Is sweat rash contagious?

Why does sweat cause a rash?

Heat rash develops when sweat glands become blocked and sweat gets trapped beneath the skin. Heavy sweating can lead to a rash a few days later. The rash usually improves on its own within a few days.1

Typical signs are small raised spots, itching or a prickly feeling, and mild swelling. Some spots contain fluid. The rash often looks red on white skin, but can look grey or white and be harder to see on brown or black skin. Adults and children often have similar symptoms.1

A rash after sweating is not always heat rash: sweating inside gloves can also cause irritant contact dermatitis, which is skin inflammation caused by irritation. Contact dermatitis is not contagious either. An itchy rash that keeps returning deserves assessment, because identifying and avoiding the cause is central to clearing contact dermatitis.23

How do you calm heat rash?

1. 1Cool your skin to reduce sweating and irritation. Wear loose cotton clothing and take cool baths or showers.
2. 2Use lightweight bedding to help keep skin cool, rather than giving the bed a winter wardrobe.
3. 3Apply a cool damp cloth, or an ice pack wrapped in a tea towel, for up to 20 minutes to ease itching.
4. 4Tap or pat the rash instead of scratching, and avoid perfumed shower gels and creams. Drink plenty of fluid to avoid dehydration.

Should you put cream on it?

A pharmacist can suggest treatment such as calamine lotion, antihistamine tablets or hydrocortisone cream. Children under 10 need a doctor's advice before using hydrocortisone. For a child's heat rash, start with cooling rather than lotions, oils, creams or ointments, which can block pores, trap moisture and worsen the rash.14

What if your baby or child has it?

Move your child into a cooler area, remove extra clothing and use a fan. Gently remove sweat and body oils with a cool damp washcloth, then dry excess moisture. In babies, heat rash commonly appears on the neck, armpits, elbow creases and groin; older children can also get it on the chest and back. A child with uncomplicated heat rash should behave normally and should not have a fever or other signs of illness.4

What makes it come back?

Hot, humid conditions, exercise, heavy clothing and fabrics that stop sweat evaporating can contribute. Dress children in breathable cotton and avoid overdressing them.4

Protective equipment can also trap heat by preventing sweat from evaporating, which is an unhelpful bonus feature. Sweating inside gloves and friction from equipment can irritate skin. At work, equipment needs the correct selection and fit for the hazard; skin irritation and overheating need attention without compromising protection. Begin cooling immediately if signs of heat illness develop.2

When should you get medical help?

See a doctor if the rash does not improve after a few days, gets worse, or your baby has a rash that worries you. For children, seek medical care for fever, chills, increasing pain, warmth or swelling around the rash, swollen glands, or acting unwell. Do not assume those symptoms are simply heat rash.14