Varicella (chickenpox)

By Dr. Pascal Bafteh · last updated 09/2026

Definition & Pathogen

Primary infection with Varicella-zoster virus, double-stranded DNA virus of the family Herpesviridae.

• Primary infection → varicella (chickenpox)
• Reactivation → herpes zoster (shingles)

Clinical presentation

• Incubation: 10–21 days (mean 14 d)
• Prodrome: fever, headache, malaise
• Intensely pruritic exanthem: macule → papule → vesicle ("dewdrop on a rose petal") → pustule → crust
• Pathognomonic pattern of skin lesions: polymorphic with all stages simultaneously (starry sky) (Heubner starry sky)
• Distribution: starts on head/trunk, then centrifugal to limbs; scalp/capillitium involved
• Mucous membranes: mouth, genitals, conjunctiva

Complications

• Bacterial superinfection (most common): Staph. aureus, Streptococcus pyogenes → impetiginisation, erysipelas, necrotising fasciitis, sepsis
• Most dangerous pulmonary complication: varicella pneumonia (especially adults, pregnant women, immunocompromised)
• CNS complications:
• Cerebellitis (children, usually benign, "ataxic gait")
• Encephalitis (dangerous, high mortality)
• Aseptic meningitis
• Hepatitis, thrombocytopenia
• Reye syndrome as rare but threatening complication especially in children on ASA — therefore strictly avoid ASA!
• Pregnancy:
• Congenital varicella syndrome with infection in gestational weeks 8–20: skin defects/scars, limb hypoplasia, CNS defects, eye malformations
• Perinatal varicella (maternal disease 5 d before to 2 d after delivery): lethality up to ~30 %

Diagnostics

• Usually clinical
• If unclear: VZV-PCR from vesicle fluid (most sensitive)
• Serology (IgM, IgG) in pregnant women to clarify immune status

Differential diagnoses

• Eczema herpeticum
• Herpes simplex labialis
• Herpes zoster
• Impetigo
• Molluscum contagiosum
• Hand-foot-and-mouth disease
• Urticaria
• Ecthyma

Sources (selection)

1. Gershon et al. 2022 Nat Rev Dis Primers — Varicella zoster virus infection
2. Wreghitt et al. 1989 — Disseminated varicella in adults
3. Hurwitz et al. 1987 N Engl J Med — Reye's syndrome aspirin
4. Pastuszak et al. 1994 N Engl J Med — Outcome after maternal varicella infection
5. AWMF S2k Zoster 2019

More viral skin infections

• Herpes zoster
• Mpox
• Erythema infectiosum (fifth disease)

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.