Pathophysiology of Premature Skin Aging Induced by Ultraviolet Light

Ultraviolet irradiation from the sun has deleterious effects in human skin, including sunburn, immune suppression, 1 cancer, and premature aging (photoaging). Sunburn and immune suppression occur acutely in response to excessive exposure to the sun, whereas skin cancer and photoaging result from accumulated damage caused by repeated exposures. Skin cancer, the most prevalent form of cancer in humans, 2 typically occurs in skin that is photoaged. 3 Photoaged skin is characterized by wrinkles, laxity, uneven pigmentation, brown spots, and a leathery appearance. 4 In contrast, chronologically aged skin that has been protected from the sun is thin and has reduced elasticity but is otherwise . . .