Should I treat Herpes Simplex Virus (HSV) if the lesion occurred more than 72 hours ago?

Treatment of HSV Lesions After 72 Hours

Antiviral treatment for HSV lesions is generally not recommended when initiated more than 72 hours after lesion onset, as efficacy has not been established beyond this timeframe. 1

Evidence-Based Rationale

The FDA-approved labeling for valacyclovir (Valtrex) clearly states that:

• For genital herpes initial episodes: "The efficacy of treatment with VALTREX when initiated more than 72 hours after the onset of signs and symptoms has not been established" 1
• For herpes zoster (shingles): "The efficacy of VALTREX when initiated more than 72 hours after the onset of rash... has not been established" 1

This 72-hour window is critical because:

1. Viral replication is most active during the first 72 hours
2. Antiviral medications work by inhibiting viral replication
3. Once viral replication has substantially decreased (after 72 hours), antivirals provide minimal benefit

Special Considerations

For Primary HSV Infections

• Primary infections tend to be more severe and prolonged
• All systemic symptoms (fever, malaise) must be resolved before return to activities 2
• No new lesions should have formed for at least 72 hours 2
• All existing lesions must be dry and covered by a firm, adherent crust 2

For Recurrent HSV Infections

• Lesions must be completely dry and covered by a firm, adherent crust 2
• Systemic antiviral therapy is typically recommended for at least 5 days during the active phase 2

Management Approach for Lesions >72 Hours Old

When a patient presents with HSV lesions that appeared more than 72 hours ago:

1. Assess lesion stage:

   • If lesions are still vesicular or ulcerative (not crusted), they may still be actively replicating virus
   • If lesions are already crusting/healing, viral replication has likely ceased

2. Evaluate for complications:

   • Secondary bacterial infection
   • Extensive or disseminated disease
   • Immunocompromised status
   • Severe pain

3. Supportive care measures:

   • Keep lesions clean and dry
   • Use mild soap and water for cleansing
   • Apply petroleum jelly to prevent cracking of crusts
   • Use acetaminophen or NSAIDs for pain relief

Common Pitfalls to Avoid

1. Starting antivirals too late: Initiating treatment after 72 hours provides minimal benefit for typical cases

2. Failing to recognize exceptions: Consider treatment regardless of timing in:

   • Immunocompromised patients
   • Severe or disseminated disease
   • Ophthalmic involvement

3. Overlooking prevention: For patients with recurrent HSV, discuss suppressive therapy to prevent future outbreaks

Conclusion for Clinical Practice

For HSV lesions present for more than 72 hours:

• Focus on supportive care rather than antiviral therapy
• Reserve antiviral treatment for special circumstances (immunocompromised patients, severe disease)
• Consider prophylactic antivirals for patients with frequent recurrences