What is the proper treatment for cold sores?

Treatment of Cold Sores (Herpes Labialis)

The most effective treatment for cold sores is oral valacyclovir 2 grams twice daily for one day, started at the first sign of symptoms, as it significantly reduces healing time and pain compared to other regimens. 1

First-Line Treatments

Oral Antiviral Therapy

• Valacyclovir (preferred):

  • 2 grams twice daily for 1 day, started at the earliest sign of cold sore (tingling, redness, itching) 1
  • Offers superior bioavailability compared to acyclovir, providing 3-5 times higher acyclovir concentrations
  • Reduces episode duration by approximately 1 day and accelerates healing 1

• Acyclovir (alternative):

  • 400 mg orally 3 times daily for 5 days, or
  • 200 mg orally 5 times daily for 5 days, or
  • 800 mg orally twice daily for 5 days 2
  • Most commonly prescribed antiviral for cold sores, though usage has decreased as newer options have emerged 3

• Famciclovir (alternative):

  • 500 mg orally twice daily for cold sores 2
  • No pediatric preparation exists, limiting use in children 2

Topical Antiviral Therapy

• Penciclovir cream (Denavir):

  • Apply every 2 hours during waking hours for 4 days 4
  • Start at earliest sign of cold sore for maximum effectiveness
  • Well-tolerated with minimal side effects 4

• Docosanol 10% cream (Abreva):

  • Apply 5 times daily until healed 5
  • Available over-the-counter
  • Apply at first sign of tingling for best results 5

Supportive Treatments

• Pain relief:

  • Acetaminophen or NSAIDs for pain management 2
  • NSAIDs provide significant benefits for headache and pain associated with cold sores 2

• Topical relief:

  • Salt water rinses or topical anesthetics may provide temporary relief
  • Avoid application near eyes due to risk of irritation 4

Treatment Algorithm Based on Severity

Mild Cold Sores

1. Start oral valacyclovir 2g twice daily for 1 day at first sign of symptoms
2. Apply topical antiviral (penciclovir or docosanol)
3. Use pain relievers as needed
4. Keep area clean and dry

Moderate to Severe Cold Sores

1. Oral valacyclovir 2g twice daily for 1 day
2. For extensive lesions or immunocompromised patients, consider extending treatment with acyclovir 400mg three times daily for 5-10 days 2
3. If lesions don't improve within 3-5 days, evaluate for secondary bacterial infection 4

For Recurrent Cold Sores (≥6 episodes per year)

Consider suppressive therapy:

• Valacyclovir 500mg daily (for <10 recurrences per year) or 1000mg daily (for ≥10 recurrences per year) 6
• Reduces recurrence frequency by ≥75% 6

Special Populations

Children

• For children ≥12 years: Same dosing as adults 7
• For children <12 years: Consult pediatrician (valacyclovir not FDA-approved for cold sores in this age group) 7

Pregnant Women

• Acyclovir is the preferred antiviral during pregnancy (Category B) 6
• Valacyclovir may be used if benefits outweigh risks 7
• A registry of 596 pregnant women exposed to acyclovir in first trimester showed no increased risk of birth defects 2

Important Clinical Pearls

• Timing is crucial: Treatment efficacy is highest when started during the prodromal phase (tingling, burning sensation) before visible lesions appear 6
• Patient education: Counsel patients about:
  • Viral transmission risk during active lesions
  • Need to avoid touching lesions and then touching other body parts
  • Importance of hand washing after touching lesions
  • Using separate towels and personal items during outbreaks 6
• Avoid triggers: Sun exposure, stress, and illness can trigger recurrences; sunscreen may help prevent UV-induced recurrences
• Treatment limitations: Antivirals reduce duration and severity but do not cure herpes infections 6

Cold sores typically resolve within 7-10 days even without treatment, but proper antiviral therapy can significantly reduce healing time, pain, and viral shedding when started promptly.

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