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Choice of Sunscreen Depends on Skin Type

May 19, 1991|HARRY NELSON

To stay safe in the vacation sun this summer, wear a hat and light-colored clothing and avoid midday sun. And don't forget a good sunscreen, which can provide important protection from ultraviolet radiation exposure.

As an article in the May issue of FDA Consumer Magazine says, "There's no such thing as a safe tan." Tans may look healthy, but they are outward indications that damage is taking place beneath the skin.

Skin cancer and premature skin aging are among the consequences of excessive exposure to ultraviolet (UV) radiation. In addition, UV can be a contributing factor in causing a lethal type of skin cancer called melanoma, the incidence of which is increasing.

More than 500,000 Americans will develop skin cancers this year, and some 8,500 will die--most of them from melanoma. Studies have shown that three or more blistering sunburns as a teen-ager is one of six factors that predict the development of melanoma. The others are blond or red hair, a family history of melanoma, outdoor summer work for more than three years as a teen-ager, actinic keratosis (pre-cancerous skin condition) and marked freckling on the back. Any one of these factors increases the risk 3.5 times. And when there is more than one factor, the risk is greater, depending upon which factors are present.

The average person receives 50% to 80% of lifetime sun exposure before the age of 18, and blistering sunburns occuring at this time increase the risk of skin cancer and melanoma. That makes it particularly important to protect children and teen-agers from overexposure to sun and also to wear sunscreens when possible. But which sunscreens offer the best protection?

Since 1978, the Food and Drug Administration has categorized sunscreens according to their sun protection factor (SPF). SPF numbers range from 2 to 50 and are marked on the package.

The appropriate SPF for an individual, according to the American Academy of Dermatology, depends on which of six skin types an individual has. The six types are skin: 1) that always burns easily and never tans, 2) of blue-eye and fair-hair Caucasians, 3) of darker Caucasians, 4) of Mediterranean Caucasians, 5) of some Latinos and 6) of some blacks, who are less sensitive to the effects of sunlight. The academy recommends that everybody use an SPF of at least 15, and that people with more sensitive skin use higher SPF values.

SPF numbers refer to a product's ability to block out UV radiation. A person who begins to turn red after 10 minutes in the sun without sunscreen, for example, could remain in the sun 150 minutes or 15 times longer if wearing an SPF 15 sunscreen.

There are exceptions to this rule, however. A sunscreen's resistance to sweat and water, the time of day (UV rays are more intense between 10 a.m. and 3 p.m.) and reflection off water, snow or sand may all be factors that limit protection. Some drugs, such as antihistamines, tricyclic antidepressants, diuretics and anti-cancer drugs increase sensitivity to the effects of ultraviolet light. People taking prescription drugs should consult their doctor before venturing out into the sun.

Although most health professionals agree on the need for sunscreen use, there is some disagreement as to which sunscreens are best. One subject of controversy has been PABA (para-aminobenzoic), the base used originally in sunscreens, and PABA esters, which contain glyceryl, padimate A and padimate O. One in 10,000 people are allergic to PABA and its esters. They react with itchy skin, a burning sensation and a red rash covered with tiny bumps where the product has been applied.

Some of those people can substitute bases called benzophenones (oxybenzone), cinnamates (octylmethyl cinnamate and cinoxate) or salicylates. There is no difference where sun protection is concerned.

Sunlight is composed of two types of ultraviolet light: UVA and UVB. Sunscreens work by absorbing UV radiation. The SPF factor refers largely to the UVB rays, which are those responsible for deep burns. UVA rays penetrate deeper into the base layer of the skin than UVB rays and are responsible for skin wrinkling and aging. Both UVB and UVA rays contribute to skin cancer, but there is no FDA-approved rating system to identify UVA protection.

For protection against both UVA and UVB rays, some doctors recommend sunscreens that contain a combination of padimate O plus oxybenzone or padimate O plus Parsol. A report two years ago suggested that padimate O may produce a chemical called nitrosamine, which might be cancer-causing, but the FDA says the report has not been confirmed and says there is no reason to avoid using the compound.

So-called waterproof sunscreens tend to be more expensive and, despite their claim, tend to wash away and need to be reapplied, though not as often as gels and lotions. Gels sweat off and wash off more easily than other sunscreens, but may be preferable for those who are acne-prone. Gels need to be reapplied frequently.

No matter how good sunscreens are today, they are not as protective as opaque substances such as zinc oxide, which many people find to be visually unattractive. A good combination, then, could be to use zinc oxide on the bridge of the nose, the tops of the ears and back of the neck and a regular sunscreen elsewhere.

Consumers can expect to get the kind of protection that the labeling specifies, according to an FDA statement. The agency recommends finding something that feels comfortable--a gel, lotion or cream--and applying it daily 20 to 30 minutes before going out. Many cosmetics today also contain sunscreens.

The agency also recommends only using tanning products listing an SPF factor.

Doctors recommend that sunscreens containing PABA or PABA esters not be used on children under six months of age. Also, on small children it is best to avoid using lotions containing alcohol because they may cause eye irritation.

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