Dermoscopy of the nail bed and matrix to assess melanonychia striata.

Melanonychia striata represents a diagnostic dilemma for dermatologists. The use of dermoscopy to assess the nail has advantages over clinical examination. However, when compared to skin lesions, it gives fewer details. We describe two cases of melanonychia striata submitted to dermoscopic examination of the nail bed and matrix. This is a new procedure that enables observing dermoscopic characteristics that are not visualized in the nail plate, thus, providing additional information.