What is the treatment for cold sores?

Treatment of Cold Sores (Herpes Labialis)

Oral antiviral medications, particularly valacyclovir 2g twice daily for 1 day, are the most effective treatment for cold sores, significantly reducing healing time and symptom duration compared to placebo or topical treatments. 1

First-Line Treatment Options

Oral Antiviral Medications

• Valacyclovir: 2g twice daily for 1 day (preferred regimen)

  • Reduces median episode duration by 1.0-1.3 days compared to placebo 1
  • High-dose, short-duration therapy has been shown to be both effective and convenient 2

• Famciclovir: 1500mg as a single dose

  • Reduces median time to healing by 1.8 days (4.4 days vs 6.2 days with placebo) 1

• Acyclovir: 200mg 5 times daily for 5-7 days

  • Particularly recommended during pregnancy due to its established safety profile 1
  • Reduces duration of symptoms (8.1 days vs 12.5 days) and pain duration (2.5 days vs 3.9 days) compared to placebo 1

Critical Timing of Treatment

Treatment should be initiated within the first 24-48 hours of symptom onset for maximum efficacy 1. This is crucial because:

• Peak viral titers occur in the first 24 hours after lesion onset 3
• Natural healing process starts within the first 24 hours of onset 3
• Efficacy of valacyclovir initiated after development of clinical signs has not been established 1

Topical Treatment Options

• Topical acyclovir 5% cream: Less effective than oral therapy but may provide some benefit if applied early 1

• Penciclovir (Denavir) cream: Apply every 2 hours during waking hours for 4 days

  • Should be started at the earliest sign of a cold sore (tingling, redness, itching, or bump) 4
  • Common side effects include application site reactions, local anesthesia, taste perversion, and rash 4

Special Populations

Pregnancy

• Acyclovir (200mg 5 times daily for 5-7 days) is the preferred treatment during pregnancy 1
• Valacyclovir has limited safety data in pregnancy, with a 4.5% occurrence of major birth defects during first-trimester exposure (95% CI: 0.24% to 24.9%) 5

Immunocompromised Patients

• Higher doses of acyclovir (400mg five times daily) and longer treatment duration (7-10 days) may be needed 1
• Episodes are usually longer and more severe, potentially involving the oral cavity or extending across the face 3
• Consider hospitalization if severe symptoms or dissemination occur 1

Preventive Measures

• Apply sunscreen (SPF 15 or above) to help prevent UV-induced recurrences 1
• Avoid known triggers: UV radiation, fever, psychological stress, and menstruation 3
• For patients with frequent recurrences (>6 episodes/year), consider suppressive therapy:
  • Acyclovir 400mg twice daily or valacyclovir 500-2000mg twice daily 1

Treatment Algorithm

1. Prodromal phase (tingling, burning, itching):

   • Start oral antiviral immediately (valacyclovir 2g twice daily for 1 day)
   • Apply topical treatment if oral medication is unavailable

2. Vesicular phase:

   • Continue oral antiviral if started during prodrome
   • If not yet treated, start oral antiviral immediately
   • Consider topical anesthetics for pain relief

3. Crusting/healing phase:

   • Complete prescribed course of medication
   • Keep area clean and dry to prevent secondary infection

Common Pitfalls to Avoid

• Delayed treatment: Efficacy significantly decreases if treatment is initiated after 48 hours
• Inadequate dosing: Follow recommended high-dose, short-duration regimens for oral antivirals
• Ignoring preventive measures: Counsel patients about avoiding triggers and using sunscreen
• Applying topical treatments to mucous membranes: Penciclovir should only be used on herpes labialis on the lips and face, not on mucous membranes 4
• Missing secondary bacterial infections: Lesions that do not improve or worsen on therapy should be evaluated for secondary bacterial infection 4