Repeated solar injuries over many years ultimately can result in the development of a skin syndrome, dermatoheliosis. Dermatoheliosis (DHe) results from excessive and/or prolonged exposure of the skin to ultraviolet radiation (UVR) in persons with SPT I to III and in persons with SPT IV who have heavy exposure to sunlight, such as lifeguards and outdoor workers. The syndrome results from the cumulative effects of sun exposure after the first exposures in early life. DHe describes a polymorphic response of various components of the skin (especially cells in the epidermis, the vascular system, and the dermal connective tissue) to prolonged and/or excessive sun exposure. As stated previously, the severity of DHe depends principally on the duration and intensity of sun exposure and on the indigenous (constitutive) skin color and the capacity to tan (facultative melanin pigmentation).
While UVB is the most obvious damaging UVR, UVA in high doses can produce connective tissue changes in mice. In addition, visible (400 to 700 nm) and infrared (1000 to 1,000,000 nm) radiations have been implicated. The action spectrum for DHe is not known for certain; there is some experimental evidence in mice that infrared radiation is implicated, in addition to UVB and UVA.
The most obvious symptoms of photo aging are:
* dark age spots on the face and decollete
* uneven complexion
* leathery skin
* fine lines
* a gradual thickening of the skin
* deep wrinkles around the eyes
Joke and Humors
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