What is the recommended treatment for a patient diagnosed with Herpes zoster?

Treatment of Herpes Zoster

For uncomplicated herpes zoster in immunocompetent patients, initiate oral valacyclovir 1 gram three times daily for 7-10 days, continuing until all lesions have completely scabbed. 1, 2

First-Line Antiviral Therapy

Oral antiviral therapy should be initiated within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia (PHN), though treatment within 48 hours provides maximum benefit. 1, 2

Standard Treatment Options for Uncomplicated Disease:

• Valacyclovir 1 gram orally three times daily for 7-10 days is the preferred first-line agent due to superior bioavailability (3-5 fold higher than acyclovir) and convenient dosing schedule. 1, 2, 3

• Acyclovir 800 mg orally five times daily for 7-10 days is an effective alternative if valacyclovir is unavailable, though requires more frequent dosing. 1, 2, 4

• Famciclovir 500 mg orally three times daily for 7 days offers comparable efficacy with better bioavailability than acyclovir and is the only oral antiviral proven to reduce PHN duration (median reduction of 100 days in patients ≥50 years). 1, 5

Critical treatment endpoint: Continue therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period—treatment may need extension beyond 7-10 days if active lesions persist. 1, 2

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 organ involvement) 1, 2, 6
• Severely immunocompromised patients (chemotherapy, HIV with low CD4 counts, solid organ transplant recipients) 1, 6
• Complicated facial zoster with suspected CNS involvement or severe ophthalmic disease 1
• Patients who develop cutaneous or visceral dissemination despite oral therapy 1, 6

Higher doses (10 mg/kg every 8 hours) are preferred for severely immunocompromised hosts to achieve plasma levels necessary to control VZV replication. 1, 6

Treatment duration: Continue IV acyclovir for minimum 7-10 days and until clinical resolution is attained (all lesions scabbed, no new lesions forming, resolution of visceral complications if present), then switch to oral therapy to complete the course. 2, 6

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, 6
• Immunosuppression may be restarted after commencing anti-VZV therapy and complete resolution of skin vesicles. 6
• Monitor closely for dissemination, visceral complications, and acyclovir resistance (if lesions persist despite adequate therapy). 1, 2
• Immunocompromised patients may require treatment extension well beyond 7-10 days as lesions continue to develop over longer periods (7-14 days) and heal more slowly. 1

Elderly Patients (≥50 years):

• This population is at greatest risk for PHN and derives maximum benefit from antiviral therapy. 3, 5, 7
• Valacyclovir significantly accelerates pain resolution compared to acyclovir (median 38 days vs 51 days) and reduces PHN duration. 3
• Dose adjustments may be required due to age-related renal impairment. 4

Renal Impairment:

• Mandatory dose adjustments are required to prevent acute renal failure. 1
• Monitor renal function closely during IV acyclovir therapy, with assessments at initiation and once or twice weekly during treatment. 1
• For famciclovir: adjust to 500 mg every 24 hours for CrCl 20-39 mL/min. 1, 2

Acyclovir-Resistant Cases

For proven or suspected acyclovir-resistant herpes zoster (lesions persisting despite adequate therapy):

• Foscarnet 40 mg/kg IV every 8 hours until clinical resolution is the treatment of choice. 1, 2
• All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir and ganciclovir. 1, 2
• Obtain viral culture with susceptibility testing if lesions fail to resolve within 7-10 days. 1
• Foscarnet requires close monitoring of renal function and electrolytes (hypocalcemia, hypophosphatemia, hypomagnesemia, hypokalemia). 2

Adjunctive Therapies and Caveats

What NOT to Do:

• Topical antiviral therapy is substantially less effective than systemic therapy and is NOT recommended. 1, 2
• Topical corticosteroids on active shingles lesions are contraindicated due to risk of severe disease and dissemination, particularly in immunocompromised patients. 1
• Oral corticosteroids may be considered as adjunctive therapy in select cases of severe, widespread disease, but carry significant risks (infections, hypertension, myopathy, glaucoma, osteopenia) that generally outweigh benefits. 1

Infection Control:

• Patients must avoid contact with susceptible individuals until all lesions have crusted as lesions are contagious to those without prior chickenpox or vaccination. 1
• Cover lesions with clothing or dressings to minimize transmission risk. 1
• For disseminated zoster, implement both airborne and contact precautions. 1

Post-Exposure Prophylaxis

For varicella-susceptible patients exposed to active VZV infection:

• Varicella zoster immunoglobulin (VZIG) within 96 hours of exposure is recommended for high-risk individuals (pregnant women, immunocompromised patients, premature newborns). 1, 2
• If VZIG unavailable or >96 hours have passed: 7-day course of oral acyclovir beginning 7-10 days after exposure. 1, 2

Prevention

The recombinant zoster vaccine (Shingrix) is strongly recommended for all adults aged ≥50 years, regardless of prior herpes zoster episodes, with >90% efficacy in preventing future recurrences. 1, 2 Vaccination should ideally occur before initiating immunosuppressive therapies and can be administered after recovery from acute herpes zoster. 1