Varicella Treatment
For healthy children with uncomplicated chickenpox, symptomatic treatment alone is appropriate; however, adults, adolescents ≥13 years, immunocompromised patients, pregnant women, and neonates require antiviral therapy with acyclovir or varicella-zoster immune globulin (VZIG) for post-exposure prophylaxis in high-risk susceptible individuals. 1, 2
Treatment by Population
Healthy Children (12 months to 12 years)
- Symptomatic treatment only is recommended for immunocompetent children with uncomplicated varicella 1, 2
- The disease is typically self-limited, lasting 4–5 days with 250–500 vesicular lesions 1, 2
- If antiviral therapy is indicated (e.g., household contacts at high risk, early presentation within 24 hours), use oral acyclovir 20 mg/kg per dose four times daily (maximum 800 mg per dose) for 5 days 3
- Treatment must be initiated within 24 hours of rash onset for optimal efficacy 3
Common pitfall: Do not use aspirin or salicylates in children with varicella due to the risk of Reye syndrome; avoid for 6 weeks following vaccination as well 2, 4
Adolescents ≥13 Years and Adults
- Oral acyclovir 800 mg five times daily for 5 days is the standard treatment 3
- Adolescents and adults have 13 times higher hospitalization risk and 25 times higher case-fatality rate compared to young children 2
- Initiate therapy at the earliest sign of illness, ideally within 24 hours of rash onset 1, 3
- Adults are at significantly higher risk for complications including pneumonia and disseminated disease 1, 2
Immunocompromised Patients
- Intravenous acyclovir is indicated for varicella in immunocompromised patients 3, 5
- Dosing: 10 mg/kg IV every 8 hours (or 500 mg/m² every 8 hours) 5, 6
- Continue treatment for at least 7–10 days and until all lesions have completely crusted 7
- Consider temporary reduction or discontinuation of immunosuppressive medications if clinically feasible 7, 2
- Untreated immunocompromised children have a 28% incidence of pneumonitis and 7% mortality rate 6
Critical monitoring: Maintain adequate hydration and urine flow; monitor renal function at baseline and weekly; assess mental status for CNS toxicity 5
Pregnant Women
- Varicella-zoster immune globulin (VZIG) within 96 hours of exposure is recommended for VZV-susceptible pregnant women 8, 2
- VZIG provides maximum benefit when administered as soon as possible, but remains effective up to 96 hours post-exposure 8, 2
- Maternal varicella during the first 20 weeks of gestation carries approximately 1.1% risk of congenital varicella syndrome 2
- If VZIG is unavailable or >96 hours have passed, consider a 7-day course of oral acyclovir beginning 7–10 days after exposure 7
Important: Varicella vaccine is contraindicated in pregnancy; pregnancy should be avoided for 3 months following vaccination 4
Neonates
- VZIG is indicated for exposed neonates <28 weeks gestation or <1,000 g within 96 hours of exposure 2
- Neonates exhibit higher case-fatality rates compared to older pediatric age groups 2
- Infants <1 year old are 6 times more likely to require hospitalization than children aged 5–9 years 2
Post-Exposure Prophylaxis
Varicella Vaccine (for susceptible individuals without contraindications)
- Administer within 3–5 days of exposure to prevent or modify disease 8, 2
- Recommended for susceptible household contacts, healthcare workers, and other high-risk individuals 2
- Protective efficacy after household exposure is approximately 65% in adults; breakthrough illness is invariably mild 9
Dosing schedule:
- Children 12 months to 12 years: Two doses with minimum 3-month interval 8
- Adolescents ≥13 years and adults: Two doses with minimum 4-week interval 8
Varicella-Zoster Immune Globulin (VZIG)
- Administer within 96 hours of exposure to high-risk susceptible individuals 8, 2
- Indications: Pregnant women without immunity, immunocompromised patients, neonates <28 weeks gestation or <1,000 g 8, 2
- Dosing: 5 vials (1.25 mL each) intramuscularly 8
- VZIG may prolong the incubation period by one week, extending the monitoring period from 21 to 28 days 8
Infection Control Measures
- Patients are contagious from 1–2 days before rash onset until all lesions have completely crusted (typically 4–7 days after rash onset) 8, 2
- Implement both airborne and contact precautions for hospitalized patients 8, 1
- Isolate from susceptible individuals until complete crusting of all lesions 1, 2
- Only healthcare personnel with evidence of immunity should care for patients with varicella 8
Special Considerations
Renal Impairment
Acyclovir dosing must be adjusted based on creatinine clearance 3:
| Creatinine Clearance | Dose | Interval |
|---|---|---|
| >10 mL/min | 800 mg | Every 4 hours, 5× daily |
| 10–25 mL/min | 800 mg | Every 8 hours |
| 0–10 mL/min | 800 mg | Every 12 hours |
- For hemodialysis patients, administer an additional dose after each dialysis session 3
HIV-Infected Patients
- VZIG should be administered within 96 hours after close contact for VZV-susceptible HIV-infected individuals 8
- Higher oral acyclovir doses may be needed (up to 800 mg 5–6 times daily) 7
- Consider IV acyclovir for severe disease 7
Key Clinical Pearls
- Never use aspirin in patients with varicella or for 6 weeks after vaccination due to Reye syndrome risk 2, 4
- The key criterion for ending isolation is complete crusting of ALL lesions, not a specific number of days 2
- Antiviral therapy is most effective when initiated within 24 hours of rash onset 1, 3
- Birth before 1980 is not considered evidence of immunity for pregnant women due to potential severe consequences 8
- Topical acyclovir is substantially less effective than systemic therapy and is not recommended 7, 5