Management of Chickenpox in Adults
Adults with chickenpox should be treated with oral acyclovir 800 mg four times daily for 5 days, initiated within 24 hours of rash onset to maximize clinical benefit. 1, 2
Immediate Treatment Algorithm
Immunocompetent Adults
- Start oral acyclovir immediately if presenting within 24 hours of rash onset: 800 mg orally 4 times daily for 5 days 1, 2
- Treatment initiated within the first 24 hours provides the greatest reduction in fever duration, constitutional symptoms, and time to cutaneous healing 3, 4
- Five days of therapy is sufficient—extending to 7 days provides no additional benefit 4
- If presenting between 24-48 hours after rash onset, still initiate acyclovir as some clinical benefit persists, though less pronounced than early treatment 4
Immunocompromised Adults
- Administer intravenous acyclovir 10 mg/kg every 8 hours immediately upon recognition of chickenpox 1, 3
- This population faces potentially fatal outcomes without prompt IV therapy 3, 5
- Do not use oral formulations in immunocompromised patients 2
Renal Dosing Adjustments
For patients with renal impairment receiving the standard 800 mg dose 2:
- Creatinine clearance >25 mL/min: 800 mg every 4 hours (5 times daily)
- 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 an additional dose after each dialysis session 2
Post-Exposure Prophylaxis
For susceptible adults (no history of chickenpox or seronegative for VZV) exposed to active chickenpox 6, 1:
- Administer varicella-zoster immune globulin (VZIG) within 96 hours of exposure as first-line prophylaxis 6, 1
- If VZIG is unavailable, consider a 7-day course of oral acyclovir started 7-10 days after exposure 1
Critical Clinical Pearls
Timing is everything: The efficacy of acyclovir correlates directly with how quickly treatment begins after rash onset 3, 4. Each day of delay reduces clinical benefit, with the most dramatic improvements seen when therapy starts on day 1 of rash 4.
Age matters significantly: Adults and adolescents experience more severe chickenpox than children, with higher rates of complications and mortality 3, 7. This makes antiviral treatment particularly important in this population 3.
Viral resistance is not a concern: Studies demonstrate that viruses shed during acyclovir therapy retain normal susceptibility and thymidine kinase function, so resistance should not deter appropriate treatment 4.
Common Pitfalls to Avoid
- Do not delay treatment waiting for laboratory confirmation—chickenpox is a clinical diagnosis and treatment should begin immediately 1, 7
- Do not withhold treatment if the patient presents slightly after 24 hours; some benefit persists through 48 hours 4
- Do not use oral acyclovir in immunocompromised patients—they require IV formulation 1, 3
- Do not continue chronic suppressive therapy after lesions resolve—this is unnecessary for chickenpox 6