Treatment of Varicella-Zoster Infection (Shingles)
For herpes zoster (shingles), start oral acyclovir, valacyclovir, or famciclovir within 72 hours of rash onset in all patients over 50 years old, immunocompromised patients, and those with moderate-to-severe disease; use intravenous acyclovir for immunocompromised patients with disseminated disease or severe immunosuppression.
Healthy Adults
For immunocompetent adults with herpes zoster, oral antiviral therapy is effective when initiated within 72 hours of rash onset. Acyclovir and famciclovir are FDA-approved for treating herpes zoster and accelerate cutaneous healing while reducing acute pain severity 1. Valacyclovir has similar efficacy 1.
Treatment is particularly important for:
- Adults over 50 years of age
- Patients with moderate-to-severe pain
- Patients with moderate-to-severe rash
- Those with herpes zoster ophthalmicus 2
The goal is to reduce acute pain, accelerate healing, and prevent postherpetic neuralgia, which occurs in 10-30% of cases and represents the most debilitating complication 3.
Immunocompromised Patients
High-dose intravenous acyclovir remains the treatment of choice for VZV infections in immunocompromised hosts 4. This population faces substantially higher risks:
- 25-45% of chemotherapy patients, HSCT recipients, and solid organ transplant recipients develop dermatomal zoster
- 10-20% risk of dissemination without prompt antiviral therapy
- Risk of chronic ulcerations with persistent viral replication 4
Treatment Algorithm for Immunocompromised Patients:
Use IV acyclovir for:
- Disseminated VZV infection
- Ophthalmic involvement
- Very severe immunosuppression
- Inability to take oral medications 5
Oral therapy (valacyclovir, famciclovir, or acyclovir) may be used for:
- Localized disease with close outpatient follow-up
- Mild cases in patients with transient immunosuppression
- Completion therapy after clinical response to IV acyclovir 4, 5
Critical timing: Initiate antiviral therapy if presentation occurs within 1 week of rash onset or any time before full crusting of lesions 5.
For acyclovir-resistant strains (which occur in immunocompromised patients), foscarnet is the drug of choice 5, 6. Cidofovir is an alternative 7.
Pregnant Women
For pregnant women with serious VZV complications such as pneumonia, intravenous acyclovir should be used 1. While acyclovir is FDA Category B and a prospective registry of 596 first-trimester exposures showed no increased birth defects 1, routine oral acyclovir is not recommended for uncomplicated cases because risks and benefits to the fetus were not fully established in the available guidelines.
For VZV-susceptible pregnant women exposed to varicella or zoster, administer varicella zoster immune globulin (VZIG) within 96 hours of exposure 7, 8, 7.
Children
Immunocompetent Children:
Oral acyclovir is not routinely recommended for healthy children with varicella 1. The American Academy of Pediatrics concluded that clinical benefits do not justify routine administration in this population.
Consider oral acyclovir for children at increased risk:
- Age >12 years
- Chronic cutaneous or pulmonary disorders
- Long-term salicylate therapy
- Short, intermittent, or aerosolized corticosteroid courses 1
Immunocompromised Children:
Intravenous acyclovir is essential when administered within 24 hours of rash onset, as it effectively reduces varicella-associated morbidity and mortality 1.
Use IV acyclovir for:
- Children with altered cell-mediated immunity
- Newborns during first 2 weeks of life
- Preterm infants in neonatal nursery
- Severe varicella or shingles in any child
- Children younger than 2 years of age with disease requiring treatment 9
Special Pediatric Considerations:
For newborns whose mothers developed chickenpox 5 days before to 2 days after delivery, consider VZV immunoglobulin treatment 10.
Common Pitfalls to Avoid
Timing is critical: Antivirals must be started within 72 hours of rash onset for herpes zoster (within 24 hours for varicella in high-risk patients) to be maximally effective 1, 5.
Don't use oral therapy as first-line in severely immunocompromised patients: This population requires IV acyclovir initially due to risk of dissemination 4, 5.
Consider resistance in transplant recipients: Patients already taking acyclovir prophylaxis (800 mg bid) or valacyclovir (500 mg bid) who develop breakthrough lesions may harbor resistant strains requiring foscarnet 4.
Acyclovir is not indicated for prophylaxis in otherwise healthy individuals after varicella exposure—vaccination is preferred 1.
Pain management is essential: Combine appropriate analgesic therapy with early antiviral treatment to reduce acute zoster pain and postherpetic neuralgia 5.