Heat rash (prickly heat)

Heat rash is uncomfortable but usually harmless. It should clear up on its own after a few days.

Check if you have heat rash

The symptoms of heat rash are:

  • small red spots
  • an itchy and prickly feeling
  • redness and mild swelling

The symptoms are often the same in adults and children.

It can appear anywhere on the body and spread, but it’s not infectious to other people.

Other rashes that aren’t heat rash

How you can treat or prevent heat rash

The main thing to do is keep your skin cool so you don’t sweat and irritate the rash.

To keep your skin cool:

  • wear loose cotton clothing
  • use lightweight bedding
  • take cool baths or showers
  • drink plenty of fluid to avoid dehydration

To calm the itching or prickly rash:

  • apply something cold such as a damp cloth or ice pack (for no more than 20 minutes)
  • tap or pat the rash instead of scratching it
  • don’t use perfumed shower gels or creams

Your pharmacist can help with heat rash

To help soothe sore and itchy skin you can:

  • use calamine lotion
  • use hydrocortisone cream (but not on the face)
  • take antihistamine tablets (but speak to a pharmacist first as they’re not always appropriate)

You can buy these from a pharmacy. The pharmacist can advise you on the best medicines to use, for example if you’re pregnant or a child has the rash.

See a GP if:

  • the rash doesn’t improve after a few days
  • your baby has a rash and you’re worried

Causes of heat rash

Heat rash is usually caused by excessive sweating.

Sweat glands get blocked and the trapped sweat causes a rash to develop a few days later.

Babies often get it because they can’t control their temperature as well as adults and children.

Sweating is usually caused by hot or humid weather but other things can cause it. For example, being overweight or spending long periods in bed, perhaps because of an illness.

Call 111

If you can’t speak to your GP or don’t know what to do next.