ActinicKeratosesNet Article
When Sun Exposure Unavoidable, Think Photoprotection

Dermatologists routinely tell their patients that sun avoidance - staying out of the sun completely - is the most effective way to protect their skin from the damaging effects of the sun’s ultraviolet (UV) rays. Research shows that premature aging, actinic keratoses (AKs), and skin cancer are sun-induced conditions. While sun avoidance is effective, this advice may not be practical, particularly if a person’s occupation or lifestyle involves outdoor activities.

Since skin should receive as little exposure to UV rays as possible, comprehensive sun-protection practices are recommended when sun avoidance is not possible. Photoprotection is an important part of a comprehensive sun-protection plan, so it is important to know what photoprotection is and how to include it in a sun-protection plan. “Photoprotection” can be defined as “the use of physical and/or chemical agents to prevent the skin-damaging effects from UV radiation in sunlight.” Physical photoprotection is provided by clothing, umbrellas, parasols, awnings, trees, and tents. Sunscreens provide chemical photoprotection.

Before heading outdoors, either to work or for a day of fun, be sure to read the following which explains what you need to know to “think photoprotection.” These principles should be applied year round - not only on hot sunny summer days.

Select Clothing for its Photoprotection Properties
Clothing with a high Sun Protection Factor (SPF) can block nearly 98% of UVA and UVB radiation - a degree of protection especially important for a person who:

• Burns easily and is at high risk for AKs, photoaging, skin cancer and other sun-induced skin conditions

• Receives chronic and intense sun exposure either through an occupation or leisure activity (e.g., farming, construction work, fishing, golfing, and gardening)

What gives clothing a high SPF is the fabric. Tightly woven synthetic fabrics made from nylon or polyester provide maximum photoprotection. Almost as photoprotective, tightly woven cotton blends are more comfortable in hot and humid conditions. Conversely, light-colored fabrics with a loose weave, such as a white cotton t-shirt, do not provide adequate photoprotection - especially when wet.  To get maximum photoprotection select dark colored, tightly woven clothing that covers the skin. Long sleeves and pants are preferable.

If you will be wearing a garment outdoors frequently, you may want to ask your dermatologist about companies that specialize in photoprotective clothing. Your dermatologist also may recommend a laundry additive that can increase the photoprotection provided by clothing.

Since clothing plays such an important role in photoprotection, some garments made specifically for outdoor activities, such as hiking, print the garment’s SPF on a highly visible tag. Fabrics used to make these clothes are woven specifically to provide UV protection and are made to meet SPF specifications.

In addition to wearing photoprotective clothing, dermatologists recommend that anyone who spends time outdoors during the day wear a wide-brimmed hat to shade the face and neck as well as shoes that cover the entire foot.

Seek Shade Whenever Possible
In addition to wearing protective clothing, the American Academy of Dermatology recommends that people seek shade whenever possible. Tents, trees, awnings, and manmade shade structures all provide photoprotection. Erecting a temporary open-air tent or permanent shade structure can provide effective shade and ultraviolet radiation protection for an outdoor area. Whenever possible, seek a shady place.

Sunscreen Provides Photoprotection for Exposed Skin
The American Academy of Dermatology recommends that anyone who will be in the sun for 20 minutes or more wear a broad spectrum (offers protection from both UVA and UVB rays) sunscreen with an SPF of at least 30 on all exposed skin year-round. Sunscreens are designed to aid the body’s natural defense mechanisms in protecting against harmful ultraviolet (UV) radiation from the sun.  They work by absorbing, reflecting, or scattering the sun’s rays on the skin. Since some UV light gets through sunscreens, they should not be the only means of protecting the skin from the sun’s UV rays. 

To be effective, a sunscreen must be:

• Broad-spectrum and have an SPF or 30 or more

• Used on a regular basis, including cloudy days since 80% of the sun’s UV rays pass through the clouds 

• Applied to dry skin 15-30 minutes before going outdoors, and reapplied approximately every two hours to all exposed skin

• Applied to all bare skin - a lip balm that contains sunscreen with an SPF 30 or higher protects the lips

• Reapplied after perspiring or swimming

Sunscreen comes in many forms including creams, gels, lotions, and wax sticks.  The type of sunscreen used is a matter of personal preference; however, it should be broad-spectrum, have an SPF of 30 or more, and be used as indicated above. If uncertain about which sunscreen to use, ask a dermatologist for a recommendation.

Photoprotection Not Just for Warm and Sunny Locales
The risk of developing premature aging, AKs, and skin cancer is not limited to warm and sunny areas, such as Florida and Southern California. One study shows that the risk for AKs can be substantial even in far northern latitudes, especially when a person has AK risk factors - white skin; red or blond hair; a tendency to freckle or burn when exposed to sunlight; and blue, green, or gray eyes. In this study, investigators examined a light-skinned population of 968 men and women over 40 years of age who lived in northwest England, which sits at about the same latitude as Denmark. The overall prevalence of AKs at all ages was 15.4% in men and 5.9% in women. This rose to 34.1% in men and 18.2% in women in those over 70 years of age. In those over 70 with AKs, the presence of AKs was most strongly associated with (1) red hair and freckles, and (2) other indications of photodamage, such as skin mottling and loss of skin elasticity.

Photoprotection: Part of Comprehensive Sun Protection Plan
The American Academy of Dermatology recommends that everyone, including people who have had years of sun exposure, adopt comprehensive sun-protection practices. In addition to wearing protective clothing, seeking shade whenever possible, and wearing a broad-spectrum sunscreen with an SPF of 30 or more, a comprehensive sun protection program includes re-applying sunscreen approximately every two hours or after swimming or strenuous activity, avoiding the sun between 10 a.m. and 4 p.m. when the sun's rays are the strongest, and not using tanning beds and sun lamps.

Photoprotection should be part of this comprehensive sun-protection plan. Remember, before you head outdoors, think photoprotection - wear clothing that is dark colored and has a tight weave, seek shade whenever possible, and apply a broad-spectrum sunscreen that has an SPF of 30 or more to all exposed skin.

References:
AAD Facts About Sunscreens

Pathak MA, et al. Sun-protective agents: formulation, effects, and side effects. In: Freedberg IM, et al (Eds.) Fitzpatrick’s Dermatology in General Medicine, 5^th ed. New York: McGraw-Hill; 1999:2742-63.

Cadet J, et al. Oxidative damage to DNA: formation, measurement, and biological significance. Rev Physiol Biochem Pharmacol. 1997;131:1-87.

Memon AA, et al. Prevalence of solar damage and actinic keratoses in a Merseyside population. Br J Dermatol. 2000 Jun;142(6):1154-9.

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