What is the recommended treatment for cold sores (herpes simplex labialis)?

Cold Sore Treatment Recommendations

For cold sores (herpes simplex labialis), the recommended first-line treatment is valacyclovir 2g twice daily for one day, initiated at the earliest symptom onset for maximum effectiveness. 1, 2

Antiviral Therapy Options

First-Line Treatment

• Valacyclovir (preferred):
  • 2g twice daily for 1 day (total of 2 doses taken 12 hours apart) 1, 2
  • Must be initiated at earliest symptoms (tingling, itching, burning) 1
  • Treatment should not exceed 1 day (2 doses) 1
  • Better absorbed than acyclovir with 3-5 times higher bioavailability 2

Alternative Options

• Acyclovir:

  • 800mg orally, five times daily for 7-10 days 3
  • Less convenient dosing schedule compared to valacyclovir

• Famciclovir:

  • 500mg three times daily for 7 days 3

Treatment Timing and Efficacy

• Critical timing: Treatment must be initiated at the earliest symptoms (tingling, itching, burning) and before development of visible lesions (papule, vesicle, or ulcer) 1
• Efficacy evidence:
  • Valacyclovir reduces episode duration by approximately 1 day compared to placebo 2
  • Early treatment (within 24-48 hours of symptom onset) correlates with better outcomes 3
  • Treatment initiated after lesion development has not been established as effective 1

Special Populations

• Immunocompromised patients:

  • Higher doses of acyclovir (400mg five times daily)
  • Longer treatment duration (7-10 days)
  • IV acyclovir 5-10mg/kg every 8 hours for severe cases 3

• Pregnant patients:

  • Acyclovir 400mg orally three times daily for 5-7 days OR
  • Acyclovir 200mg orally five times daily for 5-7 days 3

Supportive Care

• Pain management: Acetaminophen or other analgesics based on pain severity 3
• Topical relief options: Mixture of Maalox and diphenhydramine or viscous lidocaine (use with caution in young children) 3
• Hydration: Maintain adequate hydration throughout treatment 1
• Prevention of secondary infection: Keep the area clean and dry 3

Prevention of Recurrence

• Avoid triggers: UV radiation, fever, psychological stress, and local trauma 3
• Sun protection: Use sunscreen (SPF 15 or above) to prevent UV-triggered recurrences 3

Important Caveats

• Valacyclovir is not a cure for cold sores 1
• Treatment efficacy decreases significantly if not started early
• Topical treatments like penciclovir cream may be an alternative but are generally less effective than oral antivirals 4
• For recurrent episodes, patients should be instructed to keep medication on hand to initiate treatment immediately upon first symptoms 1
• Patients should be advised about the contagious nature of cold sores to prevent transmission 5

Treatment Algorithm

1. Assess timing: If within early symptom onset (tingling/burning/itching), proceed with treatment
2. First choice: Valacyclovir 2g twice daily for 1 day
3. If valacyclovir unavailable: Acyclovir 800mg five times daily for 7-10 days
4. For immunocompromised patients: Higher doses and longer duration as specified above
5. Add supportive care: Pain management, hydration, and prevention measures