Cold Sores (Herpes Simplex) in Ireland — Patient Guide

What are cold sores?

Cold sores (medical name herpes labialis) are a recurrent viral infection of the lips and surrounding skin caused by herpes simplex virus type 1 (HSV-1). Most adults in Ireland — around 60-80% — carry HSV-1, though many never have visible outbreaks. The virus stays dormant in nerve cells and reactivates intermittently, producing the characteristic cluster of blisters.

Typical course

Per NICE CKS, a typical outbreak progresses:

• Tingling/burning (prodrome): 12-24 hours before any visible lesion — the best time to start treatment
• Blisters: small fluid-filled vesicles cluster on or around the lip
• Weeping/ulcer phase: blisters burst
• Crusting: yellow-brown scab forms
• Healing: 7-10 days total without scarring in most cases

First-ever outbreaks may be more severe — with fever, swollen glands, and widespread mouth ulcers (primary herpetic gingivostomatitis). Subsequent recurrences are usually milder.

Common triggers

• Sun exposure (UV light) — a major trigger; sun-protection on lips helps prevent recurrence
• Other illness, particularly with fever
• Stress, fatigue, lack of sleep
• Menstruation
• Local trauma — dental work, lip injury, even kissing if skin is split
• Immunosuppression — illness or medications

Treatment options

Per NICE:

• Topical aciclovir cream — applied at the first sign of tingling, 5 times a day for 5-10 days. Most effective when started very early; modest benefit if started after blisters appear. Over-the-counter in Irish pharmacies
• Oral antivirals (aciclovir, valaciclovir, famciclovir) — for severe outbreaks, frequent recurrence (6+ per year), or immunocompromised patients. Prescription-only
• Suppressive antiviral therapy — continuous low-dose oral antiviral for very frequent recurrences. Usually after specialist review
• Symptomatic relief — paracetamol or ibuprofen for pain; barrier creams (petroleum jelly) protect crusts; soft cool foods
• Avoid topical corticosteroids on cold sores — they worsen viral spread

Prevention and reducing spread

• Daily SPF 30+ lip balm — UV is a major trigger
• Hand hygiene around active sores
• Don't share lip products, towels, cutlery, drinks during outbreaks
• Avoid touching eyes after touching cold sores
• Avoid kissing or oral sex during active outbreaks
• Don't pick at scabs — let them heal naturally

When to seek urgent care

Most cold sores are managed at home or with Online Doctor support. Seek urgent care for any of:

• Cold sore near the eye or any eye symptoms (redness, pain, vision change) — risk of herpes keratitis, which can threaten sight
• Widespread painful blisters over the face or body
• Cold sore in someone with eczema (risk of eczema herpeticum)
• Severe outbreak with high fever and feeling generally unwell
• Immunocompromised patients (cancer treatment, transplant, HIV, certain medications)
• Newborn baby contact concerns

Online Doctor consultation

An Online Doctor consultation is appropriate for: severe or frequent recurrences, prescription of oral antiviral treatment, suppressive therapy discussion, or treatment in pregnancy. For complications or atypical presentations, in-person assessment is preferred.