Baby rash - what's normal and when to worry

Last reviewed: July 2026 | Sources: NHS

Babies and young children get rashes constantly - most are harmless and resolve on their own. The challenge is knowing which ones need medical attention. Here's a guide to the most common rashes and the one red flag every parent should know.

The glass test - the one thing every parent must know

If your child has a rash, press the side of a clear glass firmly against the skin. If the rash fades (blanches) under pressure, it's almost certainly not meningitis. If the rash does NOT fade - you can still see it clearly through the glass - call 999 immediately. This is a possible sign of meningococcal septicaemia and needs urgent treatment.

Note: the non-blanching rash is a late sign. If your child is unwell with fever, irritability, and drowsiness, don't wait for a rash to appear before seeking help.

Common harmless rashes

Heat rash (miliaria)

Small red bumps or tiny blisters, usually on the face, neck, and chest. Caused by blocked sweat ducts in warm weather or overdressing. Cool the skin, dress lightly, and it resolves on its own.

Baby acne

Red or white spots on the face, appearing in the first few weeks. Caused by maternal hormones and clears without treatment by 2-3 months. Don't squeeze or apply creams.

Cradle cap

Yellow, greasy, scaly patches on the scalp. Very common in the first few months. Gently massage with baby oil to soften, then brush out with a soft brush. It clears on its own.

Nappy rash

Red, sore skin in the nappy area. Caused by prolonged contact with wee or poo. Change nappies frequently, use a barrier cream (zinc oxide), and allow nappy-free time when possible. If it doesn't improve in a few days or has red spots spreading beyond the main rash, it may be fungal and need antifungal cream from your pharmacist.

Rashes that need attention

Chickenpox

Starts as small red spots that become itchy blisters within hours. Appears in waves over several days. Usually mild in children but they're infectious until all spots have crusted over (typically 5-7 days). Keep them comfortable with calamine lotion and paracetamol (not ibuprofen with chickenpox).

Impetigo

Red sores or blisters that burst and leave golden-brown crusts. Highly contagious. Needs antibiotic treatment from your GP.

Hand, foot and mouth disease

Small blisters on hands, feet, and in the mouth, often with a mild fever. Caused by a virus, not related to animal foot and mouth disease. Usually resolves in 7-10 days. Keep your child hydrated and offer soft foods if mouth sores are painful.

Call 999 if:

The rash doesn't fade when you press a glass against it (possible meningitis). Your child has a rash AND is unusually drowsy, has a stiff neck, is sensitive to light, or has a high-pitched cry. Call 999 even if you're not sure - it's always better to check.

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Sources

NHS - Rashes in babies and children · Meningitis Now - Signs and symptoms