Sunscreens are very important for the prevention of ultraviolet light (UVL)–related disorders such as skin cancer and photoaging (eg, wrinkles).12 Several factors are important in the selection of a sunscreen including the sun protection factor (SPF) rating, the active ingredient, and the vehicle (Table 6-6). The SPF is a measurement of a sunscreen's ability to protect the skin against UVL in a laboratory setting. For example, if someone normally sunburns after 20 minutes of sunlight exposure, theoretically a SPF 15 sunscreen would protect him or her from burning for 15 × 20 minutes or 5 hours. However, there are several factors that in real life use of sunscreen reduce the level of protection. For maximum effectiveness sunscreens should be used as follows:
Broad-spectrum sunscreens with SPF of 15 to 30 or higher should be used
Applied 15 to 30 minutes before exposure
Applied at the amount of 30 g (1 oz) per application if an entire adult body is to be covered
Reapplied every 2 hours or after swimming or excessive sweating
Kept at room temperature, not stored in car
Table 6-6.Sunscreen ingredients. ||Download (.pdf) Table 6-6. Sunscreen ingredients.
|Ingredients ||Chemical Agents ||Brand Name Examples ||Notes |
|Inorganic ingredients ||Zinc oxide, titanium dioxide ||Neutrogena Sensitive Skin Lotion, Vanicream SPF 30 or 60 Lotion ||Best for individuals with allergies to sunscreens or who need visible light protection and children. May appear white on the skin |
|Organic ingredients ||Benzophenones, cinnamates, padimates, salicylates ||Aveeno, Banana Boat, Cetaphil, Coppertone, generic, Hawaiian Tropic creams, gel, lotions and sprays ||Available in wide range of vehicles. Some are water resistant, may stain clothing |
FDA sunscreen regulations on labeling of sunscreens were changed in 2012. Some of these rules include criterion for the term "broad spectrum" and water-resistant claims will be specific (ie, sunscreen remains effective for 40 or 80 minutes after swimming). There will also be a limit on the SPF that can be claimed.
Clothing commonly worn in the summer such as cotton, rayon, and linen may not offer sufficient protection from UVL for some fair-skinned or photosensitive individuals.13 Polyester fabrics offer higher level of protection, but for prolonged sun exposure, sun protective clothing is a better option. The following are examples of companies that offer a wide range of sun protective clothing, swimwear, and hats for children and adults:
Some people are unwilling to limit UVL exposure because they want a tan. Sunless tanning products are an option for some of those individuals who want to have the appearance of a tan without exposure to the sunlight or tanning beds. These products usually contain dihydroxyacetone (DHA) that interacts with the amino acids in the stratum corneum to produce a temporary tanned appearance to the skin. DHA in a lower concentration in a daily moisturizer (eg, Jergens Natural Glow and Neutrogena Build-A-Tan) is associated with less streaking. Sunless tanning products are not sunscreens and do not protect against sunburns.
Additional information about sun protection can be found at the Web site of the Skin Cancer Foundation (www.skincancer.org) and the American Academy of Dermatology (www.AAD.org).