Triggers of Cold Sores

No one is certain exactly how HSV-1 is triggered. Certain factors may potentially trigger cold sore outbreaks in infected individuals. Ultraviolet radiation from sunshine or tanning booths are common triggers. Stress, fatigue, fever, illness, cold weather, windburn, drying of the lips, and trauma such as cuts from shaving or dental work may also lead to a cold sore outbreak. Hormonal disturbances from menstruation or pregnancy may also be triggers in women.