Heat Rash in Babies: Keeping Skin Cool and Comfortable

Small prickly bumps after a warm day or extra layers may be heat rash. Sweat can become trapped when sweat ducts are blocked, irritating the skin. Babies are more vulnerable to overheating because they cannot manage temperature as effectively as adults.

Heat rash usually settles after the skin stays cooler, but not every rash in warm weather is heat rash. A baby who is unwell needs assessment even if the spots appeared after sweating.

Reduce the heat around your baby

Move to a comfortably cooler place and remove unnecessary layers. Loose, lightweight clothing is easier to adjust than several thick layers. Keep young babies out of direct sun. Use a suitable pram shade rather than covering the pram with a blanket or muslin, which can trap heat.

Check the chest or tummy rather than adding clothes because hands or feet feel cool. Sweating or a hot tummy can mean your baby needs fewer layers. Our newborn clothing guide explains these checks in more detail.

For sleep, choose clothing and a suitable sleep bag for the room conditions. Do not put ice packs, cooling pads or damp towels in the cot. Keep the head uncovered indoors and retain your usual safe sleep setup, with your baby on their back on a clear, firm, flat sleep surface.

Soothe the skin gently

Heat rash may look like small raised bumps, with mild swelling or a prickly feeling. It can be less visibly red on brown or black skin. Feeling the texture and noticing discomfort can be more useful than looking for one particular colour.

A cool damp cloth held briefly against an affected area while your baby is awake and supervised may help. Do not put ice directly on the skin or chill your baby. If you bathe them, use comfortably lukewarm water, stay with them and pat dry gently. Scratching, rubbing and perfumed products can add irritation.

Ask a pharmacist or clinician before applying a medicine. Advice about adult antihistamines or hydrocortisone does not automatically apply to an infant. For ordinary dryness alongside the rash, the baby skin care guide can help you prepare questions about a suitable product.

Continue milk feeds

Offer breast milk or correctly prepared formula regularly, following feeding cues. An exclusively breastfed baby under six months does not need water added for hot weather, but may want to feed more often. Do not dilute formula or replace milk feeds with water.

For a young baby having formula, ask your health professional about any extra water in hot weather. Advice depends on age and circumstances. Watch for fewer wet nappies, poor feeding or unusual sleepiness rather than assuming that a baby is hydrated because they took one feed. The dehydration guide explains when to seek help.

Do not explain away a fever

Contact a clinician if the rash does not improve over a few days, becomes painful or swollen, develops discharge, or worries you. Seek urgent advice sooner if feeding decreases or your baby seems unwell.

A baby under three months with a temperature of 38°C or higher needs immediate assessment. Breathing difficulty, marked drowsiness, floppiness, blue or grey colouring, or a rash that does not fade under pressure requires emergency help. Cooling the room should never become a reason to postpone assessment of these symptoms.