Heat rash in newborns: what to do

Heat rash appears when sweat and heat irritate the skin. In newborns it can look like tiny bumps or small blisters, often on the neck, chest, back, folds or areas covered by clothing.

It often improves by cooling the baby and reducing humidity and layers, but not every rash should automatically be considered heat rash.

What it may look like

Heat rash can cause:

• red or pink dots;
• small superficial blisters;
• rash in folds, neck, chest or back;
• worsening with heat, sweat or heavy clothes;
• a baby who may be uncomfortable but not necessarily ill.

If your baby has fever, seems weak or the rash does not change after cooling, be cautious.

What to do

• Check that your baby is not overdressed.
• Use light, breathable clothing.
• Keep the room comfortable.
• Avoid prolonged sweating.
• Wash gently if the skin is sweaty.
• Pat dry.
• Leave irritated areas uncovered when possible.

For home environment and temperature, home safety can help you think through spaces and habits.

What to avoid

• Do not use talcum powder.
• Do not cover the rash with heavy occlusive creams unless advised.
• Do not use fragrances or essential oils.
• Do not overdress your baby because you are afraid of cold.
• Do not place your baby in direct sun to dry the skin.

When to call the pediatrician

Call if:

• the rash spreads quickly;
• fever or illness signs appear;
• there are blisters, pus, crusts or swelling;
• your baby is under 3 months and seems different from usual;
• the rash does not improve after reducing heat and sweat;
• spots do not fade when pressed.

For other common patterns, read newborn acne and cradle cap.

Useful links

• Home safety
• Newborn acne
• Cradle cap
• Diaper rash
• Newborn skin checklist