What is the recommended management for a patient, likely an adult over 50 with a history of chickenpox and possible underlying conditions such as diabetes, cancer, or HIV/AIDS, presenting with shingles?

Management of Shingles (Herpes Zoster)

Antiviral Therapy: First-Line Treatment

For adults presenting with shingles, initiate oral antiviral therapy with valacyclovir 1000 mg three times daily, famciclovir 500 mg three times daily, or acyclovir 800 mg five times daily within 72 hours of rash onset, continuing treatment until all lesions have completely scabbed—not for an arbitrary 7-day period. 1, 2

Optimal Timing and Duration

• Treatment is most effective when started within 48-72 hours of rash onset, though benefit may extend beyond 72 hours 2, 3
• Continue antiviral therapy until all lesions have completely scabbed, which is the key clinical endpoint 1, 2
• For immunocompetent patients, this typically takes 7-10 days, but treatment must be extended if lesions remain active beyond this timeframe 1, 4
• Immunocompromised patients may require treatment well beyond 7-10 days as their lesions continue to develop for 7-14 days and heal more slowly 2

Comparative Efficacy of Oral Antivirals

• Valacyclovir (1000 mg three times daily) is superior to acyclovir in reducing the duration of zoster-associated pain and postherpetic neuralgia 5, 3
• Valacyclovir accelerated pain resolution to a median of 38 days versus 51 days with acyclovir 5
• Famciclovir (500 mg three times daily) reduced the median duration of postherpetic neuralgia by 3.5 months in patients ≥50 years compared to placebo 6
• All three agents have similar efficacy for acute cutaneous manifestations, but valacyclovir and famciclovir offer more convenient dosing (three times daily versus five times daily for acyclovir) 3, 7

Escalation to Intravenous Therapy

Switch to intravenous acyclovir 10 mg/kg every 8 hours for disseminated or invasive herpes zoster, severely immunocompromised patients, CNS complications, or complicated ocular disease. 2

Indications for IV Therapy

• Disseminated herpes zoster (multi-dermatomal or visceral involvement) 2
• Immunocompromised patients on active chemotherapy or with conditions like HIV, cancer, or organ transplantation 2
• Complicated facial zoster with suspected CNS involvement 2
• Severe ophthalmic disease 2
• Continue IV therapy for minimum 7-10 days and until clinical resolution is attained 1, 2

Special Considerations for Immunocompromised Patients

• Consider temporary reduction in immunosuppressive medications during treatment of disseminated disease 2
• Monitor renal function closely during IV acyclovir therapy with dose adjustments for renal impairment 2, 4
• If lesions fail to resolve within 7-10 days despite treatment, suspect acyclovir resistance and obtain viral culture with susceptibility testing 2

Management of Acyclovir-Resistant Cases

For proven or suspected acyclovir-resistant herpes zoster, switch to foscarnet 40 mg/kg IV every 8 hours until clinical resolution. 2

• All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir 2
• Topical cidofovir gel 1% applied once daily for 5 consecutive days may be an alternative option 2

Infection Control and Skin Care

• Patients must avoid contact with susceptible individuals (pregnant women, immunocompromised persons, those without chickenpox history) until all lesions have crusted 1, 2
• Elevation of the affected area promotes drainage of edema and inflammatory substances 1, 2
• After lesions have crusted, emollients may be used to prevent excessive dryness, but avoid applying any products to active vesicular lesions 1, 2

Pain Management Considerations

• Antiviral therapy reduces acute pain intensity and duration when started within 72 hours 7, 5
• Valacyclovir and famciclovir are superior to acyclovir for reducing postherpetic neuralgia duration 5, 6
• Topical anesthetics provide minimal benefit and are not recommended as primary therapy 2

Vaccination for Secondary Prevention

Administer the recombinant zoster vaccine (Shingrix) to all adults aged 50 years and older, regardless of prior herpes zoster episodes, to prevent future recurrences. 1, 2

• Shingrix is preferred over the live attenuated vaccine (Zostavax), especially for immunocompromised patients 1
• Vaccination should ideally occur before initiating immunosuppressive therapies 2
• For patients who have just had shingles, vaccination can be considered after recovery 2

Critical Pitfalls to Avoid

• Do not discontinue antiviral therapy at exactly 7 days if lesions are still forming or have not completely scabbed 1, 2
• Do not use topical antivirals, as they are substantially less effective than systemic therapy 2
• Do not apply corticosteroid creams to active shingles lesions, as this can increase the risk of severe disease and dissemination, especially in immunocompromised patients 1, 2
• Do not use acyclovir 400 mg three times daily—this dose is only appropriate for genital herpes or HSV suppression, not for shingles 2
• For HIV-positive patients with herpes zoster, higher oral doses (up to 800 mg 5-6 times daily) may be needed 2

Special Population Considerations

Patients with Diabetes, Cancer, or HIV/AIDS

• These patients are at higher risk for disseminated disease and complications 2
• Consider IV acyclovir rather than oral therapy, particularly if on active immunosuppressive treatment 2
• Monitor for acyclovir resistance if lesions persist despite adequate treatment 2
• Consider daily suppressive therapy with acyclovir, famciclovir, or valacyclovir for patients with frequent or severe recurrences 8, 1

Pregnant Women

• VZIG is recommended for VZV-susceptible pregnant women within 96 hours after exposure to active varicella zoster infection 8, 2
• If oral acyclovir is used, VZV serology should be performed so that the drug can be discontinued if the patient is seropositive 8

Renal Impairment

• Dose adjustments are mandatory to prevent acute renal failure 2, 4
• The half-life and total body clearance of acyclovir are dependent on renal function 4
• Geriatric patients often require dosage reduction due to age-related changes in renal function 4