itching. Get it checked sooner for fever, chills, swelling or skin that feels warm to the touch.1

Yellow or green drainage and red streaks are also signs of infection. Severe pain or blisters around the eyes, mouth or genitals need assessment. Not every rash after hot weather is heat rash; mention any new soaps, lotions or cosmetics when you speak to a clinician.6

Contact your child's clinician for a rash in a baby younger than 3 months, blisters, fever or no improvement after 3 days of home care.2

Dizziness, nausea, vomiting or headache after heat exposure can signal heat exhaustion and need immediate medical attention. Confusion, unusual behaviour or slurred speech can signal heat stroke, a medical emergency. Move out of the heat and get emergency help rather than treating these symptoms as part of the rash.4

For a child who is unwell with a rash, seek emergency help for breathing difficulty, a stiff neck, confusion, sudden mouth or throat swelling, or a rash resembling bruises that does not fade when pressed with a glass. A child can be seriously unwell without a high temperature.7