Varicella (chickenpox)
Also called chickenpox, primary VZV infection
Primary varicella-zoster infection: crops of intensely itchy lesions appearing in waves, so macules, papules, vesicles, and crusts share the skin at once, densest on the trunk, 'dewdrops on rose petals'. Mild in most children, meaner in adults, pregnancy, and immunocompromise.
How it looks
Numerous lesions in different stages, erythematous macules, papules, umbilicated vesicles on red bases, and crusts, scattered densely over the trunk and face.
Rose is the lesion, grey the pattern the lesions make, green where on the body it lives.
Across skin tones
The 'rose petal' erythema around vesicles is subtle in deeply pigmented skin, so the eruption reads as papulo-vesicles without the red halo, and it resolves with prominent, sometimes long-lasting, pigment change at every lesion site.
Don't miss
A varicella lesion that becomes suddenly hot, indurated, and much more painful heralds invasive group A streptococcal superinfection, the feared complication in children.
Symptoms & course
- Prodromal fever and malaise
- Intense itch through the vesicular phase
- New crops for 3-5 days; contagious until every lesion crusts
Diagnostic approach
- Clinical; PCR of vesicle fluid when atypical or high-stakes
- Check exposure history in pregnancy and immunocompromise urgently
Differential, and how to separate them
- Herpes zoster
Favours it: Vesicles on erythematous bases from the same virus
Against it: Zoster is one dermatomal band in someone with past varicella; chickenpox is generalized crops
- Impetigo
Favours it: Crusted lesions in a febrile child
Against it: Impetigo lacks the vesicular crops in multiple simultaneous stages and the centripetal density
- Scabies
Favours it: A widely itchy child
Against it: Scabies evolves over weeks with burrows and spared face, not febrile crops over days
Management principles
- Supportive care and antipruritics for healthy children; trim nails against excoriation and secondary impetigo
- Oral antivirals for adolescents, adults, and anyone at higher risk, ideally within 24 hours of the rash
- Immunocompromised or pregnant contacts and patients: urgent specialist advice, IV therapy or prophylaxis
Clinical pearl: Lesions in every stage at once separates varicella from almost everything else; smallpox-era teaching survives because the principle, one stage versus many, still sorts vesicular rashes.
Keep going
Try the case: Crops of spots, three days apartBack to the Atlas