What are the guidelines for managing shingles?

Management of Herpes Zoster (Shingles)

For immunocompetent adults with uncomplicated shingles, initiate oral valacyclovir 1 gram three times daily or famciclovir 500 mg three times daily within 72 hours of rash onset, continuing treatment until all lesions have completely scabbed—typically 7-10 days but potentially longer if new lesions continue to form. 1

Antiviral Therapy: First-Line Treatment

Timing and Initiation

• Treatment must begin within 72 hours of rash onset for optimal efficacy in reducing acute pain, accelerating lesion healing, and preventing postherpetic neuralgia 1, 2
• Therapy is most effective when started within 48 hours, though the 72-hour window remains the standard cutoff 1, 3
• Even if presenting after 72 hours, consider treatment in high-risk patients (immunocompromised, ophthalmic involvement, or severe disease) 1

Oral Antiviral Options for Immunocompetent Adults

Preferred regimens (superior bioavailability and dosing convenience):

• Valacyclovir 1 gram orally three times daily for 7-10 days 1, 3, 2
• Famciclovir 500 mg orally three times daily for 7-10 days 1, 2, 4

Alternative regimen (requires more frequent dosing):

• Acyclovir 800 mg orally five times daily for 7-10 days 1, 5, 6, 2, 4

Critical Treatment Endpoint

• Continue antiviral therapy until ALL lesions have completely scabbed, not just for an arbitrary 7-day period 1
• In immunocompetent patients, lesions typically continue erupting for 4-6 days with total disease duration of approximately 2 weeks 1
• Do not discontinue at exactly 7 days if lesions are still forming or have not completely scabbed 1
• Treatment duration may need extension beyond 7-10 days if active lesions persist 1

Intravenous Therapy: When to Escalate

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

• Disseminated herpes zoster (multi-dermatomal involvement, visceral involvement) 1, 5
• Severely immunocompromised patients 1, 5
• Complicated facial zoster with suspected CNS involvement 1
• Severe ophthalmic disease 1
• Patients unable to tolerate oral medications 1

Duration of IV therapy:

• Continue for minimum 7-10 days and until clinical resolution is attained 1
• Monitor renal function at initiation and once or twice weekly during treatment 1
• Dose adjustments required for renal impairment 1, 3

Special Populations

Immunocompromised Patients

• Initiate IV acyclovir 10 mg/kg every 8 hours immediately for any immunocompromised patient with shingles, particularly those on active chemotherapy or with conditions like multiple myeloma 1
• Consider temporary reduction in immunosuppressive medications in consultation with the treating specialist 1
• Immunocompromised patients may develop new lesions for 7-14 days and heal more slowly, requiring treatment extension well beyond standard duration 1
• Without adequate antiviral therapy, some develop chronic ulcerations with persistent viral replication 1
• High-dose IV acyclovir remains the treatment of choice for severely compromised hosts 1

Ophthalmic Involvement

• Any suspected ophthalmic zoster (V1 dermatome involvement, Hutchinson's sign) requires urgent ophthalmology referral 1, 7
• Initiate oral valacyclovir 1 gram three times daily or famciclovir 500 mg three times daily immediately 1
• Consider IV acyclovir for severe ophthalmic disease or CNS complications 1

Pregnant Women

• Varicella zoster immunoglobulin (VZIG) within 96 hours of exposure is recommended for varicella-susceptible pregnant women 1, 5
• If VZIG unavailable or >96 hours post-exposure, give 7-day course of oral acyclovir beginning 7-10 days after exposure 1
• For active shingles in pregnancy, oral acyclovir can be used though safety data remain limited 8

Renal Impairment

Dose adjustments are mandatory to prevent acute renal failure 1, 3:

• Valacyclovir dosing by creatinine clearance (CrCl):
  • CrCl 30-49 mL/min: 1 gram every 12 hours 3
  • CrCl 10-29 mL/min: 1 gram every 24 hours 3
  • CrCl <10 mL/min: 500 mg every 24 hours 3

