[Sandy nails and twenty-nail dystrophy of childhood. Apropos of 2 cases].

2 apparently idiopathic cases of twenty-nail dystrophy of childhood are reported with follow-ups of 4 and 16 years, respectively. The associated koilonychia appears to be only fortuitous and related to the fragility of the nail. Trachyonychia should be considered as a symptom often related to external traumatism or dermatoses, particularly alopecia areata or lichen planus, of which it could be a specific isolated location. Within the spectrum of apparently idiopathic trachyonychies , the twenty-nail dystrophy of childhood appears to be a real entity on the basis of its clinical features and course.