What is the appropriate management for herpes zoster in an adult patient?

Management of Herpes Zoster in Adults

For uncomplicated herpes zoster in immunocompetent adults, initiate oral valacyclovir 1 gram three times daily for 7-10 days, continuing treatment until all lesions have completely scabbed. 1, 2, 3

First-Line Antiviral Treatment

Oral antiviral therapy should be started within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia. 1, 3 However, treatment initiated beyond 72 hours may still provide benefit and should not be withheld. 4

Standard Oral Regimens for Immunocompetent Patients

• Valacyclovir 1 gram orally three times daily for 7-10 days (preferred due to superior bioavailability and less frequent dosing) 1, 2, 3, 5
• Famciclovir 500 mg orally three times daily for 7-10 days (equivalent efficacy to valacyclovir with convenient dosing) 1, 4
• Acyclovir 800 mg orally five times daily for 7-10 days (effective but requires more frequent dosing) 1, 2, 3, 6

The critical treatment endpoint is complete scabbing of all lesions, not an arbitrary 7-day duration. 1, 2 If lesions continue to form or have not completely scabbed at 7 days, extend treatment until clinical resolution is achieved. 1, 2

Escalation to Intravenous Therapy

Switch to intravenous acyclovir 5-10 mg/kg every 8 hours for:

• Disseminated or multi-dermatomal herpes zoster 1, 2
• Visceral involvement or CNS complications 1, 2
• Severely immunocompromised patients (including those on active chemotherapy, HIV-infected with low CD4 counts, or solid organ transplant recipients) 1, 2
• Complicated ophthalmic zoster with suspected ocular involvement 1
• Failure to respond to oral therapy 1

Continue IV therapy for a minimum of 7-10 days and until clinical resolution is attained, then switch to oral therapy to complete the treatment course. 2 In severely immunocompromised patients, consider temporary reduction in immunosuppressive medications during treatment of disseminated disease. 1, 2

Special Populations

Immunocompromised Patients

All immunocompromised patients with herpes zoster require antiviral treatment regardless of timing from rash onset. 2 This includes patients with:

• Active malignancy on chemotherapy (particularly those receiving proteasome inhibitors, monoclonal antibodies, or purine analogs) 1
• HIV infection 1
• Solid organ or bone marrow transplant recipients 1
• Inflammatory bowel disease on immunosuppressive therapy 1

For uncomplicated herpes zoster in kidney transplant recipients or stable immunocompromised patients, use oral valacyclovir or acyclovir with close monitoring for dissemination. 1 However, maintain a low threshold for switching to IV therapy if any signs of progression develop. 1, 2

Renal Impairment

Dose adjustments are mandatory for all oral antivirals in patients with renal impairment to prevent acute renal failure. 1 For valacyclovir in herpes zoster, adjust based on creatinine clearance. 1 Monitor renal function at initiation and once or twice weekly during IV acyclovir therapy. 1

Pregnant Women

Valacyclovir is FDA pregnancy category B and may be used for herpes zoster treatment when clinically indicated. 2 For varicella-susceptible pregnant women exposed to active varicella zoster infection, administer varicella zoster immunoglobulin (VZIG) within 96 hours of exposure. 1

Post-Exposure Prophylaxis

For varicella-susceptible patients exposed to active varicella zoster infection:

• Administer varicella zoster immunoglobulin (or IVIG) within 96 hours of exposure 1, 2
• If immunoglobulin is unavailable or >96 hours have passed, initiate a 7-day course of oral acyclovir beginning 7-10 days after exposure 1, 2

This applies particularly to high-risk populations including HIV-infected patients, pregnant women, and other immunocompromised individuals. 1

Acyclovir-Resistant Cases

For suspected acyclovir-resistant herpes zoster (lesions persisting despite adequate treatment), switch to foscarnet 40 mg/kg IV every 8 hours. 1, 2 Obtain viral culture with susceptibility testing to confirm resistance. 1 Acyclovir-resistant isolates are routinely resistant to ganciclovir as well. 2

Prevention Through Vaccination

The recombinant zoster vaccine (Shingrix) is strongly recommended for all immunocompetent adults aged ≥50 years, regardless of prior herpes zoster episodes. 7, 1 The vaccine is given in 2 doses, 2-6 months apart. 7 For immunocompromised patients aged ≥19 years, the recombinant vaccine is also recommended. 7 Ideally, vaccination should occur before initiating immunosuppressive therapies. 1

Common Pitfalls to Avoid

• Do not discontinue treatment 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 1
• Do not delay treatment in immunocompromised patients waiting for the 72-hour window—treat immediately 1, 2
• Do not use inadequate acyclovir dosing (e.g., 400 mg TDS is only appropriate for genital herpes, not shingles) 1
• Do not overlook the need for dose adjustment in renal impairment 1
• Do not assume live-attenuated zoster vaccine (Zostavax) is appropriate for immunocompromised patients—it is contraindicated 1

Infection Control

Patients with active herpes zoster should avoid contact with susceptible individuals (those who have not had chickenpox or vaccination) until all lesions have crusted. 1 This is particularly important for healthcare workers and childcare providers. 7 Patients are potentially contagious for at least 7-14 days from symptom onset in the second eye when involved. 7