Health effects of UV radiation
Skin: sunburn, suntan and skin aging
The best known acute effect of excessive UV exposure is erythema, the familiar skin reddening termed sunburn. In addition, most people will tan from the UV stimulation of melanin production, which occurs within a few days following exposure. A further, less obvious adaptive effect is the thickening of the outermost layers of the skin that attenuates UV penetration to the deeper layers of the skin. Both changes are a sign of damage to the skin.Susceptibility to skin damage depends on skin type; individuals with fairer skin will be more prone to sunburn or erythema, than people with darker skin Similarly, the ability to adapt to UV exposure (able to tan) also depends on skin type.
Chronic exposure to UV radiation also causes a number of degenerative changes in the cells, fibrous tissue and blood vessels of the skin. These include freckles, nevi and lentigines, which are pigmented areas of the skin, and diffuse brown pigmentation. UV radiation accelerates skin aging, and the gradual loss of the skin’s elasticity results in wrinkles and dry, coarse skin.