Treatment of Herpes Zoster
For uncomplicated herpes zoster, initiate oral valacyclovir 1 gram three times daily for 7 days, which is the preferred first-line treatment due to superior bioavailability and convenient dosing. 1, 2
First-Line Oral Antiviral Options
Valacyclovir is the preferred agent for uncomplicated herpes zoster in immunocompetent patients, offering better bioavailability than acyclovir and requiring only three-times-daily dosing rather than five times daily. 1, 2, 3
Alternative oral regimens include:
- Famciclovir 500 mg orally three times daily for 7 days – equally effective to valacyclovir with convenient dosing 1, 2, 4
- Acyclovir 800 mg orally five times daily for 7 days – effective but requires more frequent dosing 1, 5
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, 5 However, treatment beyond 72 hours may still provide benefit, particularly in immunocompromised patients or those with severe disease. 1
Treatment Duration and Endpoints
Continue antiviral therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period. 1, 5 This is the key clinical endpoint that determines treatment completion. 1 In immunocompromised patients, lesions may continue to develop for 7-14 days and heal more slowly, requiring treatment extension well beyond the standard 7-10 days. 5
Severe or Disseminated Disease
For disseminated, multi-dermatomal, ophthalmic, visceral, or complicated herpes zoster, initiate intravenous acyclovir 5-10 mg/kg every 8 hours. 1, 5, 2 This includes:
- Immunocompromised patients with herpes zoster 1, 5
- Multi-dermatomal involvement 1
- CNS complications 5
- Complicated ocular disease 5
- Visceral organ involvement 5
Treatment should continue for a minimum of 7-10 days and until clinical resolution is attained, then switch to oral therapy to complete the course. 1, 2
Consider temporary reduction in immunosuppressive medications in severe cases of disseminated VZV infection, with immunosuppression restarted after the patient has commenced anti-VZV therapy and skin vesicles have resolved. 1, 5
Special Populations and Considerations
Immunocompromised Patients
All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing. 1 These patients are at higher risk for dissemination, visceral complications, and chronic ulcerations with persistent viral replication. 1, 5, 2
Monitor closely for dissemination and complications, including secondary bacterial or fungal superinfections. 1, 2
V1 (Ophthalmic) Distribution
For V1 herpes zoster, valacyclovir 1 gram orally three times daily for 7 days is preferred, with careful monitoring for ocular involvement and consideration of ophthalmology consultation if ocular involvement is present. 2
Acyclovir-Resistant Cases
For suspected acyclovir-resistant herpes zoster, foscarnet 40 mg/kg IV every 8 hours is recommended, as acyclovir-resistant isolates are routinely resistant to ganciclovir as well. 1, 5
Post-Exposure Prophylaxis
For varicella-susceptible patients exposed to active varicella zoster infection, administer varicella zoster immunoglobulin within 96 hours of exposure. 1, 5 If immunoglobulin is unavailable or more than 96 hours have passed, initiate a 7-day course of oral acyclovir beginning 7-10 days after exposure. 1, 5
Prevention
The recombinant zoster vaccine (Shingrix) is recommended for all adults aged 50 years and older, regardless of prior herpes zoster episodes, ideally administered before initiating immunosuppressive therapies. 1, 5 This vaccine is preferred over the live-attenuated vaccine and can be considered after recovery to prevent future episodes. 5
Critical Pitfalls to Avoid
- Do not rely on topical antiviral therapy – it is substantially less effective than systemic therapy and is not recommended. 5
- Do not stop treatment at 7 days if lesions remain active – continue until all lesions have scabbed. 1, 5
- Do not use standard HSV dosing – herpes zoster requires higher doses (e.g., acyclovir 800 mg five times daily, not 400 mg). 5
- Do not delay IV therapy in immunocompromised patients with severe disease – oral therapy should be reserved for mild cases only. 2
- Monitor renal function closely during IV acyclovir therapy with dose adjustments as needed for renal impairment. 5