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.
A cold sore usually starts with a tingling, itching or burning feeling.
Over the next 48 hours:
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.
Cold sores take time to heal and they're very contagious, especially when the blisters burst.
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
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.