THE CLINICAL AND PATHOLOGICAL EFFECTS OF PROLONGED SOLAR EXPOSURE: I.‐THE ASSOCIATION WITH AGEING OF THE SKIN

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Abstract
Summary: A histological study of the skin of 50 patients is presented comparing the findings in exposed and unexposed regions and relating the changes seen to age and exposure.The unexposed skin does not alter significantly in structure with age. The different appearance of the aged skin in unexposed areas is due to alterations in physical properties for which there is no matching alteration in morphology.The exposed skin shows changes predominantly in the dermis. These are described as “basophilic degeneration of collagen or “elastotic degeneration of collagen, which are synonymous with “senile elastosis.It is suggested that “collagen degeneration is a more suitable term than elastosis.It is found that the changes occur only on exposed regions and should be termed “solar degeneration as they are not primarily due to age.The factors influencing the development of solar collagen degeneration are as follows:(a) The fair skinned lightly pigmented patient is most susceptible and despite prolonged exposure does not develop satisfactory protective pigmentation. Heavily pigmented skin is protected as evidenced by the lack of collagen degeneration in dark skinned people and particularly in the aboriginal.(b) The degree of collagen degeneration corresponds well with the degree of exposure.(c) As age increases the degree of collagen degeneration is greater. However, this is proportional to the amount of exposure rather than to the age.(d) Sex: Men are affected more than women but this is related to increased exposure rather than to a variable susceptibility.The changes seen microscopically correlate well with the macroscopic appearance of the skin and explain the difference between the exposed and covered areas.These changes are responsible for the prematurely aged appearance of people exposed to the elements who are not heavily pigmented.A warning note is sounded in relationship to the ill effects of over exposure to the sun in fair skinned people. The price that sunlovers must pay is at least a prematurely aged appearance. The possible relationship between solar collagen degeneration and skin cancer will be discussed subsequently. Prevention of solar collagen degeneration by limitation of exposure in susceptible individuals is advised.