Varicella and Herpes Zoster

Key Features

Essentials of Diagnosis

• Varicella (chickenpox)

  • Exposure to varicella or herpes zoster 10–21 days previously; no prior history of varicella

  • Widely scattered red macules and papules concentrated on the face and trunk, rapidly progressing to clear vesicles on an erythematous base, pustules, and then crusts, over 5–6 days

  • Variable fever and nonspecific systemic symptoms

• Herpes zoster (shingles)

  • History of varicella

  • Dermatomal paresthesias and pain prior to eruption (more common in older children)

  • Dermatomal distribution of grouped vesicles on an erythematous base

General Considerations

• Primary infection with varicella-zoster virus results in varicella, which generally confers lifelong immunity, but the virus remains latent lifelong in sensory ganglia

• Herpes zoster, which represents reactivation of this latent virus, occurs in 30% of individuals at some time in their life

• Herpes zoster is a common problem in immunocompromised children and is also common in children who had varicella in early infancy (< 1–2 years old) or whose mothers had varicella during pregnancy

Clinical Findings

• A 1- to 3-day prodrome of fever, malaise, respiratory symptoms, and headache may occur, especially in older children

• Varicella

  • Systemic symptoms are mild followed by crops of red macules that rapidly become small vesicles with surrounding erythema (described as a "dew drop on a rose petal"), form pustules, become crusted, and then scab

  • Lesions occur in the scalp, and sometimes in the nose, mouth (where they are nonspecific ulcers), conjunctiva, and vagina

  • Magnitude of systemic symptoms usually parallels skin involvement

  • Pruritus is often intense

• Herpes zoster

  • The unilateral, dermatomal vesicular rash and pain of herpes zoster is very distinctive

  • Ophthalmic zoster may be associated with corneal involvement

  • The closely grouped vesicles, which resemble a localized version of varicella or herpes simplex, often coalesce

  • Crusting occurs in 7–10 days

  • Postherpetic neuralgia is rare in children

Diagnosis

Laboratory Findings

• Leukocyte counts are normal or low

• Leukocytosis suggests secondary bacterial infection

• Virus can be identified by fluorescent antibody staining of a lesion smear

• Polymerase chain reaction is definitive when identifying the etiology is critical (eg, atypical disease in immunocompromised children)

• Serum aminotransferase levels may be modestly elevated during typical varicella

Imaging

• Radiography

  • Varicella pneumonia classically produces numerous bilateral nodular densities and hyperinflation; seen more often in immunocompromised than in immunocompetent children

Treatment

General Measures

• Supportive measures

  • Maintenance of hydration

  • Administration of acetaminophen for discomfort

  • Cool soaks or antipruritics for itching (diphenhydramine, 1.25 mg/kg every 6 hours, or hydroxyzine, 0.5 mg/kg every 6 hours)

  • Observance of general hygiene measures (keep nails trimmed and skin clean)

• Care must be taken to avoid overdosage with antihistaminic agents

• Topical or systemic antibiotics may be needed for bacterial superinfection

Specific Measures