Cold sores appear as a cluster of small blisters usually on the lips or around the mouth, especially the corners, and occasionally inside the nose. Approximately 20-40% of people will suffer a recurrent outbreak.
Cold sores are caused by Herpes simplex virus-1 infection (HSV-1).
There are two types of HSV infections:
- HSV type 1 is the commonest cause of cold sores.
- HSV type 2 is more common in the genital area but is also responsible for at least 10% of cold sores in adults
The medical term for cold sores is herpes labialis.