Incomplete development of the hallux nail.

Abstract

The incomplete development of the nail of the big toe, known in the literature under the name of hypertrophy of skin folds of the hallux (2), is the most frequent nail alteration of the newborn, found in over half the cases (1). The toenail appears triangular or trapezoidal at birth and lateral skin folds partially cover the nail. However, after 2-3 months the nail takes on a normal appearance. For this reason it is believed that this neonatal nail alteration is a paraphysiological condition, due to the particular slowness of growth of the nail of the big toe and the increased speed of growth of the nail plate in its central portion as compared with the side ones. Therefore, the apparent hypertrophy of the lateral skin folds is only secondary to the lacking pressure on them by the nail plate.