Abstract
Abstract
Solar ultraviolet radiation (UVR) is ubiquitous and has many molecular, cellular and clinical effects on healthy human skin. These effects can affect the skin directly and/or have systemic consequences and are heavily dependent on constitutive skin pigmentation. This chapter provides an overview of solar UVR and its effects on skin, as well as their mitigation, and provides a background for the understanding of phototherapy and the photodermatoses that are discussed in other chapters. Dermatologists have largely focused on the adverse effects of sunlight but there is increasing interest in clinical benefits other than vitamin D synthesis.