What is the primary treatment for a typical adult patient with herpes zoster?

Treatment of Herpes Zoster

First-Line Treatment for Uncomplicated Herpes Zoster

For a typical adult patient with uncomplicated herpes zoster, oral valacyclovir 1 gram three times daily for 7 days is the recommended first-line treatment, initiated within 72 hours of rash onset. 1, 2

Alternative Oral Antiviral Options

• Acyclovir 800 mg orally five times daily for 7-10 days is an effective alternative if valacyclovir is unavailable, though it requires more frequent dosing 1, 2, 3
• Famciclovir 500 mg every 8 hours for 7 days offers comparable efficacy with better bioavailability than acyclovir and less frequent dosing than the five-times-daily acyclovir regimen 1, 4, 5

Critical Treatment Timing and Duration

• 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, 2, 5
• Continue treatment until all lesions have completely scabbed, not just for an arbitrary 7-day period—this is the key clinical endpoint 1, 2
• Treatment initiated within 48 hours provides maximum benefit, though the 72-hour window remains the standard cutoff 1

Escalation to Intravenous Therapy

Intravenous acyclovir 5-10 mg/kg every 8 hours is mandatory for:

• Disseminated or invasive herpes zoster (multi-dermatomal involvement, visceral complications) 1, 2
• Severely immunocompromised patients (active chemotherapy, HIV with low CD4 counts, solid organ transplant recipients) 1, 2
• Complicated facial zoster with suspected CNS involvement or severe ophthalmic disease 1
• Patients who cannot tolerate or absorb oral medications 1, 2

For IV therapy, continue treatment for a minimum of 7-10 days and until clinical resolution is attained, then switch to oral therapy once clinical improvement occurs 1, 2

Special Population Considerations

Immunocompromised Patients

• All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing beyond the 72-hour window 2
• Consider temporary reduction or discontinuation of immunosuppressive medications in cases of disseminated or invasive disease if clinically feasible 1, 2
• Monitor closely for dissemination, visceral complications, and chronic ulcerations with persistent viral replication 1, 2
• Immunosuppression may be restarted after commencing anti-VZV therapy and after skin vesicles have resolved 2

Renal Impairment

• Mandatory dose adjustments are required to prevent acute renal failure 1
• For famciclovir: 500 mg every 8 hours for CrCl ≥60 mL/min, down to 250 mg every 24 hours for CrCl <20 mL/min 1, 4
• Monitor renal function closely during IV acyclovir therapy with dose adjustments as needed 1

Adjunctive Pain Management

While antiviral therapy is the cornerstone of treatment, adjunctive analgesics may be necessary for acute zoster pain:

• Opioid analgesics for severe pain during the acute phase 3, 6
• Tricyclic antidepressants or anticonvulsants (gabapentin, pregabalin) may help control neuropathic pain 3, 6
• Topical anesthetics provide minimal benefit and are not recommended as primary therapy 1

Role of Corticosteroids

Corticosteroids offer only modest benefits and carry significant risks:

• Prednisone may be used as adjunctive therapy in select cases of severe, widespread disease, but benefits are limited to slight improvement in acute pain reduction 1, 7
• Corticosteroids do not reduce the frequency of postherpetic neuralgia 7
• Avoid in immunocompromised patients due to increased risk of disseminated infection 1
• Contraindicated in patients with poorly controlled diabetes, severe osteoporosis, or history of steroid-induced complications 1

Treatment Failures and Resistance

If lesions fail to begin resolving within 7-10 days:

• Suspect acyclovir resistance and obtain viral culture with susceptibility testing 1
• For confirmed acyclovir-resistant herpes zoster, foscarnet 40 mg/kg IV every 8 hours is the treatment of choice 1, 2
• All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir 1
• Resistance is extremely rare in immunocompetent patients but occurs more frequently in immunocompromised patients receiving prolonged suppressive therapy 1

Prevention Strategies

Vaccination

The recombinant zoster vaccine (Shingrix) is strongly recommended for all adults aged 50 years and older, regardless of prior herpes zoster episodes 8, 1, 2

• Provides >90% efficacy in preventing future recurrences 1
• Should be administered after recovery from the current episode 1
• Ideally given before initiating immunosuppressive therapies 1
• The live attenuated vaccine (Zostavax) is contraindicated in immunocompromised patients 8, 1

Post-Exposure Prophylaxis

• Varicella-zoster immunoglobulin (VZIG) within 96 hours of exposure is recommended for VZV-susceptible patients exposed to active infection 1, 2
• 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, 2

Infection Control

• Patients should avoid contact with susceptible individuals until all lesions have crusted, as lesions are contagious to those who have not had chickenpox or vaccination 1
• Cover lesions with clothing or dressings to minimize transmission risk 1
• Healthcare workers with herpes zoster should be excluded from duty until all lesions dry and crust 1

Common Pitfalls to Avoid

• Do not use topical antiviral therapy—it is substantially less effective than systemic therapy 1, 2
• Do not discontinue treatment at exactly 7 days if lesions are still forming or have not completely scabbed—treatment duration should be guided by lesion healing, not calendar days 1, 2
• Do not rely on clinical diagnosis alone in immunocompromised patients or atypical presentations—laboratory confirmation is needed 1
• Do not use acyclovir 400 mg TDS—this dose is only appropriate for genital herpes or HSV suppression, not for shingles 1