What is the best treatment for a crusty cold sore?

Treatment for Crusty Cold Sores

Oral antiviral therapy, particularly valacyclovir 2g twice daily for 1 day, is the most effective treatment for crusty cold sores, reducing healing time and accelerating return to normal skin. 1, 2

First-Line Treatment Options

Oral Antivirals

Oral antivirals are the most effective treatment for cold sores, especially when started at the first sign of symptoms:

1. Valacyclovir:

   • Preferred regimen: 2g twice daily for 1 day 1, 2
   • Alternative: 2g twice daily on day 1, then 1g twice daily on day 2 1

2. Famciclovir:

   • 1500mg as a single dose 1
   • Alternative: 750mg twice daily for 1 day 1

3. Acyclovir:

   • 800mg 5 times daily for 5 days 1, 3

Topical Treatments

For patients who cannot take oral medications or prefer topical treatment:

1. Docosanol 10% cream (FDA-approved):

   • Apply 5 times daily until healed 4
   • Start at first sign of cold sore for best results
   • Less effective than oral antivirals but better than placebo 5

2. Acyclovir 5% cream:

   • Apply 5 times daily for 4 days 1
   • Modest effect on healing time 5

Supportive Care for Crusty Stage

1. Maintain moisture:

   • Apply white soft paraffin ointment to the lips every 2 hours 1
   • Prevents cracking and bleeding of crusted lesions

2. Pain management:

   • Benzydamine hydrochloride oral rinse/spray every 3 hours 1
   • For severe pain: topical lidocaine 2% 1

3. Prevent secondary infection:

   • Keep the area clean and dry 3
   • Consider antiseptic oral rinse twice daily (e.g., 0.2% chlorhexidine) 1

Treatment Algorithm Based on Cold Sore Stage

1. Prodromal stage (tingling, burning):

   • Immediate oral antiviral therapy (valacyclovir or famciclovir)
   • Apply docosanol if oral medication unavailable

2. Vesicular stage (blisters):

   • Oral antiviral therapy
   • Avoid touching or breaking blisters
   • Apply white soft paraffin for comfort

3. Crusting stage (current stage):

   • Continue antiviral if started early
   • Focus on moisturizing with white soft paraffin
   • Keep area clean to prevent secondary infection
   • Pain management as needed

4. Healing stage:

   • Continue moisturizing until completely healed
   • Protect from sun exposure with SPF 15+ 3

Important Considerations

• Timing is critical: Treatment efficacy decreases significantly if started more than 48 hours after symptom onset 3
• Avoid corticosteroids: Topical corticosteroids can potentiate HSV infection and should be avoided 3, 6
• Sun protection: Use sunscreen (SPF 15+) to prevent UV-triggered recurrences 3
• Monitor for complications: If lesions don't begin to resolve within 7-10 days, consider treatment failure or secondary infection 3

Special Populations

• Immunocompromised patients: Higher doses and longer treatment duration recommended (acyclovir 400mg five times daily for 7-10 days) 3
• Pregnant patients: Acyclovir 400mg orally three times daily for 5-7 days is considered safe 3

For crusty cold sores, the evidence strongly supports oral valacyclovir as the most effective treatment, with significant reduction in healing time and faster return to normal skin compared to other options.