What are cold sores?

Cold sores are small blisters on or around the lips, or less often around the nostrils. They usually begin as a crop of small, red bumps that turn into fluid-filled blisters.

What causes cold sores?

Cold sores are usually caused by the herpes simplex virus (HSV) type 1. Exposure to this virus is most common in childhood. The HSV-1 virus enters through small cracks in the skin and travels along the nerves where it can remain quietly inactive for many months or years until, in some people, it is reactivated or “woken up”. The virus then travels down the sensory nerves to the skin, where it multiplies, causing blisters.

Once you have been infected with HSV-1, the virus stays in your body for life, and can reactivate at any time. It is for this reason that cold sores tend to recur.

Over 70% of Australian adults carry the HSV-1 virus¹. However, only approximately 30% of adults in Australia and New Zealand report experiencing cold sores².