Patient information · Dermatology
Cold sores
treat at the tingle, not at the blister
Cold sores are caused by the herpes simplex virus, which most people acquire in childhood and which then stays dormant in a nerve for life. Around one in five people get recurrent outbreaks. Treatment works, but only if it starts within the first day — ideally at the tingling stage before anything is visible.
Seek urgent assessment if there is
- a cold sore near or in the eye, or eye pain, redness or blurred vision
- a cold sore in someone with eczema that is spreading — this can become eczema herpeticum
- an outbreak in a newborn baby, or in someone immunosuppressed
- widespread blisters, high fever or feeling seriously unwell
- an outbreak that is not healing after two weeks
Herpes affecting the eye can threaten sight and needs same-day ophthalmology. Eczema herpeticum spreads rapidly and requires urgent antiviral treatment. Never kiss a newborn if you have an active cold sore — neonatal herpes is rare and can be life-threatening. In an emergency call 999, or go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
The stages
- Tingle — itching, burning or tingling for a few hours before anything appears. This is when treatment works.
- Blister — small fluid-filled blisters, usually at the lip border, over one to two days
- Weeping — blisters burst; the most infectious stage
- Crusting — a scab forms, often cracking and bleeding
- Healing — typically complete in 7 to 10 days without scarring
Treatment
- Antiviral cream applied at the first tingle, five times a day for five days. Started at the blister stage it makes little difference — which is why most people conclude it does not work.
- Antiviral tablets are more effective than cream, particularly for severe or frequent outbreaks, and can be prescribed as a standby supply to keep at home and start immediately.
- Cold sore patches protect the area, reduce spread and improve appearance while healing.
- Paracetamol or ibuprofen for discomfort; petroleum jelly to stop the scab cracking.
- For very frequent outbreaks — six or more a year — suppressive daily antiviral treatment substantially reduces frequency.
Triggers
- Sunlight — the most common trigger. An SPF lip balm used routinely prevents a meaningful proportion of outbreaks.
- another infection, particularly a cold or fever
- stress, exhaustion, and poor sleep
- hormonal changes, particularly around periods
- trauma to the lip — dental work, cosmetic procedures, chapping
- sunbeds, cold wind, and immunosuppression
Avoiding spread
Do
- Wash hands after touching the sore
- Use your own towel, flannel, cup and cutlery
- Replace your toothbrush after an outbreak
- Use SPF lip balm routinely if sun is a trigger
- Tell your dentist if you have an active sore
Do not
- Do not kiss anyone, especially babies and children
- Do not have oral sex during an outbreak — it transmits to the genitals
- Do not share lip balm, razors or make-up
- Do not pick or squeeze the blisters
- Do not wear contact lenses without scrupulous handwashing
Before cosmetic treatment
Lip fillers, laser resurfacing, microneedling and dermabrasion around the mouth commonly trigger an outbreak, which can then affect the result and occasionally cause scarring. If you get recurrent cold sores, tell your practitioner — preventive antiviral tablets started before the procedure and continued for a few days afterwards substantially reduce the risk. This is standard practice and is worth asking for.
Why come to us. Cold sores are easy to treat and very hard to treat late. We can prescribe antiviral tablets as a standby supply so the next outbreak is treated within the hour rather than after a pharmacy conversation two days in, and can arrange suppressive treatment if outbreaks are frequent. We also provide preventive cover before aesthetic procedures around the mouth. Open seven days a week, with online booking and no referral needed.
Standby antivirals, ready before the next outbreak
Book online, seven days a week, no referral needed.
Tower Bridge Hospital London
97–99 Whitechapel Road, London E1 1DT
WhatsApp 07903 284 189
info@mhwclinic.co.uk
Open Mon–Sat, 9am–7pm (closed Sundays until September)
In an emergency
Call 999, or go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
When we are closed and it is not an emergency
Call NHS 111 or visit 111.nhs.uk.