Cold sores

Cold sores

What causes cold sores?

Cold sores are caused by the herpes simplex virus, and usually the herpes simplex virus type 1 (HSV-1). About 90% of people will be infected by HSV-1 at some point in their lives. The first infection may not even be noticed or it may cause a flu-like illness and painful ulcers in the mouth.

Following the first attack, the virus will lie dormant in nerve cells, but, in some people, it is triggered and reactivates. The reasons for this reactivation are not fully understood, but may include:

How are cold sores spread to others?

They can be spread by contact such as kissing but also by sharing toothbrushes, towels, cutlery, etc.

What happens during an outbreak?

Most cold sores heal in about one week

How are cold sores treated?

In most cases, cold sores are an irritating nuisance which clear up within a few days. However, over-the-counter treatments are available for more troublesome outbreaks and are most effective if applied as soon as you feel tingling or itching develop. You should only consult your doctor if the cold sore is accompanied by fever, red or sore eyes, or if the area is very inflamed and you notice a yellow-coloured discharge.

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