Q&A: Removing or lightening dark patches of skin?

I’m a 63-year-old woman with several dark brown patches of skin on my face that won’t go away. Is there some cream or lotion that can lighten or remove them? —Name withheld, Portland, Ore.

Some treatments may lighten them but probably won’t remove them. The most likely cause of that darkening is overproduction of pigment by skin cells—usually triggered by increased levels of the hormone estrogen during pregnancy or while taking oral contraceptives or hormone-replacement therapy. But your doctor should also rule out other possible causes, such as an allergic reaction to a drug, including certain antibiotics, antiseizure and psychiatric drugs, and diuretics; and underlying conditions such as hyperthyroidism and certain nutritional deficiencies.

Stopping an offending drug or treating an underlying condition probably won’t cause the patches to fade, but they may be lightened somewhat by using a nonprescription bleaching cream containing hydroquinone (Black & White Bleaching Cream, Esoterica), either alone or together with a prescription exfoliating cream such as azelaic acid (Azelex) or tretinoin (Renova).