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Chickenpox (Varicella) in an 8-Year-Old Child

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Causative Agent

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Epidemiology

• Humans are the only source; highly contagious via direct contact with lesions or airborne spread
• Incubation period: 10-21 days (usually 14-16 days); extended up to 28 days after VZIG
• Contagious from 1-2 days before rash onset until all lesions have crusted/dried
• An 8-year-old falls in the classic age group; household secondary cases tend to have more lesions than the index case
• Immunity after wild-type infection is generally lifelong

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Clinical Presentation

• Low-grade fever, malaise, headache, anorexia

• Starts on the back of the head/ears, then spreads centrifugally to face, trunk, proximal extremities
• Mucous membrane involvement is common
• 250-500 lesions in an unvaccinated child, varying in number from 10 to several hundred
• Key feature: lesions appear in successive crops - simultaneously showing macules, papules, vesicles, pustules, and crusts at different stages

1. Erythematous macule/papule
2. Fluid-filled vesicle ("dewdrop on a rose petal")
3. Vesicle becomes turbid/cloudy in 1-2 days
4. Crust forms

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Diagnosis

• Primarily clinical - the characteristic rash at multiple stages is usually diagnostic
• Lab confirmation (if needed - atypical/severe cases):
  • PCR - most sensitive; from vesicular swabs, scrapings, or CSF
  • Direct Fluorescent Antibody (DFA) - rapid antigen detection from lesion scraping
  • Multinucleated giant cells on Tzanck smear (not VZV-specific)

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Complications in Children

• Immunocompromised (T-cell defects, HIV, malignancy)
• High-dose systemic corticosteroids (>2 mg/kg/day prednisone)
• Chronic skin or pulmonary disorders
• Long-term salicylate therapy
• Infants and adolescents

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Treatment

For a healthy 8-year-old (immunocompetent)

• Daily bathing and meticulous skin care; keep fingernails short to reduce scratching
• Tepid water baths and wet compresses for pruritus (better than drying lotions)
• Oral antihistamines (e.g., diphenhydramine) for itch
• Acetaminophen/paracetamol for fever - NOT aspirin or salicylates (Reye syndrome risk)
• NSAIDs (ibuprofen) - use cautiously; some guidelines advise against ibuprofen due to risk of invasive Group A Streptococcal infection

• Acyclovir may be considered in children <12 years if started within 24 hours of rash onset (20 mg/kg orally every 6 hours, max 800 mg/dose, for 5 days), but benefit is modest
• Routine use is not AAP-recommended for otherwise healthy children under 12
• The AAP recommends acyclovir for children >12 years, those with chronic skin/pulmonary disorders, on long-term salicylates, or on corticosteroids

• Treat with a first-generation cephalosporin if present

For immunocompromised children or severe disease

• IV acyclovir: 10 mg/kg every 8 hours for 7 days
• Reduces visceral dissemination; indicated for immunocompromised, varicella pneumonia, or encephalitis

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Isolation and Infection Control

• Isolate the child from school/daycare until all lesions are crusted (typically 5-7 days after rash onset)
• In healthcare settings, strict airborne + contact precautions are required
• Particularly important if immunocompromised contacts are present

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Prevention

• 2-dose schedule is 98% effective against varicella; 100% effective against severe disease
• If unvaccinated and exposed, post-exposure vaccination within 3-5 days can prevent or attenuate illness
• Varicella-Zoster Immune Globulin (VZIG) within 10 days for high-risk susceptible contacts (immunocompromised, neonates, pregnant seronegative women)

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Summary Table for an 8-Year-Old

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