The family physician (FP) recognized that this was a case of longitudinal melanonychia (LM) from racial melanosis with pseudo-Hutchinson’s sign. (The real Hutchinson’s sign is the presence of dark pigment on the proximal nail fold in conjunction with melanoma of the nail unit.)
The FP told the patient that no treatment was needed, but that if the nail pigment started to change or one line became increasingly dark or wide, she should come in for further evaluation. LM is more common in darkly pigmented individuals. It occurs in 77% of African Americans older than 20 years and in almost all of those older than 50 years. It also occurs in 10% to 20% of people who are of Japanese descent, and is common in the Hispanic population. LM is unusual in Caucasians.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Mayeaux EJ. Pigmented nail disorders. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. The Color Atlas of Family Medicine. New York, NY: McGraw-Hill; 2009: 822-825.
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