Cold sores are very common. They are painful blisters caused by the herpes simplex virus which appear on your mouth and lips. Although it’s thought that around seven in every ten people carry the virus which causes cold sores, many don't know they have it because it doesn’t always cause symptoms.
Cold sores are caused by a common virus called the herpes simplex virus type 1. The herpes simplex virus is often passed on when you’re very young through physical contact like a kiss from a family member or friend who has it, but it lies dormant until it’s triggered at a later date. In some people it will just stay dormant and never cause any problems, but others develop cold sores. Most people who have the herpes simplex virus will have come into contact with it between the ages of three and five - but the symptoms often don’t appear until after puberty.
Once you have the virus in your body there’s no cure for it, but there are some things you can do to avoid getting it in the first place and limit flare ups of cold sores if you do have it.
To prevent getting the virus, the number one thing you can do is avoid coming into close physical contact with anyone who has an active flare up. Don’t share cutlery, cups or anything else that someone with cold sores might have used.