Is heat rash contagious?

Why can heat rash spread on your body?

Heat rash can appear anywhere on the body and spread across your skin without being contagious. Continued heat, humidity and sweating encourage it, especially beneath clothing that traps heat. Exercise, fever and tight clothing can also contribute. More affected skin does not mean you are passing the rash to other people.13

Typical symptoms are small raised spots, an itchy or prickly feeling and mild swelling. Some spots contain fluid. The rash can look red on white skin, or grey or white and less obvious on brown or black skin. Adults and children often have similar symptoms. Heat rash is also called prickly heat or miliaria, giving one sweaty problem a surprisingly generous naming budget.13

How do you help heat rash clear?

Cooling the skin is the main treatment, which gives the bathroom shelf less to do than usual. Reduce sweating and irritation rather than adding more products to the rash.3

1. 1Move somewhere cooler and limit time in the heat. Rest in a cool, ventilated room and change out of wet clothing.
2. 2Wear loose cotton clothing and use lightweight bedding. Take a cool bath or shower to help cool your skin.
3. 3For itching, apply a cool damp cloth or an ice pack wrapped in a tea towel for up to 20 minutes. Tap or pat the rash rather than scratching.
4. 4Avoid perfumed shower gels and creams, and avoid excessive soap. Ask a pharmacist about treatment if the discomfort continues.

A pharmacist can suggest calamine lotion, antihistamine tablets or hydrocortisone cream. Children under 10 need advice from a doctor before using hydrocortisone. Babies get heat rash more often because they cannot control their temperature as well as older children and adults.1

Most heat rash clears within a day or two after moving to a cooler environment, although it can take a few days. See a doctor if the rash does not improve after a few days, or if your baby has a rash and you are worried.13

When should you get the rash checked?

Heat rash can develop a secondary bacterial infection. Contact a healthcare professional if the skin feels warm or drains pus. Seek immediate medical care if heat exposure also causes dizziness, nausea, vomiting or headache; heat exhaustion needs prompt treatment.23

Not every rash after sweating is heat rash. Intertrigo is inflammation from skin rubbing together in moist folds, such as the armpits or groin. Intertrigo itself is not contagious, but it can develop an infection. Fungal infections and bacterial folliculitis, an infection around hair follicles, can also resemble heat rash. An uncertain diagnosis or a persistent rash deserves an examination rather than an assumption based on hot weather.234