The cause of rosacea is not fully understood, but latest research suggests that the defect lies in the blood vessels in the skin of the face, which dilate too easily. Rosacea is more common in women than in men, and in those with a fair skin who flush easily.
Many things seem to make rosacea worse, but probably do not cause it in the first place. These include alcohol, too much exercise, both high and low temperatures, hot spicy foods, stress, and sunlight. Things that stir up one’s rosacea may well have no effect at all on the rosacea of someone else. The idea that rosacea is due to germs in the skin, or in the bowel, has not been proved.
Rosacea is not contagious. Rosacea does seem to run in some families but it is still not clear whether heredity plays a big part in this. Most common Rosacea trigger is Sun exposure. Making a broad spectrum sun screen of 30+ as part of your day to day skin care.