Chickenpox

Chickenpox is caused by primary infection with varicella zoster virus. Shingles is reactivation of dormant virus in dorsal root ganglion.

Chickenpox is highly infectious

• Spread via the respiratory route
• Can be caught from someone with Shingles
• Infectivity = 4 days before rash, until 5 days after rash first appeared
• Incubation period = 10-21 days

Clinical features (tend to be more severe in older children/adults)

• Fever initially
• Itchy rash starting from head/trunk before spreading. Initially macular then papular then vesicular
• Systemic upset is usually mild

Management is supportive

• Keep cool, trim nails
• Calamine lotion
• School exclusion: current HPA advice is 5 days from start of skin eruption
• Immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops then IV aciclovir should be considered

A common complication is secondary bacterial infection of the lesions. Rare complications include

• Pneumonia
• Encephalitis (cerebellar involvement may be seen)
• Disseminated haemorrhagic chickenpox
• Arthritis, nephritis, and pancreatitis may very rarely be seen