Varicella (Chickenpox)

Varicella is primary VZV infection—acute contagious dermatosis with mild systemic symptoms and crops of macules/papules/vesicles/crusts on skin/mucosa. Children; highly contagious; confers lifelong immunity (but zoster later).

Common Symptoms

Macule; forehead papules; intense pruritus; pustule; restlessness; low fever; cyanosis

Causes and Pathogenesis

VZV (Herpesviridae, α-subfamily), 150-200 nm, lipoprotein bilayer envelope; single serotype; human-only; fragile outside body (quickly inactive in dry crusts; stable in vesicle fluid at -65°C). Grows in human embryo fibroblasts, not chick embryo. Universal susceptibility, preschoolers most; infants <6 months protected by maternal antibody; pregnancy can infect fetus. Reservoir: varicella patients (infectious 1-2 days before rash until crusting). Pathogenesis: URT epithelial replication → viremia → disseminated skin lesions (spongiosis of stratum spinosum, multinucleated giant cells, eosinophilic intranuclear inclusions, thin-walled vesicles). Late vesicles turbid/pustular; superficial healing—usually no scar. Can involve eye/nose/oral/pharyngeal mucosa; also lungs/liver/spleen/adrenal/GI/heart/pancreas/CNS. Varicella pneumonia = diffuse interstitial pneumonitis with focal necrosis; varicella encephalitis = degeneration/necrosis/petechiae/demyelination. Epidemiology: highly contagious; respiratory droplets/direct contact; winter-spring; 2-10 years; ~90% attack rate in susceptibles.

Treatment

Drug therapy, supportive therapy

Preventive Measures

Handwashing; ventilation; avoid public places during epidemics. Vaccine recommended ≥1 year (10-30% incomplete protection but attenuates). Isolate cases; observe contacts 3 weeks; Ban-Lan-Gen granules 1 sachet/day × 3-5 days; Ig within 4 days for frail. Uncomplicated varicella has excellent prognosis; severe cases (immunocompromised/neonatal/disseminated/encephalitis) have 5-25% mortality; survivors of encephalitis may have mental retardation/seizures.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.