Photoprotection: The Need
Photosensitivity of the skin results from exposure to sunlight, so absolute avoidance of the sun would eliminate these disorders. Unfortunately, modern contemporary life-styles make this an impractical alternative for most individuals, and this has led to a search for better approaches to photoprotection.
The structural proteins in the epidermis (the outer layer of the skin) confer natural photoprotection, in particular keratins and melanin (pigment responsible for color of the skin). The amount of melanin and its distribution in cells is genetically regulated, and individuals of darker complexion (skin types IV–VI) are at decreased risk for the development of acute sunburn and cutaneous malignancy and other photosensitivity diseases.
Clothing and sunscreens are other common forms of photoprotection. Clothing constructed of tightly woven sun-protective fabrics (irrespective of color), generally affords substantial protection and most people use it. Wide-brimmed hats, long sleeves, hand gloves and trousers all reduce direct exposure.
Sunscreens are now considered to be over-the-counter drugs and category I ingredients and are very good for maintaining patients’ health state, especially skin health state. The U.S. Food and Drug Administration (FDA) considers sunscreens as monographed and safe and effective. Sunscreens are rated for their photoprotective effect by their SPF (sun protection factor). The SPF is a ratio of the time required to produce sunburn erythema with sunscreen application and without sunscreen application. The sunscreens must be rated on a scale ranging from minimal (SPF of more than or equal to 2 and 12) to moderate (SPF more than or equal to 12 and less than or equal to 30) to high (SPF more than or equal to 30, labeled as 30+). No SPF numbered more than 30 can be placed on the label A critical determinant of the sustained photoprotective effect of sunscreens is their water-resistance (other than light absorption).
Some degree of photoprotection can be achieved by limiting the time of exposure during the day. Since in the majority of an individual’s total lifetime sun exposure usually occur by the age of 18, it is important to educate parents and young children about the hazards of sunlight. Simply eliminating exposure at midday will substantially reduce lifetime UV-B exposure and confer good photoprotection.
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