Child health
AKT · Child health/Infection & rash
Chickenpox (varicella)
Varicella zoster virus (VZV)
Overview
Primary VZV infection: an itchy vesicular rash in successive crops at different stages (macule → papule → vesicle → crust), with mild systemic upset. Reactivation later causes shingles.
Recognise
- Crops of itchy lesions at DIFFERENT stages simultaneously (the discriminator)
- Starts on trunk/face → spreads; mild fever, malaise
- Infectious from 48h before rash until all lesions crusted
Red flags
- Secondary bacterial infection (GAS — necrotising fasciitis), pneumonitis, encephalitis (cerebellar ataxia), neonatal/immunocompromised/pregnant exposure
Differentials & how to tell them apart
Hand-foot-and-mouth (coxsackie)lesions on hands, feet and mouth, not generalised crops
Disseminated HSVPCR; immunocompromised
Impetigogolden crusts, localised
Smallpox (historical)all lesions at SAME stage — opposite of varicella
Investigations
Clinical. VZV PCR of vesicle fluid if needed. Check immunity in exposed pregnant women.
Management
Supportive (aciclovir if immunocompromised/neonate/severe)
- 1Healthy child: supportive — calamine, antihistamine, antipyretic; exclude until all lesions crusted.Gate: Immunocompromised, neonate, pregnant, or severe → aciclovir (and VZIG/antiviral post-exposure prophylaxis for vulnerable contacts)
- 2Avoid NSAIDs (skin sepsis risk) and exposure to pregnant women/immunocompromised/neonates.
Supportive (calamine, antihistamine) — most children
Aciclovir — immunocompromised, neonates, severe, or adults/adolescents within 24h
VZIG / aciclovir — post-exposure prophylaxis for vulnerable contacts (pregnant, immunocompromised, neonates)
Key points
The discriminating feature: lesions at DIFFERENT stages at once. Pregnant exposure and neonatal varicella are dangerous — give VZIG/antiviral prophylaxis.
Monitor & prognosis
Secondary infection, pneumonitis, neuro signs.
Self-limiting in healthy children; reactivates as shingles later.
Source: NICE CKS Chickenpox; UKHSA