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

Treatment of Cold Sores in Children

For children ≥12 years with cold sores, initiate valacyclovir 2 grams twice daily for 1 day (12 hours apart) at the earliest symptom of tingling, itching, or burning. 1

First-Line Treatment by Age

Children ≥12 Years

• Valacyclovir 2g twice daily for 1 day is the FDA-approved first-line treatment, offering the most convenient dosing with proven efficacy 1
• Treatment must be initiated within 24 hours of symptom onset, ideally during the prodromal stage (tingling, itching, burning) before visible lesions appear 2, 3
• This regimen reduces median episode duration by approximately 1 day compared to placebo 2, 4
• Peak viral titers occur in the first 24 hours after lesion onset, making early intervention critical for blocking viral replication 2, 3

Children <12 Years

• No FDA-approved oral antiviral therapy exists for cold sores in children under 12 years 1
• Valacyclovir oral suspension (25 mg/mL or 50 mg/mL) can be prepared extemporaneously from 500-mg tablets for pediatric patients when solid dosage forms are inappropriate, though this is not specifically FDA-approved for cold sores in this age group 1
• Supportive care with white soft paraffin ointment applied every 2 hours throughout acute illness can provide symptomatic relief 3
• Topical anesthetics (benzydamine hydrochloride) may help manage pain 3

Alternative Oral Antiviral Options (Age ≥12 Years)

• Famciclovir 1500mg as a single dose is an effective alternative, significantly reducing healing time 2, 3
• Acyclovir 400mg five times daily for 5 days is another option but requires more frequent dosing and is less convenient 2, 3

Management of Frequent Recurrences (≥6 Episodes/Year)

Consider suppressive therapy if the child experiences six or more recurrences per year. 2, 5

Suppressive Therapy Options

• Valacyclovir 500mg once daily (can increase to 1000mg once daily for very frequent recurrences) 2, 5
• Acyclovir 400mg twice daily 2, 5
• Daily suppressive therapy reduces recurrence frequency by ≥75% 2, 3
• Safety and efficacy documented for acyclovir up to 6 years; valacyclovir documented for 1 year of continuous use 2
• After 1 year of continuous suppressive therapy, consider discontinuation to reassess recurrence rate, as frequency decreases over time in many patients 2

Why Topical Treatments Are Inadequate

• Topical antivirals provide only modest clinical benefit and are significantly less effective than oral therapy 2, 3
• Topical antivirals are completely ineffective for suppressive therapy because they cannot reach the site of viral reactivation in sensory ganglia 2, 3, 5
• Topical treatments may be used adjunctively for symptom relief but should never replace oral antivirals when indicated 3

Safety Profile in Children

• Oral antivirals are generally well-tolerated in children with minimal adverse events 5
• Common side effects include headache, nausea, and mild gastrointestinal disturbances, typically mild to moderate in intensity 2, 5
• Development of resistance to oral antiviral agents when used episodically in immunocompetent patients is rare (<0.5%) 2, 3, 5

Preventive Counseling

• Identify and avoid personal triggers: ultraviolet light exposure, fever, psychological stress, and menstruation 2, 3, 5
• Use sunscreen or zinc oxide to decrease probability of recurrent outbreaks 3
• Educate about hand hygiene to reduce viral transmission 6

Critical Pitfalls to Avoid

• Starting treatment after lesions have fully developed - efficacy decreases significantly when treatment is not initiated during prodrome or within 24 hours 2, 3, 5
• Relying solely on topical treatments when oral therapy is indicated and far more effective 2, 3, 5
• Using topical antivirals for suppressive therapy - this is completely ineffective 2, 3, 5
• Failing to consider suppressive therapy in children with ≥6 recurrences per year who could benefit from 75% reduction in episodes 2, 3, 5
• Confusing cold sores with other conditions - in children with neurological symptoms (altered consciousness, seizures, focal deficits), consider HSV encephalitis and initiate IV acyclovir immediately while pursuing diagnostic workup 7

Special Considerations

• For immunocompromised children, higher doses or longer treatment durations may be required 2
• Episodes are typically longer and more severe in immunocompromised patients, potentially involving the oral cavity or extending across the face 2
• Resistance rates to acyclovir are higher in immunocompromised patients (7% vs <0.5% in immunocompetent) 2