What is the appropriate treatment for a typical adult with recurrent herpes labialis (cold sores)?

Treatment of Herpes Labialis (Cold Sores)

For episodic treatment of recurrent herpes labialis in adults, initiate valacyclovir 2 g twice daily for 1 day (doses separated by 12 hours) at the first sign of prodromal symptoms (tingling, itching, burning) or within 24 hours of lesion onset. 1

First-Line Episodic Treatment Options

Oral antiviral therapy is superior to topical treatments and should be the standard approach. 1 The three evidence-based regimens are:

• Valacyclovir 2 g twice daily for 1 day (12 hours apart) – reduces median episode duration by 1.0 day compared to placebo, with high-quality evidence supporting this as first-line therapy 1
• Famciclovir 1500 mg as a single dose – equally effective alternative with the convenience of single-day dosing 1, 2, 3
• Acyclovir 400 mg five times daily for 5 days – effective but requires more frequent dosing, which may reduce adherence 1

The short-course, high-dose regimens (valacyclovir and famciclovir) offer greater convenience, lower cost, and improved adherence compared to traditional longer courses. 1

Critical Timing Considerations

Treatment must be initiated during the prodromal phase or within 24 hours of lesion onset to achieve optimal benefit. 1 Peak viral titers occur in the first 24 hours after lesion appearance, making early viral replication blockade essential. 1 Efficacy decreases significantly when treatment starts after lesions have fully developed. 1

Provide patients with a prescription to keep on hand so treatment can be initiated immediately at first symptoms. 1

Suppressive Therapy for Frequent Recurrences

Consider daily suppressive therapy for patients experiencing six or more recurrences per year. 1 Suppressive therapy reduces recurrence frequency by ≥75%. 1

First-line suppressive options include:

• Valacyclovir 500 mg once daily (can increase to 1000 mg once daily for very frequent recurrences) 1
• Famciclovir 250 mg twice daily 1
• Acyclovir 400 mg twice daily 1

Safety and efficacy have been documented for acyclovir for up to 6 years, while valacyclovir and famciclovir have documented safety for 1 year of continuous use. 1 After 1 year of continuous suppressive therapy, consider discontinuation to reassess the patient's recurrence rate, as frequency decreases over time in many patients. 1

Topical Therapy: Limited Role

Topical antivirals provide only modest clinical benefit (approximately 1-day reduction in symptoms) and are substantially less effective than oral therapy. 1, 4 Topical agents cannot reach the site of viral reactivation in neurons and are not effective for prophylaxis. 1, 4

If topical therapy is used despite its limitations, penciclovir 1% cream is FDA-approved for herpes labialis in adults and children ≥12 years. 5 However, oral therapy remains the preferred approach. 1

Common Pitfalls to Avoid

• Relying solely on topical treatments when oral therapy is more effective 1
• Starting treatment too late – efficacy decreases significantly after the first 24 hours 1
• Failing to consider suppressive therapy in patients with ≥6 recurrences per year who could significantly benefit 1
• Using inadequate dosing – short-course, high-dose therapy is more effective than traditional longer courses 1

Preventive Counseling

Counsel patients to identify and avoid personal triggers, including:

• Ultraviolet light exposure – applying sunscreen (SPF ≥15) or zinc oxide before sun exposure can prevent UV-triggered recurrences 1
• Fever, psychological stress, and menstruation – common triggers that should be discussed 1

Special Populations

Immunocompromised patients typically experience longer and more severe episodes, potentially involving the oral cavity or extending across the face. 1 They may require higher doses or longer treatment durations, and have higher acyclovir resistance rates (7% versus <0.5% in immunocompetent patients). 1

For confirmed acyclovir-resistant HSV, foscarnet 40 mg/kg IV three times daily is the treatment of choice. 1

Antiviral Resistance

Despite increasing use of HSV-specific antiviral agents, the incidence of resistant HSV-1 strains remains low (<0.5% in immunocompetent hosts). 1 Development of resistance when oral antivirals are used episodically in immunocompetent patients is unlikely to occur. 1

Adjunctive Supportive Care

• White soft paraffin ointment applied to lips every 2 hours for moisture and protection 4
• Topical anesthetics (e.g., viscous lidocaine 2%) for pain control if needed 4
• Topical antiseptics to reduce bacterial colonization 4

Avoid topical corticosteroids alone for HSV labialis, as they potentiate HSV epithelial infections unless combined with antiviral therapy. 4