What are cold sores?

Cold sores, also known as herpes labialis, are caused by the HSV-1 virus and are very common. They can be easy to recognise as they usually appear as red bumps or blisters around the lips and mouth. 

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What causes cold sores?

Cold sores are caused by HSV-1, a form of the herpes simplex virus. In fact, around 90% of adults have been infected with the HSV-1 virus because it’s so contagious. Once infected, the virus never leaves the body.

Most people aren’t exactly sure when they first encountered HSV-1. It’s often contracted in early childhood, and the first infection may not appear as a visible cold sore.

What happens when I get a cold sore?

For the majority of people, HSV-1 remains inactive throughout their lives and they may never know they have the virus. Around 1 in 3 people will experience recurrent infections. The HSV-1 virus ‘wakes up’, infects the cells in or around the lip or mouth and causes a visible and contagious sore. This usually happens after something has triggered the virus, like a run-down immune system or cold, dry weather leading to dry, chapped lips.