Illness name: cold sores

  • Original languages: English

Description:

Cold sores

Cold sores are common and usually clear up on their own within 10 days. But there are things you can do to help ease the pain.

Check if it's a cold sore

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

Over the next 48 hours:

Small fluid-filled blisters appear.
Credit:

SCIENCE SOURCE/SCIENCE PHOTO LIBRARY https://www.sciencephoto.com/media/257566/view

The blisters can appear anywhere on the face.
Credit:

PAN XUNBIN/SCIENCE PHOTO LIBRARY https://www.sciencephoto.com/media/479137/view

The blisters burst and crust over into a scab.
Credit:

C0473050, DR P. MARAZZI / SCIENCE PHOTO LIBRARY https://www.sciencephoto.com/media/1051811/view/cold-sore-on-lip

Cold sores should start to heal within 10 days, but are contagious and may be irritating or painful while they heal.

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

When it's not a cold sore
Other possible causes of your symptoms
Symptoms Possible cause
Painful red spot on the face filled with pus Spot or boil
Blister on the inside of the lip or mouth Mouth ulcer
Red sores or blisters on the face that become crusty, golden-brown patches Impetigo

How long cold sores are contagious

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.

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 have not been many studies to confirm if they work.

Information:

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

Find a pharmacy

Things you can do yourself

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

Important

Kissing a baby if you have a cold sore can lead to neonatal herpes , which is very dangerous to newborn babies.

Do

  • eat cool, soft foods

  • wash your hands with soap and water before and after applying cream

  • avoid anything that triggers your cold sores

  • use sunblock lip balm (SPF 15 or above) if you're outside in the sun

  • 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

Don’t

  • do not kiss anyone while you have a cold sore

  • do not have oral sex until your cold sore completely heals as you could give your partner genital herpes

  • do not touch your cold sore (apart from applying cream) – if you do wash your hands

  • 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

Non-urgent advice: See a GP if:

  • the cold sore has not 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 have a weakened immune system – for example, because of chemotherapy or diabetes

Treatment from a GP

A 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're young after close skin to skin contact, such as kissing, with someone who has a cold sore.

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

Page last reviewed: 20 July 2020
Next review due: 20 July 2023