Encourage your teen to avoid solar radiation between 10 A.M. and 4 P.M. 
This is when the ultraviolet rays are the harshest. The safest measure—stay indoors or seek shade—isn’t always practical. Next best? Protect that skin by wearing the proper clothing and sunscreen.
Light-colored, tightly woven clothing
Light-colored, tightly woven clothing reflects sunlight rather than absorbs it. A hat with a brim at least three inches wide also affords protection.
Get your teen into the habit of applying sunscreen
And not just when she goes to the beach and not just on bright, sunny days. Even when clouds obscure the sun, 80 percent of its UV light reaches the earth. You can singe your skin during the winter, too, since snow reflects 80 percent of the sun’s rays.
Sunscreens used to be classified according to their sun protection strength, which was expressed as a Sun Protection Factor (SPF) ranging from 2 to 50. The higher the number, the longer the user can stay in the sun without burning. So let’s say that your youngster typically burns in about fifteen minutes. A sunblock with an SPF of 15 would afford him 225 minutes (just under four hours) of safe exposure. If he is dark-complexioned and generally doesn’t burn for, say, forty minutes, the same product would enable him to spend six hundred worry-free minutes outdoors.
Having said that, no one should bake in the sun for that long, regardless of how much sunscreen he slathers on his skin. The U.S. Food and Drug Administration has since pared down the categories to just three strengths: minimum (which corresponds to 2 SPF to 12 SPF), moderate (12 SPF to 30 SPF) and high (30 SPF or greater). Moderate strength is the sensible choice for most people.
Memo to Mom and Dad: Before purchasing sunscreen, look for the words “broad-spectrum” on the label; this assures you that the product screens out both types of ultraviolet light: UVA and UVB. UVA radiation doesn’t burn skin as readily as UVB—and the jury is still out on whether or not it contributes to skin cancer—but we do know that UVA rays penetrate tissue more deeply and age the skin.
Buying sunscreen is the first step; using it correctly is the second
Studies show than most sun worshipers use only about one-fifth to one-half as much sunscreen as they should. To thoroughly cover the entire body—including the ears and hands, which most people neglect—the general rule of thumb is to apply about one ounce of water-resistant lotion or cream fifteen to thirty minutes before going outdoors. Then generously reapply every two hours and immediately after swimming or strenuous activities.
Protect the eyes too
According to the American Optometric Association, sunglasses should block out 99 to 100 percent of both UVA and UVB radiation and screen out 75 to 90 percent of visible light. Gray, green or brown lenses work best.
The American Academy of Dermatology recommends that teens periodically inspect their bodies for suspicious-looking moles
To do this, they’ll need a full-length mirror, a hand mirror, and a well-lit room.
- Standing in front of the full-length mirror, examine the front and back of the body. Then, with arms raised, do the same for the left side and the right side.
- Bend both elbows and carefully inspect the forearms, the back of the upper arms, and the palms of the hands.
- Next, look at the backs of the legs and the feet, the spaces between toes, and the soles of the feet.
- Hold up the hand mirror and examine the back of the neck and the scalp. Part hair to lift.
- Finally, check the back and the buttocks with the hand mirror.
- If you spot any unusual-looking moles, immediately make an appointment with your pediatrician. Skin cancers are eminently treatable when caught early.