What is the recommended treatment for Varicella zoster (chickenpox/shingles)?

Treatment of Varicella Zoster Virus Infections

For immunocompetent adults with herpes zoster (shingles), oral valacyclovir 1000 mg three times daily for 7 days is the first-line treatment, ideally initiated within 72 hours of rash onset. 1, 2, 3

Treatment Algorithm by Clinical Presentation

Uncomplicated Herpes Zoster (Shingles) in Immunocompetent Patients

First-line options:

• Valacyclovir 1000 mg orally three times daily for 7 days 1, 2, 3
• Acyclovir 800 mg orally five times daily for 7-10 days 3
• Famciclovir 500 mg orally three times daily for 7 days 1, 2

Key treatment principles:

• Initiate therapy within 72 hours of rash onset for optimal efficacy, though benefit may still occur with later initiation 1, 4
• Continue treatment until all lesions have completely scabbed over, not just for an arbitrary 7-day period 1, 2
• Valacyclovir demonstrates superior efficacy compared to acyclovir in reducing duration of zoster-associated pain and postherpetic neuralgia 5
• The twice-daily valacyclovir 1.5 g regimen shows equivalent efficacy to three-times-daily dosing and may improve compliance 6

Disseminated or Severe Herpes Zoster

For multi-dermatomal involvement, visceral dissemination, or immunocompromised patients:

• Intravenous acyclovir 5-10 mg/kg every 8 hours 1, 2
• Continue IV therapy for minimum 7-10 days and until clinical resolution is attained 1, 2
• Switch to oral therapy (valacyclovir or acyclovir) once clinical improvement occurs 2
• Temporarily reduce or discontinue immunosuppressive medications if applicable 1, 2

Specific indications for IV therapy:

• Herpes zoster ophthalmicus with severe ocular involvement 1
• CNS complications (encephalitis, meningitis) 1
• Disseminated cutaneous disease (>2 dermatomes) 2
• Visceral organ involvement 7, 1
• Severely immunocompromised hosts (HIV with CD4 <200, active chemotherapy, transplant recipients) 8, 2

Primary Varicella (Chickenpox)

For immunocompetent children and adults:

• Children ≥2 years and ≤40 kg: Acyclovir 20 mg/kg orally four times daily for 5 days (maximum 800 mg per dose) 3
• Adults and children >40 kg: Acyclovir 800 mg orally four times daily for 5 days 3
• Initiate treatment within 24 hours of rash onset for maximum benefit 3

For immunocompromised patients with varicella:

• Intravenous acyclovir is indicated 3
• Discontinue immunosuppressive therapy in severe cases 2

Special Populations and Considerations

HIV-Infected Patients

Treatment approach:

• Higher oral acyclovir doses may be needed: 800 mg 5-6 times daily 1
• Consider IV acyclovir for severe disease regardless of CD4 count 1
• Long-term acyclovir prophylaxis (400 mg 2-3 times daily) may be beneficial for recurrent episodes 1
• Monitor for acyclovir resistance if lesions persist despite treatment 1

Renal Impairment

Dose adjustments for acyclovir 800 mg regimen:

• CrCl >25 mL/min: 800 mg every 4 hours, 5 times daily 3
• CrCl 10-25 mL/min: 800 mg every 8 hours 3
• CrCl 0-10 mL/min: 800 mg every 12 hours 3
• Hemodialysis: Administer additional dose after each dialysis session 3

For famciclovir:

• CrCl ≥60 mL/min: 500 mg every 8 hours 1
• Adjust dosing based on creatinine clearance for lower values 1

Pregnant Women

Post-exposure prophylaxis:

• VZV-susceptible pregnant women should receive varicella zoster immune globulin (VZIG) within 96 hours after exposure 7
• If VZIG unavailable or >96 hours post-exposure: oral acyclovir 7-day course beginning 7-10 days after exposure 1, 2

Active infection:

• Oral acyclovir can be used; no pattern of adverse pregnancy outcomes reported 7
• Famciclovir is category B and may be considered for severe cases 2

Immunocompromised Patients (Non-HIV)

Patients on immunosuppressive therapy (IBD, transplant, chemotherapy):

• All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing from rash onset 2
• Consider IV acyclovir for any facial involvement or severe disease 1, 2
• Temporarily discontinue or reduce immunosuppressive therapy in severe or disseminated cases 7, 2
• Restart immunosuppression only after antiviral therapy initiated and skin vesicles have resolved 2

Prophylaxis for high-risk patients:

• Acyclovir or valacyclovir prophylaxis recommended for patients receiving proteasome inhibitor-based therapies (e.g., bortezomib) 1
• Daily acyclovir 400 mg effective in myeloma patients 1

Acyclovir-Resistant Cases

Management approach:

• Suspect resistance if lesions persist or worsen despite adequate antiviral therapy 1, 8
• Foscarnet 40 mg/kg IV every 8 hours is the treatment of choice 7, 2
• Acyclovir-resistant VZV isolates are routinely resistant to ganciclovir as well 7
• Monitor renal function and electrolytes closely (hypocalcemia, hypophosphatemia, hypomagnesemia, hypokalemia) 2

Post-Exposure Prophylaxis

For VZV-susceptible individuals (no history of chickenpox/shingles or seronegative):

• VZIG as soon as possible but within 96 hours after close contact 7, 1, 2
• If VZIG unavailable or >96 hours elapsed: oral acyclovir for 7 days beginning 7-10 days after exposure 1, 2

High-risk populations requiring prophylaxis:

• HIV-infected patients without VZV immunity 7
• Pregnant women 7
• Immunocompromised patients on active therapy 7

Common Pitfalls and Caveats

Timing considerations:

• While 72 hours is the traditional cutoff, treatment initiated later may still provide benefit for pain reduction 1, 5
• Continue treatment until all lesions have scabbed, not just for 7 days if healing is incomplete 1, 2

Dosing errors to avoid:

• Acyclovir 400 mg three times daily is inadequate for herpes zoster—this dose is only appropriate for HSV suppression 1
• The herpes zoster dose is 800 mg five times daily, not the lower HSV doses 3

Monitoring requirements:

• Monitor renal function closely during IV acyclovir therapy with dose adjustments as needed 1
• Assess for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients receiving high-dose therapy 1

Topical therapy:

• Topical antiviral therapy is substantially less effective than systemic therapy and is not recommended 1

Prevention: Vaccination

Recombinant zoster vaccine (Shingrix):

• Recommended for all adults ≥50 years regardless of prior herpes zoster episodes 1, 2
• Should be administered before initiating immunosuppressive therapies when possible 1
• Preferred over live zoster vaccine for prevention of herpes zoster and related complications 2