Page 7 - Mecklenburg_Medicine_May-2019

Feature

TBy Patricia K. Roddey, MD, Medical Director of Dermatology, Tryon Medical Partners Consumer Reports conducts tests on sunscreens in its laboratories.
hose of us who have an opportunity to remind people to In the latest rating published May 2018, Consumer Reports found
protect their skin from the sun should do so. Current national mineral sunscreens — those that contain only titanium dioxide,
statistics estimate the incidence of skin cancer at one in five

Americans (or 20 percent). The occurrence of the deadliest zinc oxide, or both as active ingredients — tended to underperform

form of skin cancer, melanoma, can be attributed to ultraviolet light compared to those that have chemical active ingredients, such as

exposure, both natural and artificial. The level of risk in an individual is avobenzone. In fact, none of the mineral sunscreens in the tests did

directly related to the cumulative level of ultraviolet exposure, regardless of well enough to make the ratings list.

age or skin type. Regarding sunscreen ratings, it is worth reviewing sunscreen

• The first rule of thumb regarding sun exposure: Avoid sun designation terms. The SPF (Sun Protection Factor) test measures

exposure between the hours of 10 a.m. and 4 p.m. when the sun’s rays the amount of UV radiation exposure it takes to cause sunburn when

are the strongest. Stay in the shade and wear protective clothing. Choose sunscreen is in use compared to how much UV exposure it takes to

clothing with a tight weave that cannot be seen through when held up to cause sunburn when sunscreen is not used. For example, if a sunscreen

light. Don’t forget to wear a broad-brimmed hat. is rated as SPF 15, that would mean that use would cause it to take

• If activities require sun exposure during the hours of strong 15 times longer for the skin to burn than if not using the sunscreen.

rays: Apply sunscreen 15 or 20 minutes before going outside. Be sure Because SPF values represent the product’s level of sunburn protection,

to shake the bottle to distribute the active ingredients evenly. For lotions, they are primarily, though not exclusively, an indicator of expected

use a shot glass full to cover your face, neck, trunk and extremities. For protection from UVB radiation, which is the part of the light spectrum

application of sprays to the face, it is best done by spraying it in the hand that causes sunburn. SPF 30 sunscreen blocks 97 percent of UVB rays,

and then rubbing it on the face. For the rest of the body, apply as much as SPF 50 blocks 98 percent and SPF 100 blocks 99 percent.

can be rubbed in, then repeat. Uneven application with sprays results in To be labeled broad spectrum per the FDA, sunscreen products must

areas of sunburn. Regardless of whether lotion or spray is chosen, reapply demonstrate that they provide UVA protection in addition to UVB

every two hours and immediately after sweating or getting out of the water. protection. Only products that prove both to provide broad spectrum

• Choosing sunscreen: The FDA just proposed a new protection and to have a minimum SPF of 15 have been shown to

regulation in February aimed at making sure sunscreens are safe reduce the risk of skin cancer and early skin aging caused by the sun,

and effective. They are currently asking for comments on the when used as directed with other sun protection measures. By contrast,

proposal. It is found on the FDA website at www.federalregister.gov/ sunscreens that have not been demonstrated to provide both broad

documents/2019/02/26/2019-03019/sunscreen-drug-products-for-over- spectrum protection and an SPF value of at least 15 only have been

the-counter-human-use. demonstrated to help prevent sunburn, and not specifically skin cancer

Currently, only two active ingredients are considered proven safe by and the signs of aging skin, such as brown spots, fine wrinkles, loss of

the FDA, thus they are in Category I, due to available data supporting elasticity and roughness.

that they comply with GRASE (general recognition of safety and The new proposal by the FDA requires encouraging consumers to

effectiveness). These two ingredients are zinc oxide and titanium use a broad-spectrum SPF 15 or higher product, regularly use sunscreen

dioxide, the agents known as physical or mineral blockers. They can and apply it liberally 15 minutes before sun exposure and at least

be in concentrations up to 25 percent in sunscreens in compliance

with FDA standards. Other current ingredients in sunscreens — the

so-called chemical agents — cinoxate, dioxybenzone, ensulizole,

homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate

O, sulisobenzone, oxybenzone, or avobenzone, would be categorized as

Category III in the proposal because insufficient data exists to declare

them as Category I. PABA and trolamine salicylate data suggest the

risks of using them in sunscreen products outweigh the benefits, so they

are proposed to be placed in Category II.

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