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Nappy rash differential diagnosis

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2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Unwell infant or destructive eruption

Fever or hypothermia, lethargy, poor feeding, dehydration, rapidly spreading erythema, severe pain, bullae, purpura, necrosis, grouped vesicles in a neonate, urinary obstruction or extensive skin loss suggests sepsis, invasive bacterial disease, neonatal herpes or another serious disorder.

Action: Arrange immediate paediatric assessment, protect temperature and hydration, obtain cultures and viral samples only if they do not delay treatment, and begin age-specific sepsis, antibacterial or antiviral care with safeguarding and infection-control input where indicated.

Synopsis

Distinguish irritant napkin dermatitis from candidal, inflammatory, bacterial and systemic mimics, examine an infant respectfully, use age-safe topical treatment, and escalate persistent or unwell presentations promptly.

  • Irritant napkin dermatitis affects convex surfaces in contact with urine and stool and typically spares the deepest groin folds.
  • Candida produces a confluent red, red-brown or violaceous plaque that involves folds and has satellite papules or pustules beyond the main edge.
  • Seborrhoeic dermatitis reaches folds with greasy scalp, brow or ear scale, while napkin psoriasis is sharply demarcated, smooth and persistent with scale reduced by moisture.

Key red flags

Systemic illness, rapidly advancing inflammation, vesicles in a neonate, purpura, necrosis, severe pain, bleeding, failure to thrive, diarrhoea with periorificial or acral lesions, treatment resistance, hepatosplenomegaly or recurrent unusual infection requires urgent paediatric review.

Neonatal herpetic eruption

Grouped same-sized vesicles, punched-out erosions or crust in a neonate, especially with poor feeding or fever, is an antiviral emergency.

Investigation priorities

01
Whole-skin and growth assessmentFirst step

Confirm distribution and identify inflammatory or systemic disease beyond the napkin area.

Management branches

First-line irritant careBreak contact, friction and occlusion

Convex erythema spares folds and the infant is otherwise well.

  1. Change wet or soiled nappies promptly, rinse with lukewarm water and soft material or use fragrance- and alcohol-free wipes when water is impractical, then pat rather than rub dry.
  2. Allow supervised nappy-free time and apply a thick fragrance-free barrier preparation at every change, removing only visible soiling instead of scrubbing all residue away.
First-line Candida careTreat yeast and its wet habitat

The plaque enters folds and satellite papules or pustules make Candida clinically likely.

Key medicines

Hydrocortisone 1% for inflamed napkin skinFor an infant when prescribed, apply a very thin layer once daily to inflamed skin for no more than 7 days, then stop; continue barrier care at separate application times.
Clotrimazole 1% creamApply a thin layer two or three times daily to candidal fold and satellite lesions for at least 2 weeks according to the licensed product and clinical response.
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom