Treatment of Chickenpox (Varicella)
For otherwise healthy children and adults with chickenpox, oral acyclovir 20 mg/kg (maximum 800 mg) four times daily for 5 days is the first-line treatment when initiated within 24 hours of rash onset, though symptomatic therapy alone is adequate for most immunocompetent patients. 1
Treatment Approach by Patient Population
Immunocompetent Children (2 years and older)
- Oral acyclovir 20 mg/kg per dose (maximum 800 mg) four times daily for 5 days is FDA-approved for chickenpox treatment 1
- Children over 40 kg should receive the adult dose of 800 mg four times daily 1
- Treatment should be initiated within 24 hours of rash onset for maximum benefit 1
- Symptomatic therapy alone is usually adequate for healthy children with uncomplicated disease 2
Immunocompetent Adults and Adolescents
- Oral acyclovir 800 mg four times daily for 5 days when treatment is indicated 1
- Adults are at higher risk for severe disease compared to children and benefit more from antiviral therapy 3, 4
- Early initiation (within 24 hours) is critical as treatment started later has minimal effect 1
Immunocompromised Patients
- Intravenous acyclovir 10 mg/kg every 8 hours is indicated for varicella in immunocompromised patients 1, 4
- IV acyclovir causes more rapid resolution and fewer complications in this population 4
- Adequate hydration must be maintained and renal function monitored 1, 4
Symptomatic Management
General Supportive Care
- Maintain adequate hydration in all patients 1
- Paracetamol (acetaminophen) is the preferred antipyretic for fever control 5
- Avoid NSAIDs (ibuprofen, aspirin) due to increased risk of severe bacterial skin infections 5
Antibiotic Therapy
- Antibiotics are indicated only when bacterial superinfection occurs 2
- Co-amoxiclav was most frequently used in adults, while ceftriaxone was preferred in children with bacterial complications 2
Post-Exposure Prophylaxis
High-Risk Exposed Individuals
- Varicella-zoster immune globulin (VZIG) should be administered within 96 hours of exposure to susceptible immunocompromised patients, pregnant women, or neonates 6
- For immunocompromised patients on immunosuppressive therapy (including IBD patients), aciclovir prophylaxis is recommended as a 7-day course starting 7 days after exposure when VZIG is unavailable 6
Vaccination Considerations
- Live varicella vaccine is contraindicated in patients receiving immunosuppressive therapy 6
- Immunosuppressive therapies include corticosteroids ≥20 mg/day prednisolone for ≥2 weeks, purine analogues, methotrexate, and biologic therapies 6
Dosage Adjustments for Renal Impairment
Dose modification is essential in renal dysfunction 1:
- Creatinine clearance 10-25 mL/min: 800 mg every 8 hours (for standard 800 mg q4h regimen)
- Creatinine clearance 0-10 mL/min: 800 mg every 12 hours
- Hemodialysis patients: Administer additional dose after each dialysis session 1
Critical Timing Considerations
- Treatment efficacy is maximized when started within 24 hours of rash onset 1
- There is no information on efficacy when treatment begins more than 24 hours after symptom onset 1
- Clinical trials demonstrated that acyclovir shortened time to healing, reduced maximum lesion count, and decreased systemic symptoms when given early 1, 7
Common Pitfalls to Avoid
- Do not use NSAIDs for fever control - stick with paracetamol to avoid increased risk of necrotizing fasciitis and severe bacterial skin infections 5
- Do not delay treatment in high-risk patients (adults, adolescents, immunocompromised) waiting for "full-blown" disease 3, 4
- Do not administer live varicella vaccine to immunosuppressed patients or within 3 months of stopping immunosuppressive therapy 6
- Do not forget to adjust acyclovir dosing for renal impairment to prevent CNS toxicity 1
Special Populations
Pregnancy
- VZIG is not contraindicated and should be given to VZV-susceptible pregnant women after exposure 6
- Acyclovir is Pregnancy Category B; use only if potential benefit justifies potential risk 1