Longitudinal nail biopsy: Utility in 20-nail dystrophy

BACKGROUND. Twenty-nail dystrophy (TND) is an inflammatory disorder of the nail unit. It is frequently encountered in childhood and is believed to be a common clinical manifestation of several nail pathologies. Varying associations and histopathologic features have been reported previously. OBJECTIVES. To evaluate the clinical and histopathologic profile of TND and the utility of longitudinal nail biopsy (LNB) for the same. METHODS. Thirty-two consecutive patients with TND were screened clinically. The histopathologic features of skin and longitudinal nail biopsies were also evaluated. The efficacy of nail unit biopsy was thereby assessed. RESULTS. Young males in the 10- to 20-year-old age group were most commonly affected (52%). Alopecia areata was the most commonly associated dermatosis (22%). LNB revealed a specific diagnosis of either psoriasis or lichen planus in 52% of the cases, whereas the rest showed nonspecific histologic changes (spongiotic trachyonychia). Scarring was a major risk associated with LNB, as evident in 28% of the patients studied. CONCLUSIONS. These data reveal the clinical profile and common associations of TND. They also confirm the diagnostic utility of nail biopsy in TND patients and advocate this procedure in cases in which the clinical diagnosis is otherwise obscure. However, it cannot be recommended in the routine evaluation of patients with a relatively benign disorder such as TND. Furthermore, nail biopsy is proven to be a relatively simple and useful procedure.