Photo Rounds

Darkened skin on neck

A 47-year-old Hispanic woman sought care for darkening of the skin around her neck. For the past 10 years, the family physician (FP) had been treating the patient’s type 2 diabetes with metformin. Her diabetes was moderately controlled, however the patient had gained 10 pounds in the previous year.

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The FP recognized the dark velvety skin as acanthosis nigricans. He also noted multiple skin tags (acrochordons) on the patient’s neck. The patient requested that the skin tags be removed and wanted to know what could be done about the dark color on her neck. She was worried that it looked dirty.

The FP suggested that the patient increase her efforts at weight loss through improved diet and increased exercise. The patient was willing to work on weight loss, but still wanted something to decrease the skin hyperpigmentation. The FP prescribed topical tretinoin cream 0.025% to be applied before bed. Other treatment options for the acanthosis nigricans include keratolytic agents (eg, salicylic acid, ammonium lactate) and topical vitamin D analogs.

Before the visit was over, the FP snipped off the skin tags with a sharp iris scissor and stopped the bleeding with topical aluminum chloride.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Smith M. Acanthosis nigricans. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. The Color Atlas of Family Medicine. New York, NY: McGraw-Hill; 2009:942-944

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