Skin cancer may also occur as a late sequela to radiodermatitis, trauma, burns, scars, or chronic ulcers. Occasionally, it appears as a late manifestation of certain chronic infectious granulomatous diseases. Immunosuppression may also be a predisposing factor. The acute phototoxic effect of excessive sun exposure, a sunburn, is obvious. Cutaneous aging results from a combination of genetically based endogenous factors and the effects of chronic sun exposure.
Senescent skin is typically thin and displays loss of elasticity and deepened expression lines.
Histologic findings include epidermal dysplasia with cytologic atypia and a disorientation of keratinocytes. Dermal damage is manifested as solar elastosis with fragmentation of elastic fibers and a decrease in skin collagen. Environmental factors that may contribute to photoaging include wind, heat, chemical toxins, and cigarette smoke. Hyperpigmentation and solar freckling became less prominent but did not disappear. There was no apparent change in telangiectasias.