What is the recommended treatment for herpes zoster (shingles) in an adult?

Treatment of Herpes Zoster (Shingles) in Adults

For uncomplicated herpes zoster in immunocompetent adults, initiate oral valacyclovir 1 gram three times daily for 7–10 days, starting within 72 hours of rash onset and continuing until all lesions have completely scabbed. 1, 2, 3

First-Line Oral Antiviral Therapy

Valacyclovir is the preferred first-line agent due to superior bioavailability, less frequent dosing (three times daily versus five times daily for acyclovir), and demonstrated superiority in reducing the duration of zoster-associated pain and postherpetic neuralgia compared to acyclovir. 1, 4

Standard Dosing Regimens

• Valacyclovir: 1000 mg orally three times daily for 7–10 days 1, 2, 3
• Famciclovir: 500 mg orally three times daily for 7–10 days 1, 5, 6
• Acyclovir: 800 mg orally five times daily for 7–10 days 1, 2

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 However, treatment initiated beyond 72 hours may still provide benefit, particularly for pain reduction, and should not be withheld in patients presenting late. 4

Continue treatment until all lesions have completely scabbed, not just for an arbitrary 7-day period—this is the key clinical endpoint. 1, 2 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. 1

Intravenous Therapy for Severe or Complicated Disease

Switch to intravenous acyclovir 10 mg/kg every 8 hours for any of the following indications: 1, 2

• Disseminated herpes zoster (≥3 dermatomes, visceral involvement, or hemorrhagic lesions)
• Severe immunosuppression (active chemotherapy, HIV with low CD4 count, organ transplant recipients)
• CNS complications (encephalitis, meningitis, Guillain-Barré syndrome)
• Complicated ophthalmic or facial disease
• Failure to improve on oral therapy within 7–10 days

Continue IV acyclovir for a minimum of 7–10 days and until clinical resolution is attained (all lesions completely scabbed), then switch to oral therapy to complete the treatment course. 1, 2

Critical Monitoring During IV Therapy

• Assess renal function at initiation and monitor once or twice weekly during IV acyclovir therapy, with mandatory dose adjustments for any renal impairment. 1, 2
• Ensure adequate hydration during systemic acyclovir or valacyclovir therapy to reduce the risk of crystalluria and acyclovir-induced nephropathy. 1
• Monitor for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients receiving high-dose therapy. 1

Management of Immunocompromised Patients

All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing. 1, 2 For uncomplicated disease, oral valacyclovir or famciclovir at standard doses is appropriate, but consider intravenous acyclovir 10 mg/kg every 8 hours for patients on active chemotherapy (e.g., daratumumab, bortezomib, melphalan) or with severely compromised immunity. 1

Temporarily reduce or discontinue immunosuppressive medications in cases of disseminated or invasive herpes zoster if clinically feasible. 1, 2 Re-introduction of immunosuppressive agents is recommended only after all vesicular lesions have crusted, fever has resolved, and the patient has shown clinical improvement on antiviral therapy. 1

Prophylaxis in High-Risk Patients

• Acyclovir 400 mg daily or valacyclovir prophylaxis is recommended for patients receiving proteasome inhibitor-based therapies (e.g., bortezomib) to prevent herpes zoster. 1
• Varicella zoster immunoglobulin (VZIG) within 96 hours of exposure is recommended for varicella-susceptible patients exposed to active varicella zoster infection, including pregnant women, immunocompromised patients, and premature newborns. 1, 2
• If VZIG is unavailable or >96 hours have passed, administer a 7-day course of oral acyclovir beginning 7–10 days after varicella exposure. 1, 2

Treatment of Acyclovir-Resistant Herpes Zoster

Suspect acyclovir resistance when cutaneous lesions have not begun to resolve within 7–10 days after starting therapy. 1, 2 Confirmation requires obtaining a viral culture with susceptibility testing. 1

For confirmed acyclovir-resistant VZV, switch to foscarnet 40 mg/kg IV every 8 hours until clinical resolution. 1, 2 All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir. 1

Acyclovir resistance is extremely rare in immunocompetent patients but occurs in up to 7% of immunocompromised patients, particularly those receiving prolonged suppressive therapy. 1

Pain Management for Acute Herpes Zoster

Gabapentin is the first-line oral agent for acute neuropathic pain due to herpes zoster, titrated in divided doses up to 2400 mg per day. 1 Gabapentin improves sleep quality but causes somnolence in approximately 80% of treated individuals. 1

Pregabalin may be added for patients whose pain remains uncontrolled with gabapentin alone, particularly in postherpetic neuralgia. 1

A single application of an 8% capsaicin patch (or a 30-minute cream application) provides analgesia lasting at least 12 weeks for chronic peripheral neuropathic pain. 1 To mitigate erythema and burning, apply a 4% lidocaine preparation for 60 minutes, then remove before capsaicin administration. 1

Over-the-counter analgesics such as acetaminophen and ibuprofen are recommended to relieve acute pain in otherwise healthy adults. 1 Application of topical ice or cold packs can reduce pain and swelling during the acute phase. 1

Corticosteroid Use: Significant Risks Outweigh Benefits

Corticosteroids should generally be avoided in herpes zoster treatment due to serious risks including increased susceptibility to infections, hypertension, myopathy, glaucoma, aseptic necrosis, cataracts, Cushing syndrome, weight gain, and osteopenia—benefits in pain reduction do not outweigh these risks in most patients. 1

Corticosteroids are absolutely contraindicated in immunocompromised patients (HIV, cancer, chronic systemic immunosuppression) during active shingles due to increased risk of severe disease and dissemination. 1 Patients with poorly controlled diabetes, history of steroid-induced psychosis, severe osteoporosis, or prior severe steroid toxicity should avoid prednisone. 1

Infection Control and Prevention of Transmission

Patients with herpes zoster must avoid contact with susceptible individuals until all lesions have crusted, as lesions are contagious to individuals who have not had chickenpox or vaccination. 1, 2

• 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
• For disseminated zoster (lesions in >3 dermatomes), implement both airborne and contact precautions in addition to standard precautions. 1
• Physical separation of at least 6 feet from other patients is recommended in healthcare settings. 1

Vaccination After Recovery

The recombinant zoster vaccine (Shingrix) is strongly recommended for all adults aged ≥50 years, regardless of prior herpes zoster episodes, providing >90% efficacy in preventing future recurrences. 1, 7

Administer Shingrix no earlier than 2 months after complete clinical resolution of the acute episode, allowing lesion healing and immune recovery to optimize vaccine response. 7 The 2-dose series should be given 2–6 months apart. 7

Live-attenuated zoster vaccine (Zostavax) is absolutely contraindicated in immunocompromised patients due to risk of uncontrolled vaccine-strain viral replication. 1, 7 Only the recombinant vaccine (Shingrix) is appropriate for immunocompromised individuals. 7

Common Pitfalls to Avoid

• Do not use topical antivirals—they are substantially less effective than systemic therapy and are not recommended. 1, 2
• Do not discontinue antiviral therapy at exactly 7 days if lesions are still forming or have not completely scabbed. 1, 2
• Do not use short-course therapy (1–3 days) designed for genital herpes—it is inadequate for VZV infection. 1
• Do not apply corticosteroid creams to active shingles rash—this can increase risk of severe disease and dissemination, particularly in immunocompromised patients. 1
• Do not delay treatment beyond 72 hours when possible, though late treatment may still provide benefit for pain reduction. 1, 4