What is the treatment for chicken pox (varicella)?

Treatment of Chickenpox (Varicella)

For otherwise healthy children with chickenpox, supportive care alone is recommended, while oral acyclovir should be initiated within 24 hours of rash onset for adolescents ≥13 years, immunocompromised patients, pregnant women with complications, and children with chronic cutaneous or pulmonary disorders. 1, 2

Risk-Stratified Treatment Algorithm

Healthy Children (<13 years)

• Supportive care only is recommended for otherwise healthy children without risk factors 1, 3
• Symptomatic treatment includes maintaining adequate hydration, bathing with stringent soaks to prevent secondary bacterial infection, and isolation until all lesions crust 1, 4
• Oral acyclovir is not routinely recommended despite reducing fever by 1 day and symptoms by 15-30%, as it has not been shown to reduce complications, pruritus, or school absence 3

High-Risk Children Requiring Oral Acyclovir

Oral acyclovir (20 mg/kg per dose, maximum 800 mg, 4 times daily for 5 days) should be initiated within 24 hours of rash onset for: 1, 5, 6

• Children with chronic cutaneous disorders (e.g., eczema) 1, 5
• Children with chronic pulmonary disorders 1, 5
• Children receiving long-term salicylate therapy 1, 5
• Children on corticosteroid therapy 1, 5

Adolescents and Adults (≥13 years)

• Oral acyclovir 800 mg 4 times daily for 5 days is recommended if initiated within 24 hours of rash onset 1, 2, 6
• Adults face significantly higher complication rates with case-fatality rates 21.3 per 100,000 versus 0.8 per 100,000 in children aged 1-4 years 2
• Critical pitfall: Acyclovir loses efficacy when initiated >24 hours after rash onset 2

Immunocompromised Patients

• Intravenous acyclovir 10 mg/kg every 8 hours for 7-10 days should be initiated immediately upon diagnosis, ideally within 24 hours of rash onset 1, 2, 5, 6
• This includes HIV-infected patients, transplant recipients, cancer patients on chemotherapy, and those receiving high-dose corticosteroids 2
• IV acyclovir causes more rapid resolution and fewer complications in this population 7

Pregnant Women

• Oral acyclovir is recommended for pregnant women at increased risk for moderate-to-severe disease 2
• Intravenous acyclovir is indicated for pregnant women with serious viral-mediated complications such as pneumonia 2
• Acyclovir is FDA Category B in pregnancy with reassuring safety data showing no increased birth defect rates 2

Post-Exposure Prophylaxis

Vaccination (First-Line)

• Varicella vaccine within 3 days (up to 5 days) of exposure is >90% effective at preventing disease in susceptible immunocompetent individuals 2, 5

Varicella-Zoster Immune Globulin (VZIG)

VZIG should be administered within 96 hours (extended to 10 days per 2013 CDC guidelines) for high-risk individuals who cannot receive vaccine: 8, 2, 5

• Immunocompromised patients without evidence of immunity 8, 5
• Pregnant women without evidence of immunity 8, 5
• Neonates whose mothers developed varicella from 5 days before to 2 days after delivery 8, 5
• Premature infants <28 weeks gestation or <1,000 g regardless of maternal immunity 8, 5
• Premature infants >28 weeks gestation whose mothers lack immunity 8

Dosing: 125 IU/10 kg body weight intramuscularly, maximum 625 IU (five vials); minimum dose 62.5 IU for infants ≤2.0 kg 2

Alternative Post-Exposure Prophylaxis

• If VZIG is unavailable, oral acyclovir 10 mg/kg four times daily for 7 days, starting 7-10 days after exposure may be considered 8, 5

Critical Management Points

Timing of Antiviral Therapy

• Treatment must begin within 24 hours of rash onset to be effective in most populations 2, 6
• Acyclovir is not indicated for prophylactic use in otherwise healthy individuals after exposure—vaccination is preferred 2

Monitoring After VZIG Administration

• Patients receiving VZIG should be observed for 28 days after exposure (VZIG may prolong incubation period by >1 week) 8
• Antiviral therapy should be instituted immediately if signs or symptoms of varicella develop despite VZIG 8, 2
• Varicella vaccination should be delayed 5 months after VZIG administration 8, 5

Infection Control

• Isolate patients until all lesions have crusted, typically 5-7 days after rash onset 1, 2, 5
• Healthcare workers without immunity exposed to VZV should be furloughed for days 10-21 after exposure 1, 5
• Airborne and contact precautions are required in healthcare settings 2

Common Pitfalls to Avoid

• Do not rely on antibody titers in patients with nephrotic-range proteinuria or receiving IVIG, as they are unreliable 5
• Do not administer live varicella vaccine to immunocompromised patients due to risk of disseminated infection 8, 5
• Do not discharge neonates whose mothers developed varicella from 5 days before to 2 days after delivery without VZIG, due to high mortality risk 2
• Do not delay treatment beyond 24 hours in high-risk groups, as therapeutic effect is lost 2, 3

Dosage Adjustments for Renal Impairment

For patients with renal impairment receiving oral acyclovir: 6

• Creatinine clearance 10-25 mL/min: 800 mg every 8 hours
• Creatinine clearance 0-10 mL/min: 800 mg every 12 hours
• Hemodialysis patients: Administer additional dose after each dialysis session 6

Vaccination of Contacts

• Vaccinate susceptible household contacts of immunocompromised patients to prevent transmission 5
• HIV-infected children who are asymptomatic and not immunosuppressed should receive varicella vaccine at 12-15 months 8, 5