Quick answer: Baby skin is sensitive and reactive — rashes are one of the most common reasons parents call their health visitor or paediatrician.
Baby skin is sensitive and reactive — rashes are one of the most common reasons parents call their health visitor or paediatrician. While most baby rashes are benign and self-resolving, a few require urgent attention. Here’s a guide to the most common ones.
The Tumbler Test: A Critical First Check
Before anything else: if your baby has a rash, press a clear glass tumbler firmly against it. If the rash fades (blanches) under pressure, it’s not a meningococcal rash. If the rash does not fade (non-blanching), seek emergency care immediately — this can indicate meningococcal disease or septicaemia. This test applies regardless of the rash’s appearance.
Erythema Toxicum Neonatorum
Affects approximately 50% of newborns. Appears within the first 2–3 days. Looks like red blotches with a small white or yellow centre, scattered across the face, trunk, and limbs but sparing the palms and soles. It’s completely harmless, requires no treatment, and resolves within 1–2 weeks. No one knows exactly why it occurs.
Milia
Tiny white bumps on the nose, chin, and cheeks of newborns — present in approximately 40–50% of babies. They’re blocked sebaceous gland ducts containing keratin. They require no treatment and resolve spontaneously within weeks. Don’t squeeze or pick them.
Baby Acne (Neonatal Acne)
Appears at 2–6 weeks on the face. Small red and white papules/pustules on cheeks, forehead, and chin. Caused by maternal hormones. Resolves spontaneously by 3 months with no treatment. Don’t apply adult acne products.
Eczema
Dry, rough, itchy patches typically on cheeks, neck, and joint creases. Appears from 2–4 months. Managed with regular emollient and topical steroids for flares. Tends to improve with age. (See full eczema guide for complete management.)
Nappy Rash
Red, irritated skin in the nappy area from skin contact with urine and stool. Treated with barrier creams (zinc oxide, white soft paraffin), frequent nappy changes, and nappy-free time. Nappy rash that has satellite lesions (small spots around the main rash) or doesn’t respond to barrier cream within 3–4 days may be thrush — requires antifungal cream.
Chickenpox (Varicella)
Starts with red spots that become fluid-filled blisters, then crust over. Appears in crops over 3–5 days. Intensely itchy. Spreads from the trunk to the face and limbs. Contagious from 2 days before the rash until all blisters have crusted. Manage with paracetamol, calamine lotion, and antihistamine for itch. Avoid ibuprofen (associated with severe secondary bacterial infection in chickenpox).
Slapped Cheek (Fifth Disease / Parvovirus B19)
Distinctive bright red flushing on both cheeks (‘slapped cheek’ appearance), followed by a lacy net-like rash on the trunk and limbs. By the time the rash appears, the child is no longer contagious. Generally mild. Risk to pregnant contacts — parvovirus B19 can cause foetal anaemia in the second trimester. Inform any pregnant contacts.
Heat Rash (Miliaria)
Tiny red bumps or clear blisters from sweat duct blockage in hot, humid conditions. Common in skin folds. Resolves with cooling — move to a cooler environment, remove excess clothing, apply cool flannel.
Frequently Asked Questions
My baby has a red rash with a temperature — should I go to hospital?
Do the tumbler test. If the rash is non-blanching, go to hospital immediately. If it blanches, the combination of rash and fever still warrants a call to your GP or out-of-hours service the same day. Don’t wait overnight to see if it improves.
How do I know if a rash is infected?
Signs of secondary bacterial infection in a rash: increasing redness and warmth spreading beyond the original area, yellow or green crusting, pus, red streaking from the rash (lymphangitis), significant swelling, or fever developing or worsening alongside the rash. These require medical attention.
Can I send my baby to daycare with a rash?
Depends on the rash. Eczema, nappy rash, milia, and baby acne are not contagious — daycare is fine. Active chickenpox, HFMD blisters, or any undiagnosed rash with fever should be kept home until evaluated. Inform your nursery when you’re uncertain — they have policies and the information helps other families.
Related Reading
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