What is the recommended treatment for a patient presenting with herpes zoster?

Treatment of Herpes Zoster

For uncomplicated herpes zoster, initiate valacyclovir 1 gram orally three times daily for 7 days within 72 hours of rash onset, as this provides superior pain resolution compared to acyclovir while maintaining excellent tolerability. 1, 2

First-Line Antiviral Therapy

Valacyclovir is the preferred first-line agent due to superior bioavailability (3-5 fold higher than acyclovir), more convenient dosing, and significantly faster resolution of zoster-associated pain compared to acyclovir. 3, 4, 5

Standard Dosing Regimens

• Valacyclovir 1000 mg orally three times daily for 7 days is the recommended first-line treatment for uncomplicated herpes zoster. 1, 2
• Acyclovir 800 mg orally five times daily for 7 days is an effective alternative if valacyclovir is unavailable, though it requires more frequent dosing. 1, 6
• Famciclovir 500 mg orally three times daily for 7 days is another alternative with similar efficacy to valacyclovir. 1

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, 6, 2
• Treatment within 48 hours is most effective, particularly in adults over 50 years of age who show greater benefit from early intervention. 6, 2
• Delayed initiation beyond 72 hours may still provide benefit, but effectiveness is reduced. 1

Treatment Duration and Endpoints

• Continue antiviral therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period. 1, 7
• If new lesions continue to form or healing is incomplete at day 7, extend treatment beyond the standard 7-day course. 1
• Immunocompromised patients may require treatment extension well beyond 7-10 days as their lesions develop over longer periods (7-14 days) and heal more slowly. 7

Severe or Complicated Disease

For disseminated, multi-dermatomal, ophthalmic, visceral, or complicated herpes zoster, switch to intravenous acyclovir immediately. 1, 7

Indications for IV Therapy

• Disseminated herpes zoster (multi-dermatomal involvement or visceral complications including encephalitis, pneumonitis, or hepatitis) 8, 1
• Ophthalmic zoster with suspected CNS involvement or severe ocular disease 1
• Severely immunocompromised patients (e.g., those on active chemotherapy, HIV-infected with low CD4 counts) 1, 7
• Patients unable to tolerate oral therapy 1

IV Acyclovir Dosing

• Acyclovir 5-10 mg/kg IV every 8 hours until clinical improvement occurs, then switch to oral therapy to complete the treatment course. 8, 1, 2
• Continue IV therapy for a minimum of 7-10 days and until clinical resolution is attained. 1
• Monitor renal function closely during IV acyclovir therapy, with dose adjustments as needed for renal impairment. 7, 6

Special Populations

Immunocompromised Patients

• All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing of presentation. 1
• Consider temporary reduction or discontinuation of immunosuppressive therapy in severe cases of disseminated VZV infection. 1, 7
• Immunosuppression may be restarted after the patient has commenced anti-VZV therapy and skin vesicles have resolved. 1
• Monitor closely for dissemination and visceral complications. 1

Renal Impairment

• Dosage adjustment is mandatory for patients with creatinine clearance <50 mL/min to prevent acute renal failure. 6, 2
• For valacyclovir in herpes zoster with CrCl 30-49 mL/min: 1000 mg every 12 hours; CrCl 10-29 mL/min: 1000 mg every 24 hours; CrCl <10 mL/min: 500 mg every 24 hours. 2
• Maintain adequate hydration during treatment. 6

Geriatric Patients

• Acyclovir plasma concentrations are higher in geriatric patients due to age-related changes in renal function. 6
• Adults greater than 50 years of age show greater benefit from antiviral therapy, particularly when started within 48 hours. 6
• Dosage reduction may be required in geriatric patients with underlying renal impairment. 6

Acyclovir-Resistant Cases

• For suspected acyclovir-resistant herpes zoster, foscarnet 40 mg/kg IV every 8 hours is the treatment of choice. 1
• Acyclovir-resistant isolates are routinely resistant to ganciclovir as well. 1
• If lesions fail to begin resolving within 7-10 days, suspect acyclovir resistance and obtain viral culture with susceptibility testing. 7

Adjunctive Corticosteroid Therapy

Corticosteroids are NOT routinely recommended as they provide only slight benefits during the acute phase without reducing the frequency of postherpetic neuralgia, and carry significant risks particularly in elderly and immunocompromised patients. 9, 1

• A 21-day course of acyclovir or addition of prednisolone to standard 7-day acyclovir therapy confers only slight benefits over standard treatment. 9
• Neither extended acyclovir nor prednisolone reduces the frequency of postherpetic neuralgia. 9
• Prednisone should generally be avoided in immunocompromised patients due to increased risk of disseminated infection. 1

Common Pitfalls to Avoid

• Do not use topical antivirals as they are substantially less effective than systemic therapy and are not recommended. 7
• Do not discontinue treatment at exactly 7 days if lesions are still forming or have not completely scabbed. 1, 7
• Do not use short-course therapy designed for genital herpes (e.g., acyclovir 400 mg TDS) for herpes zoster, as it is inadequate for VZV infection. 7
• Do not delay treatment waiting for laboratory confirmation in typical presentations; clinical diagnosis is sufficient in immunocompetent patients. 7

Prevention and Post-Exposure Prophylaxis

• Varicella zoster immunoglobulin within 96 hours of exposure is recommended for varicella-susceptible patients exposed to active VZV infection. 1, 7
• If immunoglobulin is unavailable or >96 hours have passed, a 7-day course of oral acyclovir beginning 7-10 days after exposure is recommended. 1, 7
• The recombinant zoster vaccine (Shingrix) is recommended for all adults aged 50 years and older, regardless of prior herpes zoster episodes, to prevent future episodes. 1, 7