Nappy Rash
Why nappy rash happens, how to treat the common type at home, and the signs that mean it's thrush or something else.
- Last reviewed
- Sources cited
- 5 sources
- Author
- Dr Jubal John, FRACP
- Category
- medical guides
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Take-home
Nappy rash is usually caused by skin-contact with urine and stool in a warm, damp environment. The usual fix is frequent nappy changes, gentle cleansing, barrier cream, and nappy-free air time. If it doesn’t improve in 3–5 days, or looks different (deep red, shiny, with satellite spots), think thrush and ask for a review.
Why does nappy rash happen?
The nappy area is a small greenhouse: warm, moist, and often pressed against irritants. Three things typically combine:
- Irritant dermatitis: urine and stool (especially diarrhoea) break down the skin barrier
- Friction: from movement and poorly-fitting nappies
- Occlusion: the nappy traps moisture against the skin
Most babies get at least one episode in the first year. It’s almost never a sign of poor care.
Irritant vs candidal: distribution is the clue
The most useful diagnostic question isn’t “how red is it?”, it’s where does the rash sit? Irritant rash is on the convex skin that touches the nappy and spares the deep folds. Candidal (thrush) rash is deeper red, goes into the folds, and shows satellite spots scattered just outside the main patch.
The common type: irritant nappy rash
Pink or red on the convex surfaces, buttocks, thighs, genitals, lower abdomen. Mild scaling or slight shininess. Not usually painful unless severe. No pus, no vesicles, no fever.
The treatment plan: five steps
- Change nappies often: every 2–3 hours in the day, and once overnight if baby wakes. Don’t let a soiled nappy sit.
- Clean gently: warm water and cotton wool, or fragrance-free wipes. No soap in the acute phase.
- Pat dry: no rubbing. Air-dry for a few minutes if you can.
- Apply a thick barrier: a zinc-based barrier paste on every change (your pharmacist can point one out). “Applied like icing on a cake”, you should not be able to see the skin through it.
- Nappy-free time: 10–20 minutes a few times a day on a towel/waterproof mat. Airtime is the single biggest underused treatment.
Most irritant rashes resolve in 3–5 days with this regimen. Keep the barrier cream going for another few days after it clears.
When it’s not just irritant: nappy thrush (candida)
Persistent nappy rashes often become colonised with candida (thrush), especially after antibiotics or if the rash has been present for several days (RCH nappy rash).
Signs of nappy thrush
- Deep red (beefy) colour, often with a glazed or shiny surface
- Involves the deep skin folds (opposite of irritant pattern)
- Satellite lesions: small red spots just outside the main rash
- Doesn’t improve with good barrier care
- Often with oral thrush (white patches inside the mouth) or maternal nipple thrush in breastfed babies
Treatment
A topical antifungal, clotrimazole, miconazole, or nystatin cream, applied 2–3 times daily for 7–10 days, on top of the barrier cream. If there’s oral thrush, treat both to prevent ping-pong reinfection. Your GP or pharmacist can advise; prescription is usually not needed.
Less common, worth knowing about
Bacterial infection
- Pus, oozing, fever, or bright red spreading edge
- Needs topical or oral antibiotics, see your GP
Seborrhoeic dermatitis
- Greasy, yellow scales, also on scalp (cradle cap) and behind ears
- Improves with gentle shampoo + moisturiser; see Cradle Cap
Allergic contact dermatitis
- Sudden worsening after a new wipe, cream, or nappy brand
- Fix is removing the offender; try fragrance-free products
Eczema
- Also elsewhere on the body (cheeks, arms, behind knees)
- Family history of atopy
- Manage per Eczema Management
When to seek help
Green — usually fine
Green: manage at home
- Pink/red rash on exposed skin, baby otherwise well
- Improving day by day with frequent changes + barrier cream
- Gone within a week
Amber — be alert
Amber: book a review
- Rash not improving after 5 days of good care
- Deep red, shiny, or involving skin folds (suspect thrush)
- Recurrent nappy rash despite good routine
- Skin breakdown or bleeding
Red — act now
Red: seek same-day review
- Rash + fever, lethargy, or unwell baby
- Spreading red edge, pus, or weeping ulcers
- Blisters or a rash that looks burn-like
- Rash not in the classic distribution (suggests another diagnosis)
Prevention: the low-effort routine
What works
- Size up if the nappy leaves deep marks on skin
- Double-check at night if baby feeds through the night, extra overnight nappy or an overnight-specific brand
- Nappy-free time as a daily default, not a last resort
- Barrier cream on every change: zinc-oxide based, on stool-exposed skin
- Fragrance-free wipes or water + cotton wool in the first months
- Avoid talc: not recommended; inhalation risk and no benefit
Common questions
“Can I use cloth nappies?”
Yes. Cloth nappies don’t increase rash risk if changed as frequently as disposables. Some babies do better on cloth (more feedback when wet → more frequent changes), some better on disposables (more wicking). Neither is inherently better for skin.
“Should I use cornflour or baby powder?”
No. Cornflour can feed candida, and talc powder carries inhalation risk. Barrier creams and air do the job.
“My baby’s bottom is clean: why the rash?”
Because the chemistry matters more than the visual cleanliness. Urine + stool enzymes break down skin even in a freshly changed nappy if there’s no barrier. A clean bottom with no cream is still a bottom at risk.
“Is it because we changed detergent?”
Sometimes. Strong detergents can irritate cloth nappies or clothes. A fragrance-free, hypoallergenic detergent is the safest default.
Related reading
Nappy rash not improving?
See your GP or MCH nurse: a review usually tells whether it's irritant, thrush, or something else (photos of how it's changed help). Five-day rash = time to ask.