Cold sores are caused by the herpes simplex virus (HSV-1). Once you’ve had a cold sore, it’s likely you will have more over the course of your life. Stress, illness, hormones, and more can trigger outbreaks.

Cold sores are painful, open blisters that develop in or around your mouth, usually on your lips. After you get an HSV infection, the virus travels to nearby nerve cells, where it can lie dormant for long periods of time.

When triggered, the virus can replicate again, causing another cold sore.

It can be hard to predict what triggers a cold sore, and they might seem to appear at the worst times.

But research has identified some common triggers.

We’ve partnered with Burt’s Bees, known for its lip balms and other lip care products, to explore the triggers of cold sores and help you prevent and prepare for future flare-ups.