What causes cold sores?

Dr Louisa Draper

"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."

Dr Louisa Draper

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Further Reading

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.

Further Reading