Big Sky, Big Burn

When the American Medical Association met in Dallas last week for its annual winter clinical sessions, the sun shone brilliantly if coolly over what Texans call the "Land of the Big Sky." But big sky and bright sun are far from being an unmixed blessing, warned Houston's Dr. John M. Knox, a dermatology professor at Baylor University College of Medicine. Along with other skin specialists in the Southwest, he is seeing more and more harmful effects from exposure to the sun, now that leisure time is increasing and proportionately more of it is spent in "healthy" outdoor activity (and, he might have added, by bathers and sunbathers wearing proportionately less clothing.)

Skin cancer from exposure of the face, neck and hands to sun and wind was first described by Germany's Paul G. Unna in 1894 as Seemanns-haut. A dozen years later, William Dubreuilh made an observational refinement in the Bordeaux vineyards : women got skin cancer on the parts of their faces left exposed by their scarves, while men got it on the back of the neck. In the U.S., 91% of skin cancer is on the hands, face and neck, 2% is on "occasionally exposed" sites, and 6.5% on sites never ordinarily exposed.

Skin Screen. An individual's risk of harmful consequences, ranging from sunburn to cancer, is in inverse ratio to the density of the screen built into his own skin--the amount of pigment in the epidermis. This is most clearly shown, said Dr. Knox, in the contrast between the albino Negro, who has no tolerance whatever for the sun's tanning and burning rays, and the normal Negro, who has a high degree of tolerance, increasing with the darkness of his skin.

Aside from albinos, the most susceptible sun victims are redheads and blondes. Ironically, Dr. Knox noted, fair-skinned people, who are usually most anxious for a tan, run the greatest risk in the process. Olive-skinned people, who run less risk, do not need the tan anyway. (Blonde women, Dr. Knox added unchivalrously, show their age more than brunettes--mainly because of the obvious aging effects of sunlight on their skin.)

Chemical Screen. Popular suntan lotions and creams increase tolerance to light rays by factors of four to six, said Dr. Knox. A cream containing one of the best chemical screens known, para-amino-benzoic acid, will increase it a hundredfold. So .will the newest chemical sunscreen family, the benzophenones. Trouble with benzophenones is that they absorb all rays at the spectrum's blue end--including those needed for a fashionable tan. So Dr. Knox suggested that redheads and others with exceptionally fair skins who do not want to freckle use a shutout benzophenone preparation. Others less sensitive may use a para-aminobenzoic acid preparation, which will pass rays to provide a safe tan.

It is time, concluded Dr. Knox, for the medical profession to begin an educational campaign on the harmful effects of excess exposure to sun, and advocate use of preparations to ward off both premature aging of the skin and cancer. Blondes, he suggested, can keep that schoolgirl complexion longer if they use powder and makeup bases with built-in chemical sun screens. It was with no hint of boasting that Dallas' Dr. James B. Howell noted: "Texans have the highest incidence of skin cancer in the population of any state."

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