Sunscreen and Sun Protection

It’s important to use a BROAD SPECTRUM sunscreen. These protect us from both ultraviolet B (UVB) and ultraviolet A (UVA) light, both of which are the wavelengths of natural light from the sun that affect our skin. UVB has also been known as the “sun burning” light. UVA can also cause sunburn. UVA can also cause cataracts in our eyes, can damage the defense (immune) function of our skin, cause premature aging and wrinkling of our skin and can interact with some medications and cause sunburns if we’re taking those medications. Some of the more common medications that can make our skin more sun sensitive are diuretics, some antibiotics, antidepressants and medications used to treat diabetes.

For Ultraviolet B sunlight protection, look for a sun protection factor (SPF) of #50 or greater. The represents the factor of time that would be necessary to get sunburned from UVB light when we’re wearing sunscreen compared to when we’re not. For example, when we use an SPF #50 sunscreen, it takes 50 times as much time to get sunburned compared to when we’re not wearing sunscreen.

SPF

The American Academy of Dermatology still recommends using a sunscreen with an SPF of at least thirty. However, a recent study showed that people who used a #100 SPF sunscreen had less sunburn than those using a #50 SPF (Williams, et al; “SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double blind split-face, natural sunlight exposure clinical trial” J Am Acad Dermatol, volume 78, number 5, pages 902-912).

Water resistance

It’s also important to use a sunscreen that is labeled “WATER RESISTANT”. Water resistance can vary in sunscreens between 40-80 minutes. It’s important to reapply sunscreens every 1 ½-2 hours, particularly if you’re perspiring or swimming. Apply sunscreens generously. 3 tablespoons of sunscreen are required to cover our entire sun exposed skin surface.

UPF

UPF stands for ultraviolet protection factor on labels for clothing, hats and fabrics. A shirt with a UPF 50, for example, allows just 1/50th of the UV radiation to reach your skin. It’s also important to remember that clothing leaves some skin exposed, so even though you might be wearing sun protective clothing, it’s important to apply sunscreen to other areas of your skin exposed to the sun.

Glass blocks UVB rays pretty well, but allows UVA rays to pass through. Car windshields most commonly now are treated with products that shield drivers from most UVA. However, side, back and sunroof windows usually don’t contain the same protective treatments. So, adding special tints to those windows might be important for people who are at greater risk for skin cancer. Windows on trains, airplanes and buses do not have ultraviolet light protective coatings, which put pilots and frequent travelers at greater risk for developing skin cancer.

It’s important to avoid direct sun exposure between the hours of 10 am and 4 p.m., when the sun’s rays are most intense. Staying in the shade whenever possible helps, but even if you’re in the shave, UV rays can pass through trees and be reflected off of water, sand, glass and concrete and can still damage our skin.

Sunscreen should not be applied to infants younger than 6 months old, but it’s important that they be protected from UV exposure with clothing, sunglasses, hats and stroller sunshades. Sunscreen can be applied to children six months and older.

How does sunscreen work?

The active ingredients in chemical sunscreens work by absorbing ultraviolet radiation. Some people are allergic to these ingredients. For patients with allergies to chemical sunscreens, physical sunscreens containing titanium dioxide or zinc oxide are alternatives for protection.

Physical sunscreens such as titanium dioxide and zinc oxide work by reflecting and scattering ultraviolet and visible radiation. The large particle size of these ingredients makes them opaque and enables them to block some visible light, but may make them cosmetically unacceptable to patients. As a result, non-opaque, micronized formulations of titanium and zinc oxide have been developed.

The potential of vitamin D deficiency

Since vitamin D is made in our skin, some have raised concerns that use of sunscreens can cause Vitamin D3 deficiency. Vitamin D promotes calcium absorption from our gastrointestinal tract and is necessary for preserving strong bone structure and has many other health benefits. Specific vitamin supplementation amounts vary by age and race. It’s important to maintain adequate amounts of dietary intake of vitamin D, which can be found in fatty fish-- tuna, mackerel, salmon, herring and catfish. Many foods such as dairy products, orange juice, soy milk, cereals, beef liver, cheese, egg are fortified with vitamin D.

New products taken orally or injected subcutaneously to have some potential to reduce the severity of sunburn decrease photosensitivity and prevent photo damage. Larger studies are necessary to learn more about them. Polypodium leucotomos extract, from fern plant, it taken as a pill and has very small protective capabilities against UVB and UVA. However, the SPF value of Polypodium leucotomos extract varies from as low as 3 to as high as 8.

Afamalanotide is an injectable chemical that resembles a hormone in our body that stimulates the production of melanin. Some studies have shown that some patients noticed improvements in duration of pain-free time under direct sun exposure. However, it can also cause headache, nausea, naso-pharyngitis and back pain. It is not FDA approved in the United States and is only approved in Europe for use in some skin diseases that make people very sensitive to the sun.

Zinc oxide, titanium dioxide, iron oxide, topical beta-carotene, vitamin C, vitamin E, ubiquinone (Coenzyme Q10) have been shown to protect against visible and infrared light.

Grape seed extract has been shown to be effective as an antioxidant, which prevents some of the damage to our skin cells that can result from sun exposure. Similarly, ferulic acid, vitamins C and E also have antioxidant properties.