Cold sores

Cold sores are common and usually clear up on their own within 10 days. They’re contagious until they go away.

Check if it’s a cold sore

A cold sore usually starts with a tingling, itching or burning feeling.

Over the next 48 hours:

Cold sores should start to heal within 10 days - but may spread and be irritating or painful while they heal.

Some people find that certain things trigger a cold sore, such as another illness, sunshine or periods.

When it's not a cold sore
Symptoms Possible cause
Painful, red spot on the face, filled with pus spot or boil
Blister on the lip or inside the mouth mouth ulcer
Red sores or blisters on face that become crusty, golden-brown patches impetigo

A pharmacist can help with cold sores

A pharmacist can recommend:

  • creams to ease pain and irritation
  • antiviral creams to speed up healing time
  • cold sore patches to protect the skin while it heals

You can buy electronic devices from pharmacies that treat cold sores with light or lasers. Some people find these helpful - but there haven't been many studies to find out if they work.

If you regularly get cold sores, use antiviral creams as soon as you recognise the early tingling feeling. They don't always work after blisters appear.

Things you can do yourself

Cold sores take time to heal and they're very contagious - especially when the blisters burst.

Don’t kiss babies if you have a cold sore. It can lead to neonatal herpes, which is very dangerous to newborn babies.

Do

  • eat cool, soft foods
  • use an antiseptic mouthwash if it hurts to brush your teeth
  • wash your hands with soap and water before and after applying cream
  • avoid anything that triggers your cold sores
  • use sun block lip balm (SPF 15 or above) if sunshine is the trigger
  • take paracetamol or ibuprofen to ease pain and swelling (liquid paracetamol is available for children) - don’t give aspirin to children under 16
  • drink plenty of fluids to avoid dehydration
  • wash your hands with soap and water before and after applying cream

Don't

  • eat acidic or salty food
  • touch your cold sore (apart from applying cream)
  • rub cream into the cold sore - dab it on instead
  • kiss anyone while you have a cold sore
  • share anything that comes into contact with a cold sore - such as cold sore creams, cutlery or lipstick
  • have oral sex until your cold sore completely heals - the cold sore virus also causes genital herpes

See a GP if:

  • the cold sore hasn’t started to heal within 10 days
  • you're worried about a cold sore or think it's 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)
  • you’re pregnant - there's an increased risk of neonatal herpes
  • you have a weakened immune system - for example, because of chemotherapy or diabetes

Treatment from a GP

The GP may prescribe antiviral tablets if your cold sores are very large, painful or keep coming back.

Newborn babies, pregnant women and people with a weakened immune system may be referred to hospital for advice or treatment.

Why cold sores come back

Cold sores are caused by a virus called herpes simplex.

Once you have the virus, it stays in your skin for the rest of your life. Sometimes, it causes a cold sore.

Most people are exposed to the virus when they are young - after close contact with someone who has a cold sore.

It doesn't usually cause any symptoms until you're older. You won't know if it's in your skin unless you get a cold sore.

Call 111

If you can’t speak to your GP or don’t know what to do next.

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