The natural process of skin turnover, which
varies from person-to-person based on their exposure to age-accelerating
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
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 mayappear 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.