Treatment of Varicella (Chickenpox)
For immunocompromised patients with active varicella, intravenous acyclovir should be initiated immediately, while healthy children generally do not require antiviral treatment unless they are at increased risk for moderate to severe disease (age >12 years, chronic pulmonary/cutaneous disorders, or long-term salicylate therapy). 1
Immunocompromised Patients
Intravenous acyclovir is the standard of care and must be started within 24 hours of rash onset to effectively reduce varicella-associated morbidity and mortality in this high-risk population. 1 This includes patients with:
- Primary and acquired immunodeficiency disorders 1
- Neoplastic diseases 1
- Those receiving immunosuppressive treatment 1
- HIV-infected individuals (should be monitored closely and treated at earliest signs) 1
The evidence demonstrates clear benefit when acyclovir is administered within the first 24 hours, with proven reduction in complications and death rates. 1
Healthy Children and Adolescents
Oral Acyclovir Considerations
Oral acyclovir (20 mg/kg per dose, 4 times daily for 5 days; maximum 800 mg per dose) should be considered for otherwise healthy persons at increased risk for moderate to severe varicella, including: 1, 2
- Persons aged >12 years 1
- Those with chronic cutaneous or pulmonary disorders 1
- Patients receiving long-term salicylate therapy 1
- Secondary household cases (some experts recommend) 1
Treatment must be initiated within 24 hours of rash onset to achieve clinical benefit, which includes decreased duration of new lesion formation, reduced fever duration, and decreased severity of symptoms. 1, 2
Routine Healthy Children
For otherwise healthy children without risk factors, the American Academy of Pediatrics does not recommend routine acyclovir administration because the clinical benefit is insufficient to justify routine use, given that complications occur in only 1-2% of cases. 1 The drug does not reduce transmission or decrease school absence duration. 1
Pregnant Women
For pregnant women with serious varicella complications (particularly pneumonia), intravenous acyclovir should be considered despite limited controlled data. 1
- Acyclovir is FDA Category B (animal studies show no teratogenic effects) 1
- A prospective registry of 596 first-trimester exposures showed birth defect rates approximating the general population 1
- Routine oral acyclovir is not recommended for uncomplicated varicella in pregnancy 1
Post-Exposure Prophylaxis (Not Active Treatment)
Vaccination Approach
Post-exposure varicella vaccination within 3 days of exposure is >90% effective in preventing disease and should be the first-line approach for healthy, susceptible individuals. 3 If given within 5 days, it remains 70% effective at preventing disease and 100% effective at modifying severe disease. 3
VariZIG (Varicella-Zoster Immune Globulin)
VariZIG should be administered within 96 hours (ideally as soon as possible) after exposure for high-risk individuals who cannot receive vaccination, including: 1
- Immunocompromised patients without evidence of immunity 1
- Neonates whose mothers developed varicella 5 days before to 2 days after delivery 1
- Pregnant women without immunity 1
- Premature infants 3
Dosing: 125 units/10 kg body weight (maximum 625 units) administered intramuscularly. 1
Critical Caveats
Acyclovir is NOT indicated for prophylactic use in healthy individuals after exposure—vaccination is the method of choice in these situations. 1 No studies support prophylactic acyclovir use in immunocompromised persons; VariZIG is recommended instead. 1
Avoid salicylates during and for 6 weeks after varicella due to Reye syndrome risk. 3
Dose adjustment is required for renal impairment: For creatinine clearance 0-10 mL/min, reduce 800 mg every 4 hours to 800 mg every 12 hours. 2
Monitor for bacterial superinfections (particularly invasive group A streptococcal infections), pneumonia, and neurologic complications, which are the leading causes of varicella-related deaths and require immediate intervention. 3, 4