The cause of rosacea is unknown. Because of this, there is no way to prevent it. It is possible, however, to prevent rosacea flare-ups. In many people, rosacea is triggered by stress, spicy foods, cosmetics, exercise, sun, wind, heat, and cold. Rosacea sufferers can find out what their triggers are by making a list of activities or foods that preceded a flare and avoiding these activities and foods in the future.