Hypertrichosis Is Not so Prevalent in Becker's Nevus: Analysis of 47 Cases.

Becker's nevus is a relatively common cutaneous hamartoma, but is often overlooked or misdiagnosed. This nevus usually begins during the second decade of life as a circumscribed, hyperpigmented patch with irregular outline that gradually enlarges with associated hypertrichosis, developing several years later. The purpose of this study was to determine the prevalence of lesional hypertrichosis associated with Becker's nevus. Methods. 47 patients who had sharply demarcated brown patch with or without coarse hair, presence or enlargement of the lesion at the time of puberty, and compatible Wood's light examination were enrolled. Patients who had axillary freckling, previous skin inflammation, and gray pigmentation of the lesions were excluded. Results. In summary, the mean age of onset was 11.89 (range 0-19). The most commonly involved site was the arm (34%), followed by shoulder (23.4%), chest, face, flank, buttock, and leg. Lesional hypertrichosis was found in only 8 (17%) of the 47 patients. In 29 cases (61.7%) the lesions were in the right side of the body. Conclusion. Hypertrichosis was not so frequent among patients with Becker's nevus. There was a higher preponderance of the lesions on the right side.