How ultraviolet radiation tans skin

Abstract

The choice to darken one's skin by tanning has gained increased popularity and social acceptance in recent years. The opportunities to tan intentionally have paralleled the dramatic growth of the indoor tanning industry, which asserts that tanning provides health benefits. This increase in intentional tanning has now become a public health issue. To understand why, it is important to understand how ultraviolet radiation (UVR) tans the skin. Tanning is the skin's response to UVR exposures. Interaction between UVR and our skin's pigment system is central to the tanning response. UVR exposure produces DNA damage that directly and indirectly stimulates tanning. The ability of individuals to tan is dependent upon the amount of naturally expressed pigment in their skin. Most germane to the issue of tanning, however, is that UVR-induced DNA damage produces genetic mutations that can lead to skin cancer. This chapter will delineate important biologic aspects of UVR and pigmentation and provide a better understanding of the tanning process and its role as a secondary defense against UVR-induced DNA damage.