Testing and Treatment of Herpes Simplex Virus (HSV)
For HSV infections, antiviral medications including valacyclovir, famciclovir, and acyclovir are the cornerstone of treatment, with specific regimens based on whether the infection is a first episode, recurrent episode, or requires suppressive therapy. 1
Diagnostic Testing
- Viral culture: Collect specimen from active lesions within 48 hours of appearance
- PCR testing: More sensitive than viral culture, especially for CSF or lesions that are healing
- Serologic testing: Can differentiate between HSV-1 and HSV-2 antibodies to confirm past infection
- Tzanck smear: Rapid but less sensitive test that can detect multinucleated giant cells
Treatment Options
First Episode Treatment
| Medication | Dosage |
|---|---|
| Valacyclovir | 1 gram twice daily for 7-10 days |
| Famciclovir | 250 mg three times daily for 7-10 days |
| Acyclovir | 400 mg three times daily for 7-10 days |
Recurrent Episode Treatment
| Medication | Dosage |
|---|---|
| Valacyclovir | 500 mg twice daily for 5-10 days or 1 gram twice daily for 1 day (for oral herpes) |
| Famciclovir | 125 mg twice daily for 5 days or 1000 mg twice daily for 1 day (for genital herpes) |
| Acyclovir | 400 mg three times daily for 5-10 days |
Suppressive Therapy
For patients with ≥6 recurrences per year or those who desire suppression:
| Medication | Dosage |
|---|---|
| Valacyclovir | 500-1000 mg once daily |
| Famciclovir | 250 mg twice daily |
| Acyclovir | 400 mg twice daily |
Special Populations
HIV-Infected Patients
- Require longer courses of therapy and closer monitoring 1
- For suppressive therapy: Valacyclovir 500 mg twice daily
Pregnant Patients
- Acyclovir is preferred due to established safety profile
Immunocompromised Patients
- Require longer treatment duration and closer monitoring
- Note: Famciclovir has not been established for immunocompromised patients other than HIV-infected patients with recurrent orolabial or genital herpes 2
Treatment Selection Considerations
- Convenience: Valacyclovir and famciclovir offer less frequent dosing (1-2 times daily) compared to acyclovir (3-5 times daily) 1, 3
- Bioavailability: Valacyclovir provides better oral bioavailability than acyclovir 3
- Efficacy: All three medications have comparable efficacy when used at appropriate doses 4, 5
Management of Resistant HSV
For acyclovir-resistant HSV (primarily in immunocompromised patients):
- Increase oral acyclovir to 800 mg five times daily
- If no response after 5-7 days, consider:
- Topical trifluridine for accessible lesions
- Intravenous foscarnet (40 mg/kg three times daily or 60 mg/kg twice daily) for 10 days 6
Prevention of Transmission
- Avoid direct contact with active lesions
- Use latex condoms during sexual activity
- Consider daily suppressive antiviral therapy for those with frequent recurrences
- Practice good hygiene, including regular handwashing 1
Pain Management
For pain associated with HSV infections:
- Mild pain: Acetaminophen or NSAIDs
- Moderate to severe pain: Consider gabapentin, pregabalin, or tricyclic antidepressants 1
Follow-up Recommendations
Patients should be re-examined 3-7 days after treatment initiation to:
- Assess treatment response
- Monitor for complete resolution of lesions
- Evaluate for signs of complications
- Ensure appropriate specialist referral if needed (e.g., ophthalmology for ocular involvement) 1
Common Pitfalls
- Delayed treatment: Antiviral therapy is most effective when started within 72 hours of symptom onset
- Inadequate dosing: Ensure proper dosage adjustments for patients with renal impairment 1, 2
- Failure to recognize resistance: Consider resistance in immunocompromised patients with poor response to standard therapy
- Insufficient patient education: Patients should understand the chronic nature of HSV and strategies to prevent transmission