The Sun
Sunlight, more specifically, UV light is a known trigger of cold sores, but it doesn’t mean you should spend your summer hiding inside. Using a broad-spectrum sunscreen and lip balm, which provide sun protection can reduce and even prevent an outbreak. It’s recommended that you use a minimum SPF of 15.
It’s also important to remember to reapply frequently, as sunscreen’s effectiveness can be affected by wind, water, humidity, and altitude. What is more, you can sweat or lick your lip balm off without realizing it.
It’s important to wear sunscreen even on cloudy days, as UV rays can penetrate clouds and even thick fog.
