Role of nail biopsy as a diagnostic tool.

Nail biopsy (NB) is an investigation that is not routinely resorted to by most of the dermatologists. The commonly cited reasons are the complexity of the procedure, risk of scarring and the reluctance of the patient. However, in cases with isolated nail psoriasis, isolated nail lichen planus, onychomycosis not confirmed on direct microscopy and culture, or longitudinal melanonychia, the treating dermatologist is left with no choice but to resort to this procedure. Nail as a unit, is capable of projecting only a limited number of clinical manifestations. This is responsible for the more or less similar clinical presentation of many different nail disorders. Hence, a practical knowledge of the indications, appropriate patient selection, procedural details and histopathological interpretation of a NB is a must-have for any practicing dermatologist. The risk of scarring is none to minimal if appropriate type of biopsy is performed, not to mention the wealth of histopathological data that can be retrieved from the nail unit. This article aims to explore the various practical do's and don'ts for the NB and tells us what to expect from of the procedure.