What is the recommended treatment for herpes zoster?

Treatment of Herpes Zoster

First-Line Antiviral Therapy

For uncomplicated herpes zoster, initiate oral valacyclovir 1 gram three times daily for 7 days, or alternatively famciclovir 500 mg every 8 hours for 7 days, starting within 72 hours of rash onset and continuing until all lesions have completely scabbed. 1, 2

Standard Oral Antiviral Options

• Valacyclovir 1 gram orally three times daily for 7 days is the preferred first-line agent due to superior bioavailability and convenient dosing 1, 2
• Famciclovir 500 mg orally every 8 hours for 7 days offers equivalent efficacy with better adherence than acyclovir 1, 3
• Acyclovir 800 mg orally five times daily for 7-10 days remains effective but requires more frequent dosing 1, 2

Critical Timing Considerations

• Treatment must be initiated within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia 1, 4, 5
• Treatment within 48 hours is ideal for maximum benefit 1
• Continue treatment until all lesions have completely scabbed, not just for an arbitrary 7-day period—this is the key clinical endpoint 1, 2

Indications for Intravenous Acyclovir

Switch to intravenous acyclovir 5-10 mg/kg every 8 hours for disseminated herpes zoster, immunocompromised patients with severe disease, or any patient with visceral involvement, CNS complications, or ophthalmic disease. 1, 2

Specific IV Indications

• Disseminated herpes zoster (multi-dermatomal or visceral involvement) 1, 2
• Severely immunocompromised patients (active chemotherapy, HIV with low CD4 counts, solid organ transplant recipients) 1
• Complicated facial zoster with suspected CNS involvement 1
• Ophthalmic zoster with severe disease 1
• Failure to respond to oral therapy within 7-10 days 1

IV Dosing and Duration

• Acyclovir 5-10 mg/kg IV every 8 hours until clinical improvement occurs 2
• Continue IV therapy until clinical resolution is attained, then switch to oral therapy to complete the course 2
• Monitor renal function closely during IV therapy with dose adjustments for renal impairment 1

Special Population Considerations

Immunocompromised Patients

• All immunocompromised patients require antiviral treatment regardless of timing beyond the 72-hour window 2
• Consider temporary reduction in immunosuppressive medications for disseminated or invasive disease 1, 2
• Extended treatment duration may be necessary as lesions continue to develop for 7-14 days and heal more slowly 1
• High-dose IV acyclovir remains the treatment of choice for severely compromised hosts 1

Renal Impairment

• Dose adjustments are mandatory to prevent acute renal failure 1, 3
• For famciclovir with CrCl 20-39 mL/min: 500 mg every 24 hours 3
• For famciclovir with CrCl <20 mL/min: 250 mg every 24 hours 3
• For hemodialysis patients: 250 mg following each dialysis 3

Facial and Ophthalmic Involvement

• Facial zoster requires urgent treatment due to risk of cranial nerve complications 1
• Ramsay Hunt syndrome (herpes zoster oticus) requires valacyclovir 1 gram three times daily for 7 days plus systemic corticosteroids 6
• Ophthalmic zoster warrants ophthalmology consultation and consideration for IV therapy 1

Adjunctive Corticosteroid Therapy

• Prednisone may be used as adjunctive therapy in select cases of severe, widespread disease to reduce acute pain 1
• Corticosteroids should be added for Ramsay Hunt syndrome given facial nerve involvement 6
• Avoid corticosteroids in immunocompromised patients due to increased risk of disseminated infection 1
• Corticosteroids do not prevent postherpetic neuralgia 7

Acyclovir-Resistant Cases

• Foscarnet 40 mg/kg IV every 8 hours is the treatment of choice for acyclovir-resistant herpes zoster 1, 2
• Suspect resistance if lesions fail to begin resolving within 7-10 days of appropriate antiviral therapy 1
• Obtain viral culture with susceptibility testing when resistance is suspected 1

Critical Pitfalls to Avoid

• Never use topical antivirals as they are substantially less effective than systemic therapy 1, 6
• Do not discontinue treatment at exactly 7 days if lesions are still forming or have not completely scabbed 1, 2
• Do not delay treatment waiting for laboratory confirmation—diagnosis is clinical and treatment should begin immediately 6
• Do not use short-course genital herpes regimens (such as 1-day valacyclovir) for herpes zoster—these are inadequate for VZV infection 1

Prevention

• Recombinant zoster vaccine (Shingrix) is recommended for all adults aged 50 years and older regardless of prior herpes zoster episodes 1, 2
• Vaccination should ideally occur before initiating immunosuppressive therapies 1
• The vaccine is preferred over live-attenuated vaccine (Zostavax), which is contraindicated in immunocompromised patients 1

Post-Exposure Prophylaxis

• Varicella zoster immunoglobulin within 96 hours of exposure is recommended for varicella-susceptible patients exposed to active infection 1, 2
• If immunoglobulin is unavailable or >96 hours have passed, give oral acyclovir for 7 days beginning 7-10 days after exposure 1, 2