NHS Factsheet

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Heat rash (prickly heat)

Read about heat rash, also called prickly heat or miliaria rubra, which is an itchy rash of small, raised spots and a stinging or prickling sensation on the skin.

18 November 2021

Introduction

Heat rash is uncomfortable, but usually harmless. It usually gets better on its own after a few days.

Check if you have heat rash

The symptoms of heat rash are:

  • small, raised spots
  • an itchy, prickly feeling
  • mild swelling

The rash often looks red, but this may be less obvious on brown or black skin.

The symptoms of heat rash are often the same in adults and children.

It can appear anywhere on the body and spread, but it cannot be passed on to other people.

Look at other rashes in children ↗.

How you can treat or prevent heat rash yourself

The main thing to do is keep your skin cool so you do not 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 feeling

  • apply something cold, such as a damp cloth or ice pack (wrapped in a tea towel) for up to 20 minutes
  • tap or pat the rash instead of scratching it
  • do not use perfumed shower gels or creams

A pharmacist can help with heat rash

Speak to a pharmacist about heat rash. They can give advice and suggest the best treatment to use.

A pharmacist might recommend:

Find a pharmacy ↗

See a GP if:

  • the rash does not 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 leads to a rash developing a few days later.

Babies often get heat rash because they cannot control their temperature as well as adults and children can.