What is the treatment for cold sores?

Cold Sore Treatment

For acute cold sore episodes, initiate valacyclovir 2g twice daily for 1 day at the first sign of symptoms (prodrome, tingling, or redness) for maximum effectiveness. 1, 2

First-Line Oral Antiviral Treatment

Oral antivirals are significantly more effective than topical treatments and should be the primary therapeutic approach. 1, 2

Recommended Regimens (in order of preference):

• Valacyclovir 2g twice daily for 1 day - This high-dose, short-course regimen reduces median episode duration by 1.0 day compared to placebo and offers superior convenience and adherence 1, 3

• Famciclovir 1500mg as a single dose - Highly effective alternative that significantly reduces healing time of primary lesions 1, 2

• Acyclovir 400mg five times daily for 5 days - Effective but requires more frequent dosing, making it less convenient than the above options 1, 2

Critical Timing Considerations:

• Treatment must be initiated within 24 hours of symptom onset, ideally during the prodromal stage (tingling, itching, burning) before visible lesions appear 1, 2

• Peak viral titers occur in the first 24 hours after lesion onset, making early intervention essential for therapeutic benefit 4, 2

• Efficacy decreases significantly when treatment starts after lesions have fully developed 1, 2

• Patient-initiated episodic therapy at first symptoms may even prevent lesion development in some cases 1

Topical Treatment Options (Adjunctive Only)

Topical antivirals provide only modest clinical benefit and should not replace oral therapy. 1, 2

• Penciclovir 1% cream applied every 2 hours while awake for 4 days reduces healing time by 0.7 days but is substantially less effective than oral antivirals 5, 6

• Topical acyclovir provides minimal benefit and its use is generally discouraged compared to systemic therapy 4

• White soft paraffin ointment applied every 2 hours can provide symptomatic relief 2

• Topical anesthetics (benzydamine hydrochloride) may help manage pain 2

Suppressive Therapy for Frequent Recurrences

Consider daily suppressive therapy if experiencing 6 or more recurrences per year. 1, 2

Suppressive Regimens:

• Valacyclovir 500mg once daily (can increase to 1000mg once daily for very frequent recurrences) 1

• Famciclovir 250mg twice daily 1

• Acyclovir 400mg twice daily 1

Efficacy and Duration:

• Daily suppressive therapy reduces recurrence frequency by ≥75% among patients with frequent outbreaks 1

• Safety and efficacy documented for acyclovir up to 6 years; valacyclovir and famciclovir documented for 1 year of continuous use 1

• After 1 year of continuous suppressive therapy, consider discontinuation to reassess recurrence rate, as frequency decreases over time in many patients 1

Important Limitations:

• Topical antivirals are completely ineffective for suppressive therapy as they cannot reach the site of viral reactivation in the sensory ganglia 4, 1, 2

• Suppressive therapy reduces but does not eliminate asymptomatic viral shedding 1

Special Populations

Immunocompromised Patients:

• May require higher doses or longer treatment durations 1, 2

• Episodes are typically longer and more severe, potentially involving the oral cavity or extending across the face 4

• Acyclovir resistance rates up to 7% in this population (compared to <0.5% in immunocompetent patients) 1

Pediatric Patients:

• Valacyclovir is FDA-approved for cold sores in patients ≥12 years of age 7

• Use the same adult dosing regimen (2g twice daily for 1 day) for adolescents ≥12 years 7

Pregnancy and Lactation:

• Valacyclovir: Major birth defects during first-trimester exposure was 4.5%, though available studies have methodological limitations 7

• Acyclovir (valacyclovir's metabolite) is present in breast milk; a 500mg maternal dose twice daily provides approximately 0.6 mg/kg/day to the breastfed infant 7

• Consider risk-benefit ratio given the self-limiting nature of cold sores 7

Safety Profile

• All oral antivirals (acyclovir, valacyclovir, famciclovir) are generally well-tolerated with minimal adverse events 1, 2

• Common side effects include headache (<10%), nausea (<4%), and diarrhea, which are typically mild to moderate 1

• Development of resistance to oral antivirals when used episodically in immunocompetent patients is rare (<0.5%) 1, 2

Preventive Measures

• Apply sunscreen or zinc oxide to lips before UV light exposure to decrease recurrence probability 4, 2

• Identify and avoid personal triggers: stress, fever, menstruation, psychological stress 4, 2

• Maintain good hygiene to prevent transmission to others or autoinoculation 2

Common Pitfalls to Avoid

• Relying solely on topical treatments when oral therapy is significantly more effective - This is the most common error in cold sore management 1, 2

• Starting treatment too late - Waiting until lesions are fully developed dramatically reduces therapeutic benefit 1, 2

• Using topical antivirals for suppressive therapy - These cannot reach the site of viral reactivation and are completely ineffective for prevention 4, 1, 2

• Failing to consider suppressive therapy in patients with ≥6 recurrences per year who could benefit from 75% reduction in outbreak frequency 1

• Inadequate dosing - Not using the short-course, high-dose regimens that are more effective than traditional longer courses 1

• Applying treatment near or in the eyes - Penciclovir cream may cause irritation and should only be used on lips and face 5