What is the management of chicken pox (varicella) in pediatric patients?

Management of Chickenpox (Varicella) in Pediatric Patients

Primary Treatment Approach

For otherwise healthy children with uncomplicated chickenpox, supportive care alone is the recommended management, as oral acyclovir provides only marginal benefit (reducing fever by approximately 1 day and symptoms by 15-30%) and is not routinely indicated. 1, 2, 3

Supportive Care Measures

• Symptomatic relief with lukewarm baths containing colloidal oatmeal to reduce itching 2
• Fever management with acetaminophen (avoid aspirin due to Reye syndrome risk) 4
• Strict avoidance of ibuprofen as it has been associated with increased risk of severe bacterial superinfections, particularly invasive Group A streptococcal infections 5
• Isolation until all lesions have crusted over (typically 5-7 days after rash onset) to prevent transmission 2

When to Consider Antiviral Therapy

Oral acyclovir (20 mg/kg four times daily for 5 days, maximum 800 mg per dose) should be initiated within 24 hours of rash onset for specific high-risk groups: 6, 3

• Adolescents ≥13 years of age (higher risk of severe disease) 3
• Children with chronic cutaneous or pulmonary disorders 3
• Children on long-term salicylate therapy 3
• Immunocompromised patients (though intravenous acyclovir is preferred for severe immunosuppression) 6, 1

Critical Timing Consideration

Acyclovir loses therapeutic effectiveness if initiated beyond 24 hours after rash onset 7, 3. The drug reduces maximum lesion count (294 vs 347 lesions), accelerates healing, and limits constitutional symptoms to 3-4 days versus >4 days in 20% of untreated patients 7.

Special Populations

HIV-Infected Children

• Varicella vaccine should be considered for asymptomatic HIV-infected children in CDC class 1 with CD4 T-lymphocyte percentage ≥15% 1
• Use two doses of monovalent varicella vaccine with 3-month interval 1
• Post-exposure prophylaxis with VZIG (varicella-zoster immune globulin) within 96 hours for susceptible HIV-infected children 1

Children on Immunosuppressive Therapy

• Varicella vaccine is contraindicated in children receiving high-dose systemic corticosteroids (≥2 mg/kg/day prednisone or ≥20 mg/day for ≥14 days) 1
• Wait at least 1 month after discontinuing corticosteroids before vaccination 1
• VZV vaccination should be strongly considered for varicella-naïve patients on methotrexate monotherapy 1
• Can be considered for patients on TNF inhibitors, anti-IL1, anti-IL6, or low-dose glucocorticosteroids, though with lower evidence grade 1

Leukemia Patients

• Routine immunization is NOT recommended for children with acute lymphocytic leukemia due to variability in chemotherapy regimens and decreased community varicella incidence 1
• Immunization should only occur in remission, with expert guidance, and with antiviral therapy available for potential complications 1

Post-Exposure Prophylaxis for Contacts

Vaccination Strategy

• Varicella vaccine within 3 days of exposure is >90% effective at preventing disease 4
• Vaccine within 5 days is 70% effective at preventing disease and 100% effective at modifying severe disease 4

Passive Immunoprophylaxis

VariZIG (varicella-zoster immune globulin) should be administered within 96 hours for: 1, 4

• Immunocompromised children without varicella immunity
• Susceptible HIV-infected children
• Pregnant women who are VZV-susceptible
• High-risk exposed individuals without evidence of immunity

Alternative: Acyclovir Prophylaxis

Recent data shows acyclovir for post-exposure prophylaxis is associated with higher rates of subsequent varicella disease (15.4%) compared to VariZIG (3.4%) 8. Therefore, VariZIG remains the preferred agent when available for high-risk exposures.

Monitoring for Complications

The most critical complications requiring immediate recognition are: 4

• Bacterial superinfections (most common, especially Group A streptococcus)
• Pneumonia (leading cause of varicella-related death)
• Central nervous system complications including encephalitis and cerebellar ataxia
• Necrotising fasciitis

High-Risk Age Groups

• Infants <1 year are 6 times more likely to require hospitalization than children aged 5-9 years 4
• Early surgical consultation is essential for suspected invasive bacterial infections 4

Common Pitfalls to Avoid

• Do not delay acyclovir beyond 24 hours if treatment is indicated—it becomes ineffective 7, 3
• Never use aspirin or ibuprofen for fever management due to Reye syndrome and bacterial superinfection risks 4, 5
• Do not rely solely on patient/parent history of prior chickenpox in the vaccine era—only 75% of reported cases in unvaccinated children aged 1-4 years are actually seropositive 1
• Do not vaccinate children on high-dose corticosteroids or with severe immunosuppression 1
• Do not assume acyclovir prevents complications—it has not been shown to reduce rates of acute complications in otherwise healthy children 3

Renal Dosing Adjustments

For children with renal impairment receiving acyclovir: 6

• Creatinine clearance 10-25 mL/min/1.73m²: 800 mg every 8 hours
• Creatinine clearance 0-10 mL/min/1.73m²: 800 mg every 12 hours
• Hemodialysis patients: Administer additional dose after each dialysis session

Evidence of Prior Immunity

Documentation of immunity includes: 9

• Laboratory confirmation of immunity or disease
• History of varicella disease verified by a healthcare professional
• Laboratory evidence of immunity via serology

Children with documented prior chickenpox do not require vaccination 9.