In many cases, there is no obvious trigger for a cold sore outbreak. However, factors that are thought to trigger a cold sore include:
- Suffering from an existing infection.
- Suffering from a fever or high temperature.
- Having an existing injury to the affected area.
- Menstruation (periods).
- Exposure to strong sunlight.
- Being tired or fatigued.
- Emotional or psychological stress.
- In some instances, cold sores can be caused by the Herpes Simplex Virus Type 2 (HSV-2). This can occur after having oral sex with a man or woman who suffers from genital herpes, which is a condition typically caused by HSV-2. Genital Herpes presents as painful blisters that develop on and around the genitals.
- If a sufferer is aware of the triggers that, for them, brings on a bout of cold sores, it is recommended they attempt to avoid these triggers. For example, a lip balm containing a sunblock may help prevent the recurrence of infection in someone for whom sunlight is a trigger. A sun-protection-factor of 15 or higher is advised.