Cold sores: symptoms, treatment, how long they last and how to stop them spreading

The NHS says cold sores usually clear up on their own within 10 days, and there are things you can do to help ease the pain. A pharmacist can recommend creams to ease pain and irritation, antiviral creams to speed up healing time and cold sore patches to protect the skin while it heals.

The NHS says that if you regularly get cold sores, use antiviral creams as soon as you recognise the early tingling feeling, because they do not always work after blisters appear. Patient's professional guidance says the benefits of topical antivirals are small and cold sores usually resolve within 7 to 10 days even without treatment, that treatment needs to start at the onset of symptoms before blisters appear and be applied frequently for a minimum of 4 to 5 days.

The NHS says you can buy electronic devices from pharmacies that treat cold sores with light or lasers, which you may find helpful, but there is not much evidence to confirm they work.

A GP may prescribe antiviral tablets if your cold sores are very large, painful or keep coming back, the NHS says. Patient says that for people with a normal immune system oral antivirals are not routinely indicated but may be used in severe episodes, ideally from the time of the tingling stage.

The NHS says a cold sore usually starts with a tingling, itching or burning feeling. Over the next 48 hours one or more painful blisters will appear on your face. Cold sore blisters are usually small and filled with fluid. Cold sores should start to heal within 10 days but are contagious and may be irritating or painful while they heal.

The NHS says cold sores are common and usually clear up on their own within 10 days, and should start to heal within 10 days. Patient says they usually resolve within 7 to 10 days even without treatment.

The NHS says to see a GP if a cold sore has not started to heal within 10 days.

Yes. The NHS says cold sores are contagious from the moment you first feel tingling or other signs of a cold sore coming on to when the cold sore has completely healed, and that they can easily spread to other people and other parts of your body.

To help stop cold sores spreading, the NHS suggests washing your hands with soap and water whenever you touch your cold sore, not kissing anyone while you have a cold sore, and not having oral sex until your cold sore completely heals, as you could give your partner genital herpes. Patient adds that you should dab topical medications on rather than rub them in, not share lipstick or lip gloss, and that there is a risk of transmission to the eye if contact lenses become contaminated.

Patient also says children with cold sores do not need to be excluded from nurseries and schools.

The NHS says cold sores are caused by a virus called herpes simplex. Most people are exposed to the virus when they are children after close skin to skin contact, such as kissing, with someone who has a cold sore. Once you have the virus, it stays in your skin for the rest of your life, and sometimes it causes a cold sore.

The NHS says certain things may trigger a cold sore, such as illness, sunshine or being on your period. It advises avoiding anything that triggers your cold sores, such as sunbeds, and using sunblock lip balm (SPF 15 or above) if you are outside in the sun.

The NHS lists things that help ease cold sores while they heal and avoid triggering them.

• Take paracetamol or ibuprofen to ease pain and swelling; liquid paracetamol is available for children; do not give aspirin to children under 16.

• Drink plenty of fluids to avoid dehydration.

• Do not touch your cold sore apart from applying antiviral cream, and wash your hands before and after if you do.

• Do not rub cream into the cold sore; dab it on instead.

• Do not eat acidic or salty food if it makes your cold sore feel worse.

• Avoid anything that triggers your cold sores, such as sunbeds, and use a sunblock lip balm (SPF 15 or above) in the sun.

The NHS says newborn babies, pregnant women and people with a weakened immune system who have cold sores may be referred to hospital for advice or treatment. Patient says to seek specialist advice if the person is pregnant, particularly in the third trimester, because the risk of transmission to the baby from kissing is greatest when infection develops in the third trimester, as maternal antibodies have not had time to develop.

The NHS neonatal herpes page explains how a newborn catches herpes after birth: the herpes simplex virus can be passed to a baby through a cold sore if a person has a cold sore and kisses the baby, and the baby is thought to be most at risk in the first 6 weeks after birth. Tell your midwife or doctor if you have a cold sore, and check with a pharmacist, midwife or doctor before using a treatment in pregnancy.

The NHS says kissing a baby if you have a cold sore can lead to neonatal herpes, which is very dangerous to newborn babies. It advises that everyone should wash their hands before handling a baby, that anyone who is not a close family member or carer should be discouraged from kissing the baby, that the safest place to kiss a baby is on the top of the head and that people with a current cold sore or a recent history of cold sores should not kiss the baby.

The NHS says to call a GP or NHS 111 straight away if your baby is irritable and will not settle, is not feeding as well as usual, has a high temperature of 38C or more, or has a rash or sores on their skin, eyes and inside their mouth. Call 999 immediately if your baby is lacking in energy, floppy, not responding to you in their normal way, difficult to wake, breathing rapidly or has a seizure.

The NHS says to see a GP if a cold sore has not started to heal within 10 days, you are worried about a cold sore or think it is something else, the cold sore is very large or painful, you or your child also have swollen, painful gums and sores in the mouth (gingivostomatitis), or you have a weakened immune system, for example because of chemotherapy or diabetes.

Patient says to seek medical advice if the lesion spreads, a new lesion develops after the initial outbreak, there is persistent fever or inability to eat, or there is no improvement after 7 to 10 days.

A pharmacist is the usual first stop for cold sore treatment on the NHS. Antiviral creams and patches are available over the counter. A GP can prescribe antiviral tablets for very large, painful or recurring cold sores and can arrange hospital advice for babies, pregnancy and weakened immunity.

Private consultations are available, including online ones that can supply antiviral treatment. The same advice applies: antiviral cream works best when used at the first sign, and any cold sore near a baby needs care.