ABSTRACT
This chapter discusses the essential guidelines for protecting human skin against harmful effects of solar radiation. The solar radiation at the earth's surface is subdivided into three spectral bands: ultraviolet radiation, visible radiation and near-infrared radiation of wave-lengths longer than 760 nm. The prevention of sunburn reaction was not obligatory. In 1978, the US Food and Drug Administration classified sunscreens as "drugs" intended to protect the structure and function of the human skin against actinic damage manifested in the form of sunburn, solar elastosis, and possibly skin cancer. The Systemic photoprotective agents recognized as sunscreens can be grouped into two broad categories: topical sunscreens and oral sunscreens. Topical sunscreens can be differentiated into two subcategories: chemical sunscreens and physical sunscreens. Chemical sunscreens are usually colorless preparations that are used topically and contain one or more ultraviolet-absorbing chemicals. Contact sensitization, phototoxicity, and photoallergic reactions may develop from the use of sunscreens.
