What are the treatment guidelines for chickenpox?

Chickenpox Treatment Guidelines

General Approach

For otherwise healthy children with uncomplicated chickenpox, routine antiviral therapy is not recommended, as the marginal therapeutic benefit does not justify universal treatment. 1, 2 However, symptomatic care remains the cornerstone for immunocompetent patients without complications. 3

Indications for Antiviral Treatment

Acyclovir therapy should be initiated for specific high-risk populations:

High-Risk Groups Requiring Treatment

• Adolescents and adults ≥13 years of age 1, 2
• Immunocompromised patients (require intravenous acyclovir) 1
• Children with chronic cutaneous or pulmonary disorders 1, 2
• Patients receiving long-term salicylate therapy 1, 2
• Patients on corticosteroid therapy 1

Timing is Critical

• Treatment must be initiated within 24 hours of rash onset for maximum benefit 4, 5, 6, 2
• Starting therapy after 24 hours results in progressively diminished therapeutic effect 5
• Treatment initiated on day 2 of rash shows some benefit but is significantly less effective than day 1 initiation 5

Dosing Recommendations

Oral Acyclovir (Immunocompetent Patients)

Children <40 kg:

• 20 mg/kg per dose (maximum 800 mg) orally 4 times daily for 5 days 1, 4

Adults and children >40 kg:

• 800 mg orally 4 times daily for 5 days 1, 4

Duration: Five days of therapy is sufficient; a 7-day course provides no additional benefit 5

Intravenous Acyclovir (Severe Disease/Immunocompromised)

• 10 mg/kg IV every 8 hours for 7-10 days 7, 1
• This route is mandatory for immunocompromised patients and those with severe disease 1, 4

Post-Exposure Prophylaxis

For Susceptible Immunocompromised Patients

First-line:

• Varicella zoster immune globulin (VZIG) as soon as possible, up to 10 days after exposure 7, 1
• Most effective when given within 96 hours 7, 1

If VZIG unavailable:

• Oral acyclovir 10 mg/kg four times daily for 7 days, starting 7-10 days after exposure 7, 1

Special Populations Requiring VZIG

• Pregnant women without evidence of immunity 7
• Neonates born to mothers with varicella 5 days before to 2 days after delivery 7
• Premature infants <28 weeks gestation or <1,000 g regardless of maternal immunity 7

Expected Therapeutic Benefits

When acyclovir is initiated within 24 hours of rash onset in immunocompetent patients:

• Reduction in total lesion count (294 vs 347 lesions; 21% vs 38% with >500 lesions) 6
• Cessation of new lesion formation by day 3 in >95% of treated patients 6
• Fever and constitutional symptoms limited to 3-4 days (vs >4 days in 20% of untreated) 6
• Accelerated progression to crusting and healing 5, 6
• Reduced itching and fewer residual lesions at 28 days 6

Infection Control

• Isolate patients until all lesions have crusted over 1
• Healthcare workers without immunity exposed to VZV should be furloughed days 10-21 after exposure 7, 1

Common Pitfalls to Avoid

• Do not delay treatment beyond 24 hours - therapeutic efficacy is significantly reduced 5, 2
• Do not use acyclovir routinely in healthy children - marginal benefit does not justify universal use 2
• Do not rely on antibody titers in patients with nephrotic-range proteinuria or receiving IVIG - these are unreliable 7
• Do not administer live varicella vaccine to immunocompromised patients - risk of disseminated infection 7, 1
• Acyclovir does not reduce acute complications in otherwise healthy children 2
• Viral resistance does not develop during short-course therapy 5

Vaccination Considerations

• Susceptible household contacts of immunocompromised patients should be vaccinated to prevent transmission 7, 1
• HIV-infected children who are asymptomatic and not immunosuppressed may receive varicella vaccine at 12-15 months 7
• Delay varicella vaccination 5 months after VZIG administration 7