Treatment of Chickenpox in Adolescents
Adolescents (≥13 years) with chickenpox should receive oral acyclovir 800 mg four times daily for 5 days, initiated within 24 hours of rash onset for optimal benefit. 1, 2, 3
Treatment Rationale and Timing
Adolescents are at significantly higher risk for severe varicella compared to younger children, making antiviral therapy particularly important in this age group. 3 The severity of chickenpox increases substantially with age, and secondary household cases tend to be more severe than primary cases. 4
Critical timing considerations:
- Acyclovir must be started within 24 hours of rash onset to achieve therapeutic benefit 1, 5
- Treatment initiated beyond 24 hours results in loss of therapeutic effect 3
- Do not delay treatment waiting for laboratory confirmation—diagnosis is clinical and time is critical 1
Specific Dosing Regimen
Standard oral acyclovir dosing for adolescents: 2
- 800 mg orally four times daily for 5 days
- Alternative: 20 mg/kg per dose (maximum 800 mg) four times daily if weight-based dosing preferred 6, 2
Valacyclovir is an acceptable alternative with simpler dosing:
- 20 mg/kg three times daily (maximum 1 gram three times daily) for 5 days 7
Expected Clinical Benefits
When initiated within 24 hours, acyclovir provides: 1, 5
- Reduced number of days new lesions appear
- Decreased fever duration (limited to 3-4 days vs >4 days in 20% of untreated patients)
- Lessened severity of cutaneous and systemic symptoms
- Accelerated progression to crusted and healed stages
- Reduced varicella-associated morbidity and mortality
Important limitation: Acyclovir does not reduce transmission to household contacts or duration of school absence, so isolation precautions remain essential. 8, 9
Special Circumstances Requiring Treatment
Beyond routine adolescent treatment, acyclovir is specifically recommended for: 1, 3
- Persons with chronic cutaneous or pulmonary disorders
- Those on long-term salicylate therapy
- Those receiving corticosteroids
- Secondary or tertiary household cases (typically more severe)
Immunocompromised Patients
If the adolescent is immunocompromised (HIV-infected, on chemotherapy, etc.), switch to intravenous acyclovir immediately: 6, 4
- 10 mg/kg IV every 8 hours for 7-10 days
- Some experts recommend 500 mg/m² IV every 8 hours for patients >1 year 6
- Continue until no new lesions for 48 hours
- This is potentially life-saving as varicella in immunocompromised individuals can be fatal 4
Safety and Long-term Considerations
Acyclovir is well-tolerated with no significant adverse effects demonstrated in otherwise healthy patients. 5, 3 Importantly:
- Does not interfere with antibody development or immune response 6, 8
- Does not alter future herpes zoster risk—antibody titers after treatment are comparable to untreated infection 8
- Viral latency establishment is unaffected, as acyclovir treats acute infection but does not prevent VZV from establishing latency in dorsal root ganglia 8
Common Pitfalls to Avoid
- Do not wait beyond 24 hours to initiate therapy—the window is narrow and therapeutic benefit is lost with delay 1, 3
- Do not withhold treatment in typical presentations while awaiting laboratory confirmation 1
- Do not assume acyclovir will prevent complications in otherwise healthy adolescents—no demonstrable effect on complication rates has been shown, though the studies may have been underpowered for rare events 9, 5
- Do not forget isolation precautions—patient remains contagious until all lesions are crusted 10