Adjunctive Corticosteroid Therapy

Corticosteroids provide only modest benefits and carry significant risks:

• Prednisone may be used as adjunctive therapy in select cases of severe, widespread shingles in immunocompetent patients 1
• Typical regimen: Prednisone 40 mg daily, tapered over 3 weeks, added to standard antiviral therapy 9
• Evidence shows corticosteroids do NOT prevent postherpetic neuralgia despite reducing acute phase pain 9
• Avoid in immunocompromised patients due to increased risk of disseminated infection 1
• Contraindications: poorly controlled diabetes, history of steroid-induced psychosis, severe osteoporosis, prior severe steroid toxicity 1

The evidence from a high-quality randomized trial demonstrates that adding prednisolone to acyclovir confers only slight benefits over standard acyclovir therapy alone, with no reduction in postherpetic neuralgia frequency 9. Given the risks, particularly in elderly patients most susceptible to shingles, routine corticosteroid use is not recommended 1.

Prevention Strategies

Vaccination

• The recombinant zoster vaccine (Shingrix) is recommended for ALL adults aged ≥50 years, regardless of prior herpes zoster episodes 1
• Vaccination should ideally occur before initiating immunosuppressive therapies 1
• The vaccine can be considered after recovery from acute shingles to prevent future episodes 1
• Live-attenuated vaccine (Zostavax) is contraindicated in immunocompromised patients 1

Post-Exposure Prophylaxis

• VZIG (or IVIG) within 96 hours of exposure for varicella-susceptible patients exposed to active varicella zoster infection 1, 5
• If immunoglobulin unavailable or >96 hours post-exposure: 7-day course of oral acyclovir beginning 7-10 days after exposure 1

Prophylaxis in High-Risk Patients

• Acyclovir or valacyclovir prophylaxis recommended for patients receiving proteasome inhibitor-based therapies (e.g., bortezomib) 1
• Daily acyclovir 400 mg appears effective in myeloma patients 1

Infection Control

Patients with active shingles must avoid contact with susceptible individuals until all lesions have crusted 1:

• Lesions are contagious to individuals who have not had chickenpox 1
• Viral shedding peaks in the first 24 hours after lesion onset when most lesions are vesicular 1
• Healthcare workers and caregivers should use appropriate precautions 1

Common Pitfalls and Caveats

• Topical antiviral therapy is substantially less effective than systemic therapy and is NOT recommended 1, 5
• Do not use genital herpes dosing regimens (e.g., acyclovir 400 mg three times daily) for shingles—this is inadequate for VZV infection 1
• If lesions fail to resolve within 7-10 days, suspect acyclovir resistance: obtain viral culture with susceptibility testing 1
• For acyclovir-resistant cases, foscarnet 40 mg/kg IV every 8 hours is the treatment of choice 1, 5
• Monitor for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients receiving high-dose therapy 1
• Antiviral medications control symptoms and reduce complications but do not eradicate latent virus 1

Pain Management

Acute Phase Pain

• Antiviral therapy itself reduces acute pain duration and intensity when started early 2, 4
• Standard analgesics (acetaminophen, NSAIDs) for mild-to-moderate pain 7
• Opioids may be required for severe acute pain 7, 4

Postherpetic Neuralgia (PHN)

If pain persists >90 days after rash onset:

• Tricyclic antidepressants (e.g., amitriptyline) in low dosages for neuropathic pain control 7, 2
• Anticonvulsants (e.g., gabapentin, pregabalin) for neuropathic pain 7, 2
• Topical lidocaine patches for localized pain 7, 2
• Capsaicin cream in selected patients 7, 2
• Opioids for severe, refractory pain 7, 2
• Nerve blocks in selected cases 7

Valacyclovir and famciclovir have demonstrated superior efficacy in reducing PHN incidence compared to acyclovir, though none completely prevent this complication 2, 4.