Cold Sores: Causes, Triggers, Treatments, and Prevention

Cold sores (herpes labialis) are caused by herpes simplex virus type 1 (HSV-1). After primary infection, the virus lies dormant in trigeminal ganglia and reactivates periodically.

Common Triggers

• Stress (physical or emotional)
• Fatigue or sleep deprivation
• Illness/fever
• UV exposure (sunlight)
• Hormonal changes (menstruation)
• Dental work or facial trauma
• Immunosuppression

Typical Course

1. Prodrome: tingling, burning, itching (6–24 hrs)
2. Vesicles: clusters of fluid-filled blisters
3. Ulceration: blisters rupture, weep
4. Crusting: yellow-brown scab forms
5. Healing: usually 10–14 days without scarring

Treatment Options

• Oral antivirals (acyclovir, valacyclovir, famciclovir): Shorten duration if started at prodrome.
• Topical antivirals (docosanol, penciclovir): Modest benefit.
• Symptomatic relief: Analgesics, cold compresses, lip balm with SPF.

Prevention

• Avoid direct contact with active lesions
• Use lip sunscreen (SPF 30+)
• Manage stress, prioritize sleep
• Suppressive daily antiviral therapy for frequent recurrences (≥6/year)

Consult a clinician for prescription options if outbreaks are frequent or severe.