What is the recommended treatment for a patient presenting with active blisters due to shingles?

Treatment of Active Blisters with Shingles

For patients presenting with active blisters due to shingles, initiate oral valacyclovir 1000 mg three times daily or famciclovir 500 mg three times daily immediately, continuing treatment until all lesions have completely scabbed, typically 7-10 days. 1

First-Line Antiviral Therapy

Valacyclovir and famciclovir are preferred over acyclovir due to superior bioavailability, less frequent dosing (improving adherence), and faster resolution of zoster-associated pain. 2, 3, 4

Recommended Regimens:

• Valacyclovir 1000 mg orally three times daily for 7-10 days 1, 2
• Famciclovir 500 mg orally three times daily for 7-10 days 1, 5
• Acyclovir 800 mg orally five times daily for 7-10 days (alternative if valacyclovir/famciclovir unavailable) 1

Critical timing: 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 However, evidence suggests benefit even when started after 72 hours, so do not withhold treatment in late presenters. 2

Treatment Duration and Endpoint

Continue antiviral therapy until all lesions have completely scabbed—this is the key clinical endpoint, not an arbitrary 7-day duration. 1 If lesions remain active beyond 7 days, extend treatment accordingly. 1 Immunocompromised patients may require treatment well beyond 7-10 days as their lesions develop over longer periods (7-14 days) and heal more slowly. 1

When to Escalate to Intravenous Therapy

Switch to IV acyclovir 10 mg/kg every 8 hours for: 1

• Disseminated herpes zoster (multi-dermatomal or visceral involvement)
• Severely immunocompromised patients (chemotherapy, HIV, organ transplant)
• CNS complications or complicated ocular disease
• Inability to tolerate oral medications

For immunocompromised patients on chemotherapy or similar therapy, IV acyclovir is mandatory due to high risk of dissemination and complications. 1 Continue IV therapy for at least 7-10 days until all lesions have completely scabbed. 1

Adjunctive Corticosteroid Therapy: Generally Not Recommended

Corticosteroids should generally be avoided in shingles treatment. While prednisone may provide slight benefit in acute pain reduction during the first 7-14 days, it does not reduce the frequency of postherpetic neuralgia and carries significant risks including increased infection susceptibility, hypertension, myopathy, glaucoma, and osteopenia. 6, 1

Absolute contraindications to corticosteroids: 1

• Immunocompromised patients (HIV, cancer, chronic immunosuppression)
• Active disseminated infection
• Poorly controlled diabetes
• Severe osteoporosis

Special Population Considerations

Immunocompromised Patients:

• Higher oral doses may be needed: Acyclovir 400 mg orally 3-5 times daily until clinical resolution 1
• Consider temporary reduction of immunosuppressive medications in cases of disseminated or invasive herpes zoster if clinically feasible 1
• Monitor closely for acyclovir resistance if lesions persist despite treatment; switch to foscarnet 40 mg/kg IV every 8 hours if resistance confirmed 1

Renal Impairment:

Mandatory dose adjustments to prevent acute renal failure. For famciclovir in herpes zoster: 1

• CrCl ≥60 mL/min: 500 mg every 8 hours
• CrCl 40-59 mL/min: 500 mg every 12 hours
• CrCl 20-39 mL/min: 500 mg every 24 hours
• CrCl <20 mL/min: 250 mg every 24 hours

Monitor renal function at initiation and once or twice weekly during IV acyclovir therapy. 1

What NOT to Do

• Never use topical antivirals—they are substantially less effective than systemic therapy and are not recommended. 1, 7
• Do not discontinue treatment at exactly 7 days if lesions are still forming or have not completely scabbed. 1
• Avoid applying corticosteroid creams directly to active shingles lesions—this can increase risk of severe disease and dissemination, especially in immunocompromised patients. 1

Infection Control

Patients must avoid contact with susceptible individuals (pregnant women, immunocompromised persons, those without chickenpox immunity) until all lesions have crusted. 1 Cover lesions with clothing or dressings to minimize transmission risk. 1

Post-Recovery Prevention

Strongly recommend the recombinant zoster vaccine (Shingrix) for all adults aged 50 years and older after recovery from the current episode, regardless of prior herpes zoster episodes. 1 This provides >90% efficacy in preventing future recurrences. 1