What causes a cold sore to break out?

Answer 1

Cold sores are caused by the herpes simplex virus (type 1). The original infection began via contact with a person who had an active cold sore or through sharing their utensils, towels or facial razor. The virus comes (active phase) and goes (dormant phase). Things that can make the virus come out of dormancy are stress, fever, menstruation or sun exposure.

Answer 2

1