How to treat sweat rash

What does sweat rash look like?

Typical heat rash causes small, raised spots with an itchy or prickly feeling and sometimes mild swelling. Spots can contain fluid. The rash often looks red on white skin, but can look grey or white, or be harder to see, on brown or black skin. Symptoms are often similar in adults and children. Heat rash can spread across your body, but you cannot pass it to another person.4

Heat rash commonly develops where clothing restricts airflow or skin touches skin. In adults, that includes the chest, back, arms and inner thighs. Babies often develop it around the neck, armpits, elbow creases, groin, upper chest or back. Some heat rashes form clear, dropletlike bumps rather than an itchy red rash.2

What should I do first?

1. 1Move somewhere cooler, ideally an air conditioned room, and remove clothing covering the affected area.
2. 2Gently wash the skin with cool or lukewarm water. Pat it dry rather than scrubbing.
3. 3Leave the area uncovered when practical, or put on clean, loose clothing that does not rub.
4. 4Apply a cool, damp cloth when the skin feels prickly.

A cold compress or an ice pack wrapped in a tea towel can soothe the area for up to 20 minutes. Tap or pat itchy skin instead of scratching. Use cool baths or showers, lightweight bedding and loose cotton clothes to reduce further sweating. Drink plenty of fluid to avoid dehydration.4

Cooling and airflow do most of the work, which is an unusually modest job description for a skincare routine.2

Which creams or medicines help?

Cooling comes first; medicine is an option for symptoms that remain uncomfortable. A pharmacist can help choose between calamine lotion, antihistamine tablets and hydrocortisone cream. Avoid perfumed shower gels and creams while the rash heals.4

Hydrocortisone works by calming the body's immune response. For skin problems, hydrocortisone comes as creams, ointments or lotions; it also comes in other forms for entirely different health problems. Choose a preparation intended for skin and get advice on its use rather than treating every hydrocortisone product as interchangeable.5

What should I avoid while the rash heals?

Avoid layering moisturizers, ointments or powders onto the rash without advice. Products that block the skin can stop sweat escaping and make heat rash worse. Ask a pharmacist or clinician before using a topical treatment, especially if the itching is intense. Scratching can break the skin and allow infection.2

Avoid excessive soap and other irritants, tight clothing and clothing that stays wet against your skin. Change out of wet clothes and sleep in a cool, ventilated bedroom. Reducing both sweating and friction helps the rash settle; repeatedly washing with more soap is not the solution.3

How long does sweat rash take to clear?

Most cases settle within a day or two after moving to a cooler environment, though clearing can take a few days. Get medical advice if the rash has not improved after a few days instead of continuing to add products.34

How do I treat sweat rash in a baby or child?

Take your child to a cool place to stop the sweating. Heat rash usually goes away on its own within a few days, and cooling helps your child feel more comfortable. Call a pediatrician or dermatologist if the rash is still present after a few days. If you are unsure what the bumps are, have them checked: several childhood rashes look alike.6

Keep your baby cool and dry, with lightweight, soft cotton clothing during hot weather. Cotton absorbs moisture and keeps it away from the skin. If air conditioning is unavailable, a fan can help; place it far enough away that only a gentle breeze reaches your baby. Do not use baby powder to treat or prevent heat rash. Avoid creams and ointments, which tend to keep the skin warmer and block pores.7

How can I stop sweat rash coming back?

Sweat rash becomes more likely with hot, humid weather, intense exercise, fever and skin covered by tight or nonbreathable clothing. Newborns are particularly susceptible because their sweat ducts are immature. People confined to bed can also develop it where skin stays against waterproof mattress covers.3

Choose loose, breathable clothing and avoid excessive layers. Loose cotton clothing gives the affected area room to breathe, without requiring a wardrobe with a clinical name. Keep your sleeping space cool and remove wet clothes rather than leaving them against the skin.3

When should I get medical help?

See a clinician if the rash is painful, intensely itchy, repeatedly returns or does not improve after a few days. Swollen or warm skin, fever and chills can signal infection. Pus drainage also needs medical attention. If your baby has a rash and you are worried, contact a doctor.124

Dizziness, nausea, vomiting or a headache during heat exposure can indicate heat exhaustion, which needs immediate medical attention. Stop physical activity and move out of the heat while getting help. Confusion, changes in behaviour or slurred speech can indicate heat stroke, a medical emergency. Do not treat these symptoms as just a skin rash.1