Freckles on an 8-year-old nose are cute. Brown spots on the back of a grown-up hand are not. For those who would as soon forgo this badge of maturity, there are lotions, creams and dermatologists.

For the most part, they threaten nothing but vanity. The flat brown areas, rarely larger than a quarter, that first appear in the thirties and increase through middle and old age, are usually "lentigines," produced when skin pigment cells -- melanocytes -- grow in number. They are usually benign -- and stay that way.

According to Tufts University dermatologist Barbara Gilchrest, a few decades' worth of sunshine stimulate some. But for age spots in covered areas, there's nothing to blame but biology.

"We usually imagine that the skin slows down and turns off as we age," says Dr. Gilchrest, "but there's also a growth regulation disturbance, which makes certain cells proliferate."

New York dermatologist Norman Orentreich cautions that lentigines should not be confused with light brown "solar keratoses," areas of sun-thickened skin that may turn malignant in time. Early stages of malignant melanoma -- the worst of skin cancers -- can also get lost in the crowd of age spots.

"If a spot is raised, crusted or inflamed; if it bleeds or its color is irregular or changed, see a dermatologist," urges Dr. Orentreich.

What to do about garden-variety age spots is a matter best left between the bearer and his or her self-image. If you want them gone, most dermatologists will freeze them away virtually painlessly.

For those in no hurry, there's the chemical route. Prescription bleaching creams and lotions contain chemicals such as hydroquinone, which penetrate the skin and curtail pigment production. Use them twice daily for six weeks and the spots will probably get lighter, says Gilchrest.

Over-the-counter lotions contain the same ingredients but in far weaker doses. "The spots might get a little lighter after a few months," she says.

How to keep age spots away altogether or discourage new ones? The only way, says Gilchrest, is with a sunscreen.