Photoprotection

Abstract

Sun exposure is the main cause of photocarcinogenesis, photoageing, and photosensitivity; thus, photoprotection is an important issue. In a skin cancer prevention strategy, behavioural measures--eg, wearing sun protective clothes and a hat and reducing sun exposure to a minimum--should be preferred to sunscreens. Often this solution is deemed to be unacceptable in our global, outdoor society, and sunscreens could become the predominant mode of sun protection for various societal reasons (eg, healthiness of a tan, relaxation in the sun). The application of a liberal quantity of sunscreen has been shown to be by far the most important factor for effectiveness of the sunscreen, followed by the uniformity of application and the specific absorption spectrum of the agent used. The sunscreen market--crowded by numerous products--shows various differences worldwide. Nevertheless, sunscreens should not be abused in an attempt to increase time in the sun to a maximum. Controversies about safety of sunscreens and clinical recommendations are discussed.

Proteção à radiação ultravioleta: recursos disponíveis na atualidade em fotoproteção

“…They can play an important role in some photodermatoses, such as polymorphous light eruption and solar urticaria, as these are sensitive to visible light and UV radiation. 1,4,13,14 …”

“…Therefore, stiffness, color, thickness and weight of the fabric all influence its capacity of photoprotection. 1,13,21 The ultraviolet protection factor (UPF) assesses the degree of protection offered by clothing. It is similar to the sun protection factor (SPF) used for sunscreens; however, it supposedly offers protection against both UVA and UVB radiation, a characteristic that is absent in the SPF, which offers UVB protection only.…”

“…However, the Australian Standard advocates a value of more than 15 UPF. 1,3,13,14,21 New fabrics are currently capable of offering high sun protection. Some new fabrics contain titanium dioxide particles dispersed among their fibers, allowing combined UVA and UVB protection.…”

“…Moreover, the regular use of photoprotectors prevents premature skin aging. 1,3,13,14 Sunscreens are cosmetic preparations that have various presentation forms. They can be found in the form of hydroalcoholic lotions, oils, oily gels, oil in water emulsions (O/A), water in oil emulsions (W/O), sunscreen sticks and sprays, among others.…”

Daily distribution of UV-Index in Belo Horizonte (Brazil) and the shadow rule

“…Many studies have been conducted assessing the outcomes regarding the adoption of protective attitudes like using sun-block cloths, sunscreens, hats, sunglasses and even personal dosimeters (Kullvanijaya & Lim, 2005;Lautenschlager et al, 2007;Carli et al, 2008). In spite of being welcome among people, yet such attitudes have not been able to produce a decrease in the incidence of the harmful biological effects (Dobbinson et al, 2008).…”