Cold Sores: Treatment & Prescription Antivirals via UK Online Doctor
Educational information — not medical advice.
This article was prepared by the OnlineDoctor24 editorial team and reviewed for factual accuracy against UK clinical guidance (NHS and NICE). It is not written by a doctor and does not replace personal medical advice. For symptoms specific to you, book an online doctor consultation.
Key points
- Cold sores are caused by herpes simplex virus type 1.
- Treat at the first tingling sensation for best results.
- Aciclovir cream is over the counter; oral aciclovir or valaciclovir is prescription-only.
- Frequent recurrences (>6/year) may benefit from daily suppressive treatment.
- An online GP can prescribe oral antivirals.
Stages of a cold sore
- Tingling/itching (12–24 h)
- Blisters appear
- Ulceration and weeping
- Crusting
- Healing (10–14 days total)
Treatment
- Aciclovir 5% cream — apply at first tingle, 5 times a day for 5 days.
- Oral aciclovir 200 mg 5×/day or valaciclovir 2 g twice on day 1 — most effective if started early.
- Daily suppressive aciclovir 400 mg twice daily for frequent recurrences.
- Pain relief with paracetamol/ibuprofen.
Prevention
- Use SPF lip balm — sunlight is a common trigger.
- Avoid sharing towels, lip balm or kissing during outbreaks.
- Manage stress and sleep.
Red flags — when to seek urgent help
Call 999 or go to A&E if you experience any of the following:
- Cold sore near or in the eye (urgent ophthalmology)
- Widespread blistering on eczematous skin (eczema herpeticum)
- Severe outbreaks in immunosuppressed people
Frequently asked questions
Common questions UK patients ask about herpes simplex (cold sores).
How an online doctor can help
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This article is for general information only and does not replace personal medical advice from a qualified doctor. Content is reviewed against UK NHS and NICE guidance by the OnlineDoctor24 editorial team and is not authored by a medical doctor. If your symptoms worsen or you are unsure, please book a consultation with a GMC-registered GP.
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