The human skin undergoes certain changes when exposed to UV light to protect against damage. The skin's uppermost layer thickens, blocking UV light. The pigment-producing skin cells produce increased amounts of melanin, which tans the skin.
Exposure to sunlight prematurely ages the skin. Exposure to ultraviolet light is responsible for the fine and coarse wrinkles; irregular pigmentation; brown and spots; and leathery skin.
The more sun exposure a person has, the higher the risk of skin cancers. The key to minimizing the damaging effects of the sun is avoiding further sun exposure; damage that is already done is difficult to reverse. Chemical peels, alpha-hydroxy acids, tretinoin creams, and laser skin resurfacing may improve the appearance of thin wrinkles and irregular pigmentation.