A cold sore usually starts with a tingling, itching or burning feeling, they are common and usually clear up on their own within 10 days. They’re contagious until they go away.

How can I avoid triggers? Suggested lifestyle changes…

Some people find that certain things trigger a cold sore, such as another illness, sunshine or periods. If you regularly get cold sores, it may be a good idea to keep antiviral cream in your medicine cabinet. As soon as you recognise the early tingling feeling of a cold sore use the antiviral creams as they don’t always work after blisters appear.

Why do 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 contact with someone who has a cold sore. It doesn’t usually cause any symptoms until you’re older.

How do I treat?

Cold sores take time to heal and they are 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.


  • 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 sunblock 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.


  • 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.

Examples of products available to buy…

  • Aciclovir Cream (also known as Zovirax)

When should I seek advice?

  • 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.