Updated 15 February 2016

Prickly heat

Prickly heat is a skin rash that children get when they're very hot.



  • Prickly heat is also called heat rash.
  • It is a skin rash, which appears in response to the child being very hot
  • It is most noticeable in folds in the skin and parts of the body where clothing fits snugly
  • Prickly heat is not a serious condition

Alternative names

heat rash, miliaria

What is prickly heat (heat rash)?

Prickly heat (heat rash) is a skin rash which appears in response to the child being very hot – in fact he or she may be too hot.

It is a pimply, red skin eruption, which can appear when your child overheats in hot or humid weather. It is most noticeable in folds in the skin and on parts of the body where clothing or nappies fit snugly, such as the chest, back, stomach, neck, genital area and buttocks. It may also spread across the head and forehead if your child wears a hat.

What causes heat rash?

Heat rash seems to appear when the child is sweating a lot. It is possible that there is some sort of irritation of the skin when the child sweats so much that the pores clog up and sweat cannot be released as fast as it builds up.

Tight, or heavy clothing can trap sweat, and contribute to the rash. Heat rash can also occur if the child has a high fever and is perspiring heavily.

Can heat rash be prevented?

Keep your child comfortably cool and avoid dressing him or her in tight fitting clothing in hot weather. Some people believe that natural fabrics such as cotton allow easier movement of air across the skin and cause less sweating than artificial fibres.

If it is very hot, make sure that your child plays inside or in the shade. Give him or her plenty of liquids to prevent dehydration.

Corn starch or talcum powder in skin creases can also help to prevent heat rash.

How is heat rash treated?

Start by cooling your child down. Loosen or remove tight clothing and move him or her into a cool, shady place. Cool the area affected by the rash with cotton clothes soaked in cool water. A tepid bath can also help. Let the air dry the skin as much as possible and avoid using towels since the rubbing may furter irritate the skin.

Avoid ointments or lotions since they can trap sweat and exacerbate the situation.

What is the outcome of heat rash?

Heat rash is not a serious condition and in most cases the child will get better without specific treatment.

There may be very superficial peeling of the affected skin area as the rash gets better.

When to call the doctor

Call your doctor if your child has a fever which does not respond to medication or other cooling techniques.

If the rash does not disappear in three to four days, take your child to the doctor to check the diagnosis.

(Reviewed by Prof H.F. Jordaan)


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