According to the American Cancer Society, 1 million Americans will develop skin cancer this year. The apparent precursor to cancer, actinic keratosis, occurs most often in the middle-aged to elderly, but especially in seniors with light skin and heavy exposure to sunlight.

Actinic keratoses are scaly patches that often appear on the face, neck, chest and back of the hands. Actinic refers to the ultraviolet light rays that produce chemical effects. A keratosis lesion is a sharply outlined, red or skin-colored scaly growth that can too easily turn into squamous cell carcinoma, a common type of skin cancer. Some types of cancers may look as innocuous as a bruise or blister; others can look and feel like eczema or psoriasis.

Elderly skin is particularly susceptible to sun damage due to thinning of the skin layers as the hormone levels decrease with age. Melanin—the protective coloration produced by melanocytes—generally guards our skin against ultraviolet rays. But as we age, melanin may be over- or under-produced, leaving hyper-pigmentation (darker spots) or hypo-pigmentation (whitish spots). Either way, the tan is uneven and the aging skin may appear shiny and splotchy.

Nicholas Perricone, M.D., in his book, The Perricone Prescription, discusses by skin colors the differences in skin response to sunlight. However, note that people of mixed heritage may look light skinned but may have characteristics typically associated with their darker-skinned relatives.

* The palest skin is that of Irish and Nordic types; this skin is the most susceptible to sun damage. Lack of melanin leads to early photo aging and wrinkling. In only five minutes of direct sunlight, damaging free radicals are activated and the cascade of sun damage begins. In addition, oil glands in light skin are less active, and the resulting dryness allows even greater free-radical production. This skin type needs a lifetime of protection every day by using sunscreen over moisturizer and under makeup.

* African American skin has more melanin and oil-gland activity and, therefore, more resistance to photo aging. However, use of strong soaps and toners against acne (often a problem for the dark skinned) can produce dryness that requires restorative use of a light, but nongreasy, moisturizer and sunscreen to prevent wrinkling.

* Asian skin tends to have enough melanin to resist photo aging, and the right level of oil-gland activity to resist chronic dryness and wrinkling. Sunscreen protection is still recommended.

* Latino skin has less melanin than the African American, but more than the Asian type. Oil-gland activity can protect against wrinkling but may cause acne; thus sunscreens and moisturizers need to be light and nongreasy.

The minimum recommendation for sunscreens is a sun-protection factor of 15, but some doctors prefer SPFs of 20 or 30. However, several Silicon Valley dermatologists have stated that the only effective methods of complete sun-blocking are wearing opaque clothing and spreading a layer of zinc oxide over exposed skin. Patients on certain medications (such as sulfa or high blood pressure drugs, or antibiotics) may experience photosensitive reactions that result in rashes or atopic dermatitis (itchy eczema) and may want to take these more-effective precautions.

Seniors should certainly stay in the shade when possible, avoid overhead sunlight between 10 a.m. and 2 p.m. and wear UV-protective sunglasses, in addition to sunscreen and opaque clothing.

A little extra anti-aging skin care can pay big dividends by also protecting against cancerous skin lesions. Brad Katchen, a New York dermatologist, recommends that men apply a moisturizing lotion that contains a sunblock of at least SPF 15 after shaving in the morning. "It's the best thing you can do to reduce both aging of the skin and skin cancer," he says. Moisturizing also plumps up skin cells and makes the face look better.

Perricone seems to agree. Preventing skin cancer means preventing aging skin, which means preventing the free radicals that produce damaging inflammation. "Whenever I looked at a disease under a microscope—everything from arthritis to heart disease—inflammation was always a component," he claims. Leading his list of inflammation causes is sun exposure.

Enjoy the sun, but be wary of too close a friendship.

REDUX: A reader of our last column on childhood diseases wrote that her husband's frightening breathing attacks were not diagnosed for many weeks until a lung specialist ordered a blood test: the husband had pertussis (whooping cough). She heard of two other seniors with similar symptoms and no diagnosis; she related her story, and they requested blood tests with the same confirmation: pertussis. Again, we have another juvenile disease dangerous to seniors and preventable by vaccination.