What is the recommended management for varicella infection?

Management of Varicella Infection

For otherwise healthy children with varicella, supportive care alone is recommended, while oral acyclovir 800 mg four times daily for 5 days should be initiated within 24 hours of rash onset for persons ≥13 years, immunocompromised patients requiring intravenous therapy, and pregnant women with complications. 1

Risk-Stratified Treatment Algorithm

Healthy Children (<13 years)

• Supportive care only is recommended for otherwise healthy children with uncomplicated varicella 1, 2
• Oral acyclovir is not routinely indicated because it provides only marginal benefit (1-day reduction in fever, 15-30% reduction in symptom severity) without reducing complications, pruritus, transmission, or school absence 2
• Consider oral acyclovir 20 mg/kg four times daily for 5 days (maximum 800 mg per dose) only for children with chronic cutaneous disorders (e.g., eczema), chronic pulmonary disease, or those receiving long-term salicylate therapy, if initiated within 24 hours of rash onset 1, 3

Adolescents and Adults (≥13 years)

• Oral acyclovir 800 mg four times daily for 5 days is recommended if treatment begins within 24 hours of rash onset 1, 3
• This population experiences more severe disease than children, justifying antiviral therapy 4, 5
• Critical pitfall: Acyclovir loses efficacy when initiated >24 hours after rash onset 1

Immunocompromised Patients

• Intravenous acyclovir 10 mg/kg every 8 hours for 7-10 days should be initiated immediately upon diagnosis, regardless of timing 1, 4
• This population faces significant risk of dissemination, visceral complications, and death without prompt antiviral therapy 4, 6
• Intravenous acyclovir has been demonstrated to reduce varicella-associated morbidity and mortality when administered within 24 hours of rash onset 4
• Treatment should continue for a minimum of 7-10 days 1

Pregnant Women

• For uncomplicated varicella: Routine acyclovir is not recommended 7
• For increased risk of moderate-to-severe disease: Oral acyclovir should be considered if initiated within 24 hours of rash onset 7, 4
• For serious complications (e.g., pneumonia): Intravenous acyclovir is indicated 1
• Safety profile: Acyclovir is FDA Category B in pregnancy, with a registry of 596 first-trimester exposures showing no increased birth defect rates compared to the general population 7, 4

Post-Exposure Prophylaxis

Vaccination Strategy

• Varicella vaccine within 3 days of exposure is >90% effective in preventing disease for susceptible individuals without contraindications 1
• This is the preferred method of post-exposure prophylaxis for otherwise healthy individuals 1

Varicella-Zoster Immune Globulin (VZIG)

• Administer within 96 hours of exposure for high-risk individuals with contraindications to vaccination 1, 4

• Specific indications for VZIG include:

  • Immunocompromised patients without evidence of immunity after direct exposure 4
  • Neonates whose mothers developed varicella from 5 days before to 2 days after delivery 4
  • Pregnant women without immunity to VZV (reduces infection rate from >70% to 30%) 4, 7
  • Premature infants born at <28 weeks gestation or weighing <1,000 g at birth, regardless of maternal immunity 4
  • Premature infants born at ≥28 weeks whose mothers lack evidence of immunity 4

• Critical considerations: VZIG reduces complications and fatal outcomes in neonates but does not substantially reduce attack rates (62% with VZIG vs. similar rates without) 4

Infection Control Measures

• Isolate patients until all lesions are crusted, typically 5-7 days after rash onset 1
• Airborne and contact precautions are required in healthcare settings 1
• Household contacts experience approximately 85% attack rate (range 65-100%), while close contact outside the household carries approximately 20% of household risk 4

Critical Pitfalls to Avoid

• Do not initiate acyclovir >24 hours after rash onset in otherwise healthy patients, as efficacy is lost 1, 4
• Do not use acyclovir for prophylaxis in otherwise healthy individuals after exposure—vaccination is the method of choice 1
• Do not delay VZIG beyond 96 hours for high-risk exposed individuals, as effectiveness diminishes significantly 7
• Do not withhold intravenous acyclovir from immunocompromised patients based on timing—treat immediately regardless of when rash appeared 1
• Ensure adequate hydration and monitor renal function when using high-dose acyclovir (800 mg five times daily or intravenous dosing) 8