Aging Skin
The natural process of skin turnover, which varies from
person-to-person based on their exposure to age-accelerating stimuli.
Genetically
programmed chronologic aging causes biochemical changes in collagen and
elastin, the connective tissues that give skin its firmness and elasticity.
The genetic program for each person is different, so the loss of skin
firmness and elasticity occurs at different rates and different times in one
individual as compared with another.
As skin becomes less elastic, it also becomes drier. Underlying
fat padding begins to disappear. With loss of underlying support by fat padding
and connective tissues, the skin begins to sag. It looks less supple, and
wrinkles form. The skin may be itchy with increased dryness. A cut may heal more
slowly.
An important accelerator of skin aging is caused by photoaging;
the effect of chronic and excessive sun exposure on the skin. Photoaging
interacts with chronologic aging and may appear to hasten the process of
chronologic aging. In fact, photoaging may be responsible for the majority of
age-associated changes in the skin’s appearance: mottled pigmentation, surface
roughness, fine wrinkles that disappear when stretched, "age" or "liver" spots (lentigines)
on the hands, and dilated blood vessels. Chronic sun exposure is a major risk
factor for skin cancers—basal cell carcinoma, squamous cell carcinoma and
melanoma.