Recent scientific publications continue to address the challenges of protecting human skin against the damage caused by insolation (i.e., exposure to the sun’s rays). Unfortunately, in the United States, much of this worldwide technical effort cannot be used for cosmetic products because regulatory approach has not been granted. Thus, novel sunscreen agents or their combinations may not be offered for sale in the North American market.
David Steinberg, Steinberg & Associates, who publishes a column in this publication, has claimed that the U.S. Food and Drug Administration (FDA) “drags its feet.” This issue was also aired in the April Chemical & Engineering News, with the observation that only 16 sunscreens have been approved in the United States, while 28 have been approved in the European Union (EU).
The skin’s initial response to sun exposure or sun damage is erythema (reddening of the skin) and pigment formation (tanning). Continued exposure to ultraviolet (UV) light causes wrinkling (photoaging). The recognition of UV rays in sunlight as the damage-provoking entity is a major scientifi c milestone, and UV is a causative factor in the formation of skin cancers. The mechanisms for these events have been identifi ed in recent years and include formation of reactive oxygen species (ROS), a variety of free radicals, lipid peroxides and, especially, superoxide anion radicals.
Classically, melanin formation provides protection against sunburn. However, Caron-Schreinemachers and associates in Holland1 note that pigment-lacking skin of vitiligo patients shows evidence of intrinsic skin protection. This is a highly signifi cant observation and provides evidence that skin—even in the absence of melanin— shows some modest protection against erythema with increasing (Fitzpatrick) skin photo type. They suggest that this level of protection may be provided by the antioxidant status of the skin, and their conclusions validate this as a second natural photoprotective mechanism in human skin, which provides support for the frequently noted importance of antioxidant vitamins in the skin.