What is the recommended treatment for a patient presenting with cold sores (herpes simplex labialis)?

Cold Sore Treatment

First-Line Treatment

Valacyclovir 2g twice daily for 1 day is the recommended first-line treatment for cold sores, which must be initiated within 24 hours of symptom onset—ideally during the prodromal stage (tingling, itching, burning)—to achieve maximum effectiveness. 1, 2

Oral Antiviral Options (in order of preference):

• Valacyclovir 2g twice daily for 1 day (doses taken 12 hours apart) reduces median episode duration by 1.0 day compared to placebo and offers the most convenient dosing schedule 1, 3
• Famciclovir 1500mg as a single dose is an equally effective alternative with single-day dosing, significantly reducing healing time 1, 4
• Acyclovir 400mg five times daily for 5 days is effective but requires more frequent dosing and lower patient adherence 1, 5

Critical Timing Considerations:

• Peak viral titers occur in the first 24 hours after lesion onset, making early intervention essential 1
• Treatment initiated after lesions have fully developed (papule, vesicle, or ulcer stage) has significantly reduced efficacy and has not been established as effective by FDA labeling 2
• Patient-initiated therapy at first symptoms may prevent lesion development entirely in some cases 4

Adjunctive Symptomatic Management

While oral antivirals are the cornerstone of treatment, these measures provide additional symptom relief:

• Apply white soft paraffin ointment to lips every 2 hours during acute illness for moisture barrier 1
• Topical anesthetics (benzydamine hydrochloride) can manage pain 1
• Antiseptic oral rinses (1.5% hydrogen peroxide or 0.2% chlorhexidine) reduce bacterial colonization 1

Important caveat: Topical antivirals provide only modest clinical benefit and are significantly less effective than oral therapy—they should not be used as monotherapy 1, 4

Suppressive Therapy for Frequent Recurrences

Consider daily suppressive therapy if patients experience 6 or more recurrences per year, as this reduces recurrence frequency by ≥75%. 1, 4

Suppressive Regimen Options:

• Valacyclovir 500mg once daily (can increase to 1000mg once daily for very frequent recurrences) 1, 4
• Famciclovir 250mg twice daily 4
• Acyclovir 400mg twice daily 4

Duration and Monitoring:

• Safety documented for acyclovir up to 6 years of continuous use 4
• Valacyclovir and famciclovir documented safe for 1 year of continuous use 4
• After 1 year of suppressive therapy, consider discontinuation to reassess recurrence rate, as frequency naturally decreases over time in many patients 4
• Topical antivirals are completely ineffective for suppression as they cannot reach the site of viral reactivation in sensory ganglia 1, 4

Special Populations: Immunocompromised Patients

Immunocompromised patients require special consideration:

• Episodes are typically longer, more severe, and may involve the oral cavity or extend across the face 1, 4
• Higher doses or longer treatment durations may be required 1, 4
• Acyclovir resistance rates are significantly higher (7% versus <0.5% in immunocompetent patients) 4
• For severe intraoral HSV or gingivostomatitis requiring hospitalization: acyclovir 5-10mg/kg IV every 8 hours until lesions regress, then switch to oral therapy 4
• For confirmed acyclovir-resistant HSV: foscarnet 40mg/kg IV three times daily is the treatment of choice 4

Preventive Counseling

Patients should be counseled on trigger avoidance:

• Apply sunscreen (SPF 15 or above) or zinc oxide to decrease UV light-triggered recurrences 1, 6
• Identify and avoid personal triggers including fever, psychological stress, and menstruation 1
• Avoid contact with lesions to prevent transmission to others 2

Common Pitfalls to Avoid

• Starting treatment too late: Efficacy decreases dramatically after the first 24 hours and is not established once ulcerative lesions have formed 1, 2
• Relying on topical antivirals: These are significantly inferior to oral therapy and should not be first-line 1, 4
• Failing to consider suppressive therapy: Patients with ≥6 recurrences per year could benefit substantially from daily suppression 1, 4
• Using topical antivirals for suppression: Completely ineffective as they cannot reach viral reservoirs in sensory ganglia 1, 4

Safety Profile

Oral antivirals are generally well-tolerated with minimal adverse events:

• Common side effects include headache (<10%), nausea (<4%), and mild gastrointestinal disturbances 1, 4
• Resistance development with episodic use in immunocompetent patients is rare (<0.5%) 1, 4
• Patients should maintain adequate hydration during treatment 2