Black Light Helps Diagnose Common Skin Problem Found in Pregnant Women

Researchers at BUSM and BMC have found that using a black light, or Wood’s light, helps dermatologists determine disease extent of melasma, a hyperpigmentation condition that causes brown and gray patches to appear on the face.

Melasma is most common among women, and often appears during pregnancy due to hormonal changes, leading many to refer to it as “the mask of pregnancy.” Most people notice skin discoloration on their cheeks, forehead, chin and bridge of their nose. The patches can also appear on parts of the body that are exposed to the sun like the arms and neck. When left undiagnosed, the brown and gray spots on the skin continue to darken and can alter a patient’s appearance and quality of life.

“In some cases, melasma can be very difficult to detect with the naked eye,” said Neelam Vashi, MD, assistant professor of dermatology at BUSM and director of the Center for Ethnic Skin at BMC and BU. “Using a black light allows us to assess the extent of the disease and counsel patients on sun protection measures and treatment options.”

A black light detects changes in color or fluorescence in the skin, making pigment disorders appear to shine under the light. It has been suggested as an aid in diagnosing melasma depth, but this is the first study to find a significant quantitative difference between viewing the skin under natural light versus under a black light when evaluating extent in those with subtle disease.

“Early detection is critical in treating this disease before it worsens. Without the use of a black light, the extent of the disease could go unnoticed and worsen over time with ultraviolet ray exposure or laser therapy. Treatment for melasma needs to be maintained, otherwise there is risk of the condition returning,” said Vashi.

Melasma treatments include topical creams, chemical peels, microdermabrasion, and sun protection. Researchers recommend that women protect themselves by applying sunblock every two hours when out in the sun or avoiding sun exposure altogether for those with a genetic predisposition, who are pregnant or have a known family history of melasma.