Pigment abnormalities mark photoaged skin

National report - Pigmentary changes in skin are one of the first indicators of photoaging, according to Neil Sadick, M.D., F.A.C.P.

"The prevalence of photoaging-associated pigmentary changes is very high," Dr. Sadick says. "More than 90 percent of people with evidence of photoaged skin have freckles, melasma-like changes or lentigines. Pigmentary changes are part of the photoaging triad, which also includes wrinkling and irregular coarseness of the skin." Dr. Sadick is clinical professor of dermatology, Weill Cornell Medical College, New York.

According to Dr. Sadick, discrete areas of discoloration (e.g., lentigines) develop in the skin when melanocytes are activated by increased exposure to ultraviolet light (UV) and geneticfactors. The mechanism for this melanocytic upregulation is unknown.

Risk factors In addition to sun exposure and genetics, risk factors for pigmentary changes include birth control pills and certain medications such as tetracycline derivatives, particularly Minocin (Lederle), according to Dr. Sadick.

"Medications can either stimulate melanocytes or they can form drug complexes with melanocytes," he says. "These changes don't go away when the (causative) drug is withdrawn, and can be permanent unless treated." Dark-skinned people such as blacks have more pigment dyschromias than do light-skinned people, he adds.

Although pigmentary changes only harm patients in a cosmetic sense physically, they can lead to psychological withdrawal and can interfere with interpersonal relationships, according to Dr. Sadick. Patients who seek treatment include young people with a genetic predisposition and dark skin. Women who have used birth control pills chronically or have had significant UV exposure (or both) also ask for treatment.

Treatment options "For diffuse pigmentary changes, people can try OTC medications such as 2 percent hydroquinone, hydroquinone retinoid, or hydroquinone-retinoid-steroid creams," Dr. Sadick says. "Then we move on toprescription hydroquinone at 4 to 6 percent, retinoid derivatives and combinations, the most popular combination product being Lustra (Medicis). We can also give at-home regimens that include increasing (monthly) concentrations of alpha hydroxy acid, beginning at 5 percent and getting up to 40 percent, compounded with hydroquinone from 4 to 5 percent. Then we introduce a retinoid derivative such as tazarotene at another time during the day."

To treat diffuse hyperpigmentation, Dr. Sadick and his colleagues are trying salicylic acid or beta peels combined with microdermabrasion.

"We like using superficial peeling agents, microdermabrasion, and either Electro-Optical Synergy (ELOS, Syneron) or intense pulsed light (IPL)," he says. "ELOS is a unique technology that combines optical and radiofrequency energies. Our electron microscopic studies show we can shatter the melanosomes with ELOS."

For lentigines, the best treatment is with Q-switched lasers - ruby, alexandrite or neodymium:YAG, he adds.

To avoid long-term pigmentary changes of photoaging, Dr. Sadick advises patients to minimize UV exposure at an early age, and to wear sunblock that protects them from both short-wavelength UV-B and long-wavelength UV-A light. If patients have a genetic tendency toward pigmentation, Dr. Sadick suggests that they think twice about using birth control pills, associated with a high incidence of pigmentary changes.

Disclosure: Dr. Sadick reports no financial interest in any of the products described.