Rosacea is a skin condition in which redness and small, pus-filled bumps develop on the face. It is a genetic inflammatory disorder with no known cause and is more common in people with fair skin and light eyes.

A hypersensitivity to the sun and other factors cause the blood vessels near the surface of the skin to expand and the rush of circulation to the area make the complexion appear red. When the body notices an injury (in this case, the rush of circulation & dilation of blood vessels) it sends more inflammatory cells to the area in an attempt to fix the problem, which exacerbates it.