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Dermoscopy of nail pigmentations

Antonella Tosti, MD
Section Editor
Hensin Tsao, MD, PhD
Deputy Editor
Rosamaria Corona, MD, DSc


Nail pigmentation is most commonly caused by deposits of melanin or hemosiderin within the nail plate. It is rarely due to deposits of other pigments of endogenous or exogenous origin.

Melanin deposits result from activation or proliferation of nail matrix melanocytes and in most cases present as a longitudinal pigmented band called longitudinal melanonychia or melanonychia striata [1].

Nail dermoscopy (onychoscopy) can greatly improve the differential diagnosis of nail pigmentation and helps clinicians with at least minimal training in dermoscopy to distinguish benign lesions, which do not require additional examinations, from lesions that require excision for pathologic evaluation or regular follow-up [2,3].

However, dermoscopy should not be considered a substitute for pathology in the differential diagnosis of doubtful cases of longitudinal melanonychia [4]. This topic will discuss the causes of nail pigmentation and the dermoscopic evaluation of benign and malignant pigmented nail lesions. Nail disorders are discussed separately. The dermoscopic evaluation of cutaneous and mucosal lesions is also discussed separately. Dermoscopic algorithms for skin cancer triage are also discussed separately.

(See "Overview of nail disorders".)

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Literature review current through: Nov 2017. | This topic last updated: Aug 01, 2016.
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