Skin spots signs of sun damage

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— Have you ever seen a brown spot on your skin and wondered what it was? Sun kisses scattered over the nose of a red-haired child are readily identified as freckles, but other spots can be more difficult to categorize without experience -- or a biopsy.

Dark areas of skin are usually the result of an increase in the pigment produced by melanocytes, the cells that produce melanin. Most pigmentation is the result of genetic control or exposure to ultraviolet light. Diseases, pregnancy, drugs or enzyme deficiencies also may alter pigmentation.

Several types of excessive pigmentation (referred to as hyperpigmentation) can be seen in humans. Freckles are areas where the melanocytes are more active and responsive to UV radiation than in neighboring skin. Freckles, associated with fair hair and skin, tend to be more pronounced in childhood.

Age or liver spots, called lentigines, are small, flat, dark brown or black spots. These most often occur in sun-exposed skin sometime after the age of 40. They frequently occur on the neck, face and backs of hands. These spots are the result of years of sun exposure, not your age or liver function. They represent an increase in the number of damaged melanocytes.

Seborrheic keratoses are rough, oval or round patches, beige or brown in color, that seem to be "stuck on." These barnacles start to appear in middle age and increase in number with time.

Pregnancy-related or hormone-related hyperpigmentation, called melasma, causes blotches of pigmentation on the face or in sun-exposed areas of the skin. It is more common among people with light brown skin, especially Hispanics and Asians. The increased pigmentation is due to the influence of estrogen, progesterone and melanocyte-stimulating hormones. Patches tend to darken in the sun but fade after the exposure to hormones is reduced or eliminated.

Acne scars, bug bites, burns, surgical scars and even rashes may leave dark spots that linger after the skin has healed. This post-inflammatory discoloration tends to be darker on the torso and lower body than the face. The darker your skin, the more prone you are to this type of hyperpigmentation.

If you experience hyperpigmentation and do not know the cause, it is best to have it examined by your doctor. Most brown spots can be easily diagnosed with visual inspection. A sample of tissue -- called a biopsy -- may be necessary for microscopic evaluation if the diagnosis is uncertain.

Your skin type, the cause of the hyperpigmentation and how quickly you want improvement usually guide the specific treatment. Cryotherapy, a treatment that uses liquid nitrogen, can be an effective and rapid fix for isolated areas.

More diffuse areas of pigmentation may improve with prolonged use of creams that produce a bleaching effect. This is accomplished either by increasing cell turnover or inhibiting melanin production. Some examples of these creams are tretinoic acid (commonly called Retin-A), hydroquinones, glycolic acid and kojic acid.

Chemical peels, either as a series of superficial peels or one medium-depth peel, and various lasers may produce a more rapid, dramatic improvement.

Your best treatment for many forms of hyperpigmentation is prevention. Use a broad-spectrum sunscreen, preferably one that contains zinc oxide. Wear a broad-brimmed hat and protective clothing that is specifically formulated to block UV rays. Avoid tanning beds. Recognize that there is no such thing as a "healthy tan," unless it comes from a bottle.

Maryann Wall, M.D., F.A.C.S., of Northwest Colorado Ear, Nose, Throat & Facial Plastic Surgery, is board-certified in both otolaryngology and facial plastic and reconstructive surgery.

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