Heat Rash in Babies: Causes, Photos & How to Treat | Parenting Hub
Heat rash in babies looks like tiny red or clear bumps on the neck, chest and back. Learn what causes it, how to cool your baby down and when to see a doctor.
Tiny red or clear bumps on your baby's neck, chest or nappy area are usually heat rash — uncomfortable but rarely serious. Here's how to cool them down and when to call a doctor.
What heat rash looks like
Heat rash (also called prickly heat or miliaria) shows up as clusters of tiny red, pink or clear fluid-filled bumps. You'll most often see it on the neck folds, upper chest, back, armpits and nappy area — anywhere skin traps sweat against skin or fabric.
Babies are more prone than adults because their sweat glands are still developing, so sweat gets blocked under the skin instead of evaporating. It's most common in summer, in warm car seats or carriers, and after a baby has been bundled up in too many layers.
What you can do at home
The aim is simple: cool the skin and let it breathe. Most heat rash settles in 24–48 hours once your baby is cooler.
- Move baby to a cooler room (ideally 20–22°C) and remove a layer of clothing.
- Dress in loose, single-layer cotton — skip synthetic fabrics.
- Pat (don't rub) the area dry after baths and feeds; trapped moisture makes it worse.
- Offer extra feeds — breastfed babies don't need water before 6 months, but they may want to nurse more often.
- Skip creams, powders and oils on the rash itself; they trap heat and can make things worse.
How long it lasts
Mild heat rash usually fades within a day or two of cooling baby down. Persistent bumps that don't change with cooling, or a rash that spreads to the face and limbs, may be something else — eczema, viral rash or an allergy — and is worth a check with your GP or maternal health nurse.
When to seek help
- Fever over 38°C in a baby under 3 months, or over 39°C at any age
- Rash with blisters, pus or weeping skin
- Baby is unusually drowsy, floppy, or won't feed
- Rash doesn't fade when you press a glass against it (could indicate a meningococcal rash — call 000)
Common questions
How can I tell heat rash from eczema?
Heat rash appears suddenly in warm conditions and clears within a day or two of cooling baby down. Eczema is dry, scaly and itchy, comes and goes over weeks, and usually shows on the cheeks, scalp and inside of elbows and knees.
Can I put cornflour or talcum powder on heat rash?
No. Powders cake when they get damp and block sweat glands further — they can make heat rash worse and aren't safe for babies to inhale.
Is it safe to use a cool wet washcloth?
Yes — a cool (not cold) damp cloth pressed gently against the rash for a few minutes can soothe the itch. Pat dry afterwards. Avoid ice or anything fridge-cold on a baby's skin.