ABSTRACT
INTRODUCTION Ultraviolet radiation (UVR) from the sun is divided into UVA (UVA1 340-400 nm and UVA2 320-340 nm), UVB (290-320 nm), and UVC (270-290 nm). UVC is filtered by ozone in the stratosphere, whereas UVA and UVB reach the earth’s surface. UVA can penetrate deeper through the skin than UVB, is not filtered by glass, and it is estimated that approximately 50% of exposure to UVA occurs in the shade (1). Acute exposure to UVB causes effects such as erythema, edema, tanning, thickening of the epidermis and dermis, and vitamin D synthesis. Chronic exposure to UVB can result in photoaging, immunosupression, and photocarcinogenesis (2,3). Exposure to UVA is more efficient in inducing tanning and causes less erythema, but it is also involved in photoaging and acute and chronic photodermatoses (4). Both UVA and UVB are associated with immunosupression and carcinogenesis (5); therefore, there is a need for protection.
