How to prevent a cold sore outbreak?

If you have never had one before, the most effective way to prevent a cold sore outbreak is by avoiding skin contact with someone who has a cold sore. If you have had a cold sore before, the best way to prevent an outbreak is to avoid triggers such as stress, direct sun exposure, or a weak immune system. Take precautions to keep yourself healthy and start cold sore medications at the first sign of an appearance.