What is the recommended workup and treatment for shingles?

Workup and Treatment of Shingles (Herpes Zoster)

Diagnostic Approach

Clinical diagnosis is sufficient for most immunocompetent patients with typical dermatomal vesicular rash, but laboratory confirmation is needed for immunocompromised patients or atypical presentations. 1

• Typical presentation: Unilateral dermatomal vesicular rash with burning pain that typically precedes the rash by several days 2
• Laboratory confirmation required when:
  • Immunocompromised patients with atypical presentation 1
  • Uncertain diagnosis 1
  • Gold standard testing: PCR and direct identification of VZV in cell cultures 3
  • Detection of IgM- and IgA-anti VZV antibodies may be helpful in immunocompromised patients 3

Treatment: Antiviral Therapy

Immunocompetent Patients with Uncomplicated Shingles

Initiate oral antiviral therapy within 72 hours of rash onset (ideally within 48 hours) and continue until all lesions have scabbed. 1, 4

First-line oral antiviral options:

• Valacyclovir 1 gram three times daily 1, 4
• Acyclovir 800 mg five times daily 1, 5
• Famciclovir 500 mg three times daily (higher VZV-appropriate doses) 1

Key treatment principles:

• Valacyclovir and famciclovir offer better bioavailability and more convenient dosing (three times daily) compared to acyclovir (five times daily) 1, 6
• Treatment duration: 7-10 days, but continue until all lesions have completely scabbed—this is the key clinical endpoint, not an arbitrary 7-day duration 1, 4
• Treatment is most effective within 48-72 hours of rash onset, but evidence suggests benefit even when started later 7
• Topical antiviral therapy is substantially less effective than systemic therapy and is not recommended 1, 5

Immunocompromised Patients or Severe Disease

Intravenous acyclovir is required for disseminated, invasive, or severe herpes zoster in immunocompromised patients. 1

Indications for IV acyclovir:

• Disseminated herpes zoster (multi-dermatomal, visceral involvement) 1
• Immunocompromised patients (e.g., HIV, chemotherapy, transplant recipients) 1
• Complicated facial zoster with suspected CNS involvement 1
• Severe ophthalmic disease 1

IV acyclovir dosing:

• 10 mg/kg every 8 hours for severely immunocompromised hosts 1
• Continue for minimum 7-10 days and until clinical resolution 1
• Monitor renal function closely with dose adjustments as needed for renal impairment 1
• Assess for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients receiving high-dose therapy 1

Additional management for immunocompromised patients:

• Consider temporary reduction in immunosuppressive medications for disseminated or invasive disease 1
• Kidney transplant recipients with uncomplicated herpes zoster can receive oral acyclovir or valacyclovir 1

Special Populations and Situations

Facial/Ophthalmic Zoster:

• Urgent indication for systemic antiviral therapy due to risk of ophthalmic and cranial nerve complications 1, 3
• Initiate oral valacyclovir 1 gram three times daily or famciclovir 500 mg three times daily within 72 hours 1
• Consider IV therapy if CNS involvement suspected 1
• Elevation of affected area to promote drainage and keeping skin well hydrated with emollients is recommended 1
• Generally merits referral to ophthalmologist for ocular involvement 2

Pregnant Women:

• VZIG (varicella zoster immune globulin) is recommended for VZV-susceptible pregnant women within 96 hours after exposure to VZV 5
• If oral acyclovir is used, VZV serology should be performed to determine if patient is already seropositive 5

Acyclovir-Resistant Cases:

• Suspect resistance if lesions do not begin to resolve within 7-10 days of therapy 8
• Foscarnet 40 mg/kg IV every 8 hours or cidofovir for proven or suspected resistance 8, 5

Pain Management

Adequate pain control is the most important aim of herpes zoster therapy, requiring a multimodal approach. 3

Acute pain management:

• Appropriately dosed analgesics in combination with neuroactive agents (e.g., amitriptyline) given together with antiviral therapy 3
• Narcotics may be required for adequate pain control 2

Postherpetic neuralgia (if pain persists beyond rash resolution):

• Tricyclic antidepressants or anticonvulsants in low dosages to control neuropathic pain 2
• Capsaicin, lidocaine patches, and nerve blocks in selected patients 2
• Early presentation to pain therapist recommended in specific cases 3

Role of Corticosteroids

Corticosteroids may provide modest benefits in reducing acute pain but do not prevent postherpetic neuralgia and carry significant risks. 9

• Prednisone may be used as adjunctive therapy to antivirals in select cases of severe, widespread shingles 1
• Avoid in immunocompromised patients due to increased risk of disseminated infection 1
• Contraindications: Poorly controlled diabetes, history of steroid-induced psychosis, severe osteoporosis, or prior severe steroid toxicity 1
• A 21-day course of acyclovir or addition of prednisolone confers only slight benefits over standard 7-day acyclovir treatment and does not reduce frequency of postherpetic neuralgia 9

Infection Control

Patients with shingles should avoid contact with susceptible individuals until all lesions have crusted, as 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

Prevention

The recombinant zoster vaccine (Shingrix) is recommended for all adults aged 50 years and older, regardless of prior herpes zoster episodes. 1

• Vaccination should ideally occur before initiating immunosuppressive therapies 1
• Can be considered after recovery to prevent future episodes 1

Common Pitfalls

• Do not rely on arbitrary 7-day treatment duration—continue antivirals until all lesions have scabbed 1
• Do not use topical acyclovir—it is substantially less effective than systemic therapy 1, 5
• Do not delay treatment beyond 72 hours when possible, though benefit may still occur with later initiation 7
• Do not underestimate severity in immunocompromised patients—have low threshold for IV therapy 1
• Do not use valacyclovir 8 grams per day in immunocompromised patients due to risk of hemolytic uremic syndrome/thrombotic thrombocytopenic purpura 8