ABSTRACT
The skin is subjected to relevant alterations during aging. ‘Intrinsic aging’ describes the morphologic and functional alterations due to aging itself. The resulting phenomena are similar to those in other organs, such as a reduction in epidermal growth, synthesis of collagen and elastic fibers, and immune competence. ‘Extrinsic aging’ means the sum of exogenous influences, since the skin as the body cover is exposed to environmental pollutions and toxins more than any other organ during life. The most important burden is the sunlight, which causes a broad spectrum of visible alterations such as skin folds, atropy, and pigment inconsistencies. The most hazardous consequences are the development of malignancies of epidermal and melanocytic cells. More than 1 000 000 new skin cancers are diagnosed per year in the USA, and nearly 10 000 people will die from the disease. The incidence of melanoma tripled between 1980 and 2000 in spite of intense education on the hazards of skin exposuse to UV light. On the other hand, sunlight itself is essential for the production of vitamin D as the main factor for calcium homeostasis and bone density.
