What is the recommended treatment approach for a patient presenting with shingles, considering their age, medical history, and current health status?

Treatment of Shingles (Herpes Zoster)

For immunocompetent adults with shingles, initiate oral valacyclovir 1 gram three times daily for 7 days within 72 hours of rash onset, continuing treatment until all lesions have completely scabbed. 1

Antiviral Therapy Selection

First-line treatment options include:

• Valacyclovir 1000 mg orally three times daily for 7 days is the preferred agent due to superior bioavailability (3-5 fold higher than acyclovir), more convenient dosing, and demonstrated superiority in accelerating pain resolution compared to acyclovir 1, 2, 3

• Acyclovir 800 mg orally five times daily for 7-10 days remains an effective alternative, though requires more frequent dosing 4, 5

• Famciclovir 500 mg orally three times daily for 7 days offers similar efficacy to valacyclovir with comparable convenience 3, 6

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 5, 1, 7. However, treatment initiated beyond 72 hours may still provide benefit and should not be withheld 3.

Treatment Duration and Monitoring

Continue antiviral therapy until all lesions have completely scabbed, not just for an arbitrary 7-day period. 5 This is the key clinical endpoint that determines treatment completion.

• Immunocompetent patients typically develop new lesions for 4-6 days with total disease duration of approximately 2 weeks 5

• If lesions continue to form or have not scabbed by day 7, extend treatment duration 5

• Monitor for treatment failure; if lesions fail to begin resolving within 7-10 days, suspect acyclovir resistance and obtain viral culture with susceptibility testing 5

Special Populations Requiring Modified Approach

Immunocompromised Patients

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

• Severely immunocompromised patients (HIV, active chemotherapy, chronic immunosuppression) 5
• Disseminated or invasive herpes zoster (multi-dermatomal, visceral involvement) 4, 5
• CNS complications or complicated ocular disease 5
• Patients on chemotherapy with chest wall involvement 5

Treatment duration: Continue IV therapy for minimum 7-10 days and until clinical resolution (all lesions completely scabbed) 5

Consider temporary reduction in immunosuppressive medications in patients with disseminated or invasive disease 5

Monitor renal function at initiation and once or twice weekly during IV acyclovir therapy, with dose adjustments for renal impairment 5, 1

Pregnant Women

Administer VZIG (varicella zoster immune globulin) within 96 hours after exposure for VZV-susceptible pregnant women 4, 5

Patients with Renal Impairment

Dose adjustments are mandatory to prevent acute renal failure 5, 1:

• Creatinine clearance 30-49 mL/min: Valacyclovir 1 gram every 12 hours
• Creatinine clearance 10-29 mL/min: Valacyclovir 1 gram every 24 hours
• Creatinine clearance <10 mL/min: Valacyclovir 500 mg every 24 hours 1

Acyclovir-Resistant Cases

For proven or suspected acyclovir resistance:

• Foscarnet 40 mg/kg IV every 8 hours until clinical resolution is the treatment of choice 4, 5
• All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir 5
• Topical cidofovir gel 1% applied once daily for 5 consecutive days may be considered as an alternative 5

Critical Pitfalls to Avoid

Do NOT use:

• Topical antivirals - substantially less effective than systemic therapy and not recommended 4, 5
• Topical corticosteroid creams on active vesicular lesions - can increase risk of severe disease and dissemination, particularly in immunocompromised patients 5
• Short-course therapy designed for genital herpes (e.g., acyclovir 400 mg three times daily) - inadequate for VZV infection 5

Oral corticosteroids (prednisone):

• May provide modest benefits in reducing acute pain but carry significant risks (infections, hypertension, myopathy, glaucoma, osteopenia) that generally outweigh benefits 5, 7
• Should be avoided in immunocompromised patients due to increased risk of disseminated infection 5
• If used, only as adjunctive therapy to antivirals in select cases of severe, widespread disease in immunocompetent patients 5

Infection Control

Patients must avoid contact with susceptible individuals (those who have not had chickenpox, pregnant women, immunocompromised persons) until all lesions have crusted, as lesions are contagious 5

Prevention of Future Episodes

Recombinant zoster vaccine (Shingrix) is recommended for all adults aged 50 years and older, regardless of prior herpes zoster episodes, ideally administered after recovery from acute episode 8, 5