Cold sores
Blisters on the lip are familiar to roughly one adult in two. They are usually unpleasant, unflattering and entirely harmless: in a week and a half they…
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Medicines commonly prescribed for Cold sores
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: INJECTABLE PERFUSION, 250 mgActive substance: aciclovirManufacturer: Laboratorio Reig Jofre, S.A.Prescription requiredDosage form: TABLET, 500 mgActive substance: famciclovirManufacturer: Phoenix Labs Unlimited CompanyPrescription requiredDosage form: TABLET, 800 mgActive substance: aciclovirManufacturer: Mabo Farma S.A.Prescription required
Blisters on the lip are familiar to roughly one adult in two. They are usually unpleasant, unflattering and entirely harmless: in a week and a half they clear on their own, and all that is really asked of you is not to spread the virus around. But the same little sore has a few situations in which it stops being a cosmetic matter: the eye, the skin of someone with eczema, and a newborn baby. Those are at the end of this text, and they are the part that matters most.
How it runs, day by day
The script is nearly always the same, and it can be recognised before there is anything to see:
- first comes tingling, itching, burning or a tight feeling on or beside the lip, lasting from a few hours to a day — this is the best moment to act;
- the patch reddens and over about two days small blisters come up, usually in a cluster;
- the blisters burst and leave a weeping raw area, the most infectious stage of all;
- a crust forms on top, pulls tight and cracks, especially when the lip is stretched;
- the crust falls away and the skin beneath repairs itself without scarring.
The whole cycle takes about ten days, sometimes a fortnight. A first-ever encounter with the virus can be harder going: fever, aching, swollen glands under the jaw. In children that first encounter often looks quite different — not one sore on the lip, but ulcers scattered through the whole mouth with swollen, bleeding gums.
Looks similar, is something else
Plenty of things erupt on and around the mouth, and each is handled differently:
- a painful red lump with a head of pus — an ordinary spot or a boil;
- a whitish ulcer on the inside of the lip or cheek, or on the tongue — a mouth ulcer, which has nothing to do with the virus;
- cracks and moisture strictly in the corners of the mouth — angular cheilitis, usually with a fungus, saliva and a shortage of iron or B vitamins behind it;
- blisters and sores in a child that quickly crust over honey-yellow — impetigo, a bacterial infection with a treatment of its own;
- itching, swelling and a fine rash across the whole lip area after a new lipstick or toothpaste — a contact reaction;
- a sore or a hard lump that has sat in one spot for months, never closes and occasionally bleeds — that is certainly not a cold sore, and it needs looking at.
Why it keeps coming back
The culprit is herpes simplex virus, most often type 1. Most people meet it in childhood, through a relative's kiss or a shared spoon or cup. After that first meeting the virus does not leave: it settles in a nerve ganglion at the base of the skull and lives there for the rest of your life without giving a sign.
Every so often something wakes it and it travels back down the nerve to the same bit of lip. Hence the constancy of the location: everyone has their own favourite corner of the mouth. What pushes it out is a cold or any fever, strong sun and sunbeds, wind and frost, short sleep and stress, periods, dental work and a knock to the lip, along with treatments that suppress immunity. Some people get two outbreaks in a lifetime and others several a year, and the frequency usually falls off with age.
Until it has healed, you are infectious
Infectiousness starts with the first tingle and lasts until the skin has closed completely, not until the blisters dry. The virus travels easily both to other people and to your own skin: to a finger, an eyelid, the genitals.
- Wash your hands every time you touch the sore, and better still do not touch it at all except to apply cream.
- No kissing until the crust has gone.
- Leave oral sex until later: the virus from the lip causes genital herpes.
- Do not lend your lipstick, lip balm, towel, cup or cutlery.
- Do not rub your eyes or handle contact lenses with those same hands.
And separately, with no exceptions: do not kiss a newborn, and keep anyone with a lip sore away from one. In a baby in its first weeks, herpes may not stay in the skin but spread through the whole body, and that is life-threatening. If someone in the household has a sore, there are no kisses until it heals, hands are washed thoroughly before picking the baby up, and if the sore is the mother's, a face mask during feeds is sensible.
What helps, and what helps less
Nothing clears the virus from the body, so the aim is more modest: shorten the episode and make it easier.
- Antiviral creams from the pharmacy work only if started in the first hours, at the tingling stage, before blisters appear. Then they shorten the story by roughly a day. Smearing them over a crust that has already formed achieves little; and they are dabbed on, not rubbed in.
- For pain and stinging, ordinary over-the-counter painkillers do the job, as do creams with a local anaesthetic. Children are not given aspirin.
- Patches do not speed up healing, but they cover the sore, stop it catching on things and make it less conspicuous.
- A lip balm with sun protection, winter and summer alike, is the most underrated measure for anyone whose outbreaks are triggered by sunlight.
- Keep drinking if the mouth is sore, and set aside acidic, salty and spicy food for a few days.
- The light and laser gadgets sold for cold sores have no convincing evidence behind them. They rarely do harm either, but the money goes further on an antiviral cream.
Where outbreaks are frequent, a doctor may prescribe antiviral tablets: a short course for each flare or, when the recurrences are truly stubborn, a longer course to prevent them. Steroid ointments are not applied to a cold sore on their own — they quieten the inflammation but make life easier for the virus.
When it stops being cosmetic
Seek help the same day if:
- the eruption appears on the eyelid, by the inner corner of the eye or on the tip of the nose, or if the eye becomes red, watery or painful, dislikes light, or vision goes cloudy — the virus can attack the cornea and leave a scar that damages sight, so this goes to an eye specialist without delay;
- in someone with eczema or atopic dermatitis the blisters spread rapidly across the skin beyond the lip, the skin hurts and a fever starts — that is how a dangerous complication announces itself, and it needs treatment straight away;
- a baby under three months falls ill: listlessness, refusing feeds, fever or blisters on the skin make this an emergency;
- immunity is weakened by chemotherapy, a transplant, HIV or high-dose steroids, and the sore will not heal or keeps spreading.
Not same-day, but not to be shelved either: see a doctor if the sore has not begun to heal in ten days, if it is unusually large and painful, if outbreaks recur more than once a month, if a child's mouth is swollen and bleeding and they refuse to drink, or if you are pregnant and an outbreak appears close to your due date.
Online consultation
A remote appointment handles exactly the questions that press in the first hours, which is when getting to a clinic suits worst. From a photograph and your account, the doctor can say whether this is a cold sore or something else from the list above, advise whether starting an antiviral cream right now is worth it, and, where recurrences are frequent, discuss tablets and the measures that genuinely cut their number. Situations involving a baby at home, and those in pregnancy, are taken separately. Anything to do with the eye, with a spreading rash in someone with eczema, or with an unwell infant does not wait for a screen: that is seen in person, the same day.
This material is for information only and does not replace medical advice.
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