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

Treatment of Cold Sores (Herpes Labialis)

Valacyclovir 2g twice daily for 1 day is the first-line treatment for cold sores, initiated within 24 hours of symptom onset—ideally during the prodromal stage when patients first experience tingling, itching, or burning. 1, 2

Acute Episode Treatment

First-Line Oral Antiviral Therapy

• Valacyclovir 2g twice daily for 1 day is the preferred regimen, reducing median episode duration by 1.0 day compared to placebo 1, 3
• This single-day regimen offers superior convenience and may improve adherence compared to longer courses 1
• FDA-approved for cold sores in adults and children ≥12 years 2

Alternative Oral Regimens

• Famciclovir 1500mg as a single dose is equally effective, significantly reducing healing time of primary lesions 1, 4
• Acyclovir 400mg five times daily for 5 days is another option but requires more frequent dosing and longer treatment duration 1, 5
• All three oral antivirals are generally well-tolerated with minimal adverse events (headache <10%, nausea <4%, mild GI disturbances) 1

Critical Timing Considerations

• Treatment must begin within 24 hours of symptom onset for maximum effectiveness 1, 5
• Peak viral titers occur in the first 24 hours after lesion onset, making early intervention essential 1
• Patient-initiated therapy at first symptoms may prevent lesion development in some cases 6
• Efficacy decreases significantly when treatment is initiated after lesions have fully developed 1, 6

Topical and Adjunctive Therapy

• Topical antivirals provide only modest clinical benefit and are less effective than oral therapy 1, 5
• Apply white soft paraffin ointment to the lips every 2 hours throughout acute illness for symptomatic relief 1
• Topical anesthetics (e.g., benzydamine hydrochloride) can help manage pain 1
• Antiseptic oral rinses (1.5% hydrogen peroxide or 0.2% chlorhexidine digluconate) can reduce bacterial colonization 1

Suppressive Therapy for Frequent Recurrences

Indications

• Consider suppressive therapy if experiencing ≥6 recurrences per year 1, 6
• Also indicated for patients with particularly severe, frequent, or complicated disease 6
• Patients with significant psychological distress from recurrences are candidates 6

Suppressive Regimens

• Valacyclovir 500mg once daily is first-line suppressive therapy, which can increase to 1000mg once daily for very frequent recurrences 1, 6
• Famciclovir 250mg twice daily is an alternative 6
• Acyclovir 400mg twice daily is another option 6
• Daily suppressive therapy reduces recurrence frequency by ≥75% 1, 6

Duration and Monitoring

• Safety and efficacy documented for acyclovir up to 6 years 6
• Valacyclovir and famciclovir have documented safety for 1 year of continuous use 6
• After 1 year of continuous suppressive therapy, consider discontinuation to reassess recurrence rate, as frequency decreases over time in many patients 6
• Topical antivirals are NOT effective for suppressive therapy as they cannot reach the site of viral reactivation 1, 6

Special Populations

Immunocompromised Patients

• Episodes are typically longer and more severe, potentially involving the oral cavity or extending across the face 6
• Higher doses or longer treatment durations may be required 1, 6
• Resistance rates to acyclovir are higher (7% vs. <0.5% in immunocompetent patients) 6
• For confirmed acyclovir-resistant HSV, IV foscarnet 40mg/kg three times daily is the treatment of choice 6

Preventive Measures

• Identify and avoid personal triggers including ultraviolet light exposure, fever, psychological stress, and menstruation 1, 6
• Use sunscreen or zinc oxide to decrease the probability of recurrent outbreaks 1
• Discuss trigger avoidance even while on suppressive therapy 6

Common Pitfalls to Avoid

• Do not rely solely on topical treatments when oral therapy is significantly more effective 1, 6
• Do not start treatment too late—efficacy plummets after lesions fully develop 1, 6
• Do not use topical antivirals for suppressive therapy—they cannot reach viral reactivation sites 1, 6
• Do not fail to consider suppressive therapy in patients with ≥6 recurrences per year who could benefit substantially 6
• Do not use inadequate dosing—short-course, high-dose therapy is more effective than traditional longer courses 6
• Development of resistance with episodic use in immunocompetent patients is rare (<0.5%) 1, 6