Heat Rash (Prickly Heat): Causes, Quick Relief and Prevention

Heat rash is your skin’s reaction to sweat that can’t escape. It’s very common in hot, humid weather, in babies, and in anyone wearing tight clothing or PPE for long shifts. It usually clears within a few days once the skin cools down.

Imagine a hot week and a long shift in gown and gloves. When you finally undress, your chest, neck and back are covered in tiny red or skin-coloured bumps that prickle and itch like pins. A cool shower and a night in loose cotton, and by morning they’re already fading.

What heat rash looks like

• Small raised spots, sometimes tiny clear blisters
• An itchy or prickly, stinging feeling
• Usually on the neck, chest, back, armpits, groin or skin folds
• On darker skin, bumps may look skin-coloured, darker or greyish rather than red

Quick relief

• Cool the skin with a cool shower, fan or damp cloth
• Wear loose, breathable cotton and change out of sweaty clothes
• Avoid heavy creams that block pores; calamine lotion can soothe itching
• Ask a pharmacist about an antihistamine or mild steroid cream if itching is bad

For babies: don’t over-wrap them. Dress them in light layers, keep rooms comfortably cool and check the back of the neck to see if they’re too hot.

But when could it be something else?

See a doctor or nurse if the rash doesn’t improve in a few days, spots fill with pus or the skin becomes hot and painful, or there’s a fever. Get urgent help for any rash that doesn’t fade when you press a glass on it, or if someone in the heat becomes confused, faint or stops sweating, which can be heatstroke.

Sources: NHS (Heat rash), American Academy of Dermatology, World Health Organization (Heat and health). This guide is for general information and does not replace advice from your own nurse, doctor or pharmacist.