Photoaging: pathogenesis, prevention, and treatment

Premature skin aging, or photoaging, results largely from repeated exposure to ultraviolet (UV) radiation from the sun. Photoaging is characterized clinically by wrinkles, mottled pigmentation, rough skin, and loss of skin tone; the major histologic alterations lie in dermal connective tissue. In recent years, a great deal of research has been done to explain the mechanism by which UV induces dermal damage. This research has enabled the identification of rational targets for photoaging prevention strategies. Moreover, studies that have elucidated photoaging pathophysiology have produced significant evidence that topical tretinoin (all-trans retinoic acid), the only agent approved so far for the treatment of photoaging, also works to prevent it. This article summarizes evidence mainly from studies of human volunteers that provide the basis for the current model of photoaging and the effects of tretinoin.