Paediatrics: Rash: chickenpox and zoster

Rash: chickenpox and zoster

VZV infection typically occurs between the ages of 1 and 6yrs, with the maximal transmission during winter and spring.

Signs and symptoms

•   Prodrome: VZV is spread by respiratory droplets or direct contact with lesions. The infectious period begins 2 days before vesicles appear and ends when the last vesicle crusts over (it is possible to retrieve virus from a crust).

•   Rash: usually starts on the head and trunk; then the rest of the body. Individual lesions start as red macules, then progress through stages: papule, vesicle, pustule, crusting. Different stages of the rash are seen at the same time and heal completely within 2wks.

•   Other features. Headache, anorexia, signs of upper respiratory tract infection (i.e. sore throat, cough coryza), fever, and itching.

Diagnosis

•   Clinical. Characteristic rash, its distribution, and progression.

•   Other. Serology (VZV IgM), electron microscopy of vesicle fluid.

Management

•   Symptoms: treatment of fever and itching.

•   School exclusion: 5 days from start of skin eruption

•   Antivirals: aciclovir is used in severe varicella, encephalitis, pneumonia, babies, and immunosuppressed patients (i.e. steroids, oncology, etc.).

•   VZIG: Varicella zoster immunoglobulin should also be considered as prophylaxis following contact in at risk individual (see www.hpa.org.uk for guidance).

•   Immunization: from age 1 not currently part of UK schedule

Complications

s bacterial infection may occur with invasive group A streptococcus lead-ing to necrotizing fasciitis or toxic shock syndrome. Other rare complica-tions include purpura fulminans, cerebrovascular stroke, and encephalitis. Life-threatening pneumonitis may occur in the young infant and immuno-suppressed child.

Herpes zoster (shingles)

A reactivation of latent infection may occur, leading to vesicular lesions in the distribution of a sensory nerve. Rare in childhood, but occurs in the immunosuppressed, or in those who had p infection in infancy.