Median Canaliform Dystrophy of Heller is considered as a relatively rare nail disorder, especially in children. This term was first described by Heller in 1928 and is characterized by a single central longitudinal cleft with transverse ridges that approximate a fir tree [1]. This disorder is essentially symmetrical and affects more frequently the thumb nails than the other fingers, which is the case of our patient, with a bilateral localization at the level of the two big toes [2]. The precise cause of this nail disorder poses an etiological problem for dermatologists as it is not yet determined. The most common theory is that of repeated rubbing of the nail in the proximal fold and the underlying matrix, but other diagnoses must be eliminated, notably a glomus tumor, myxoid tumor and other tumors reported in the literature [3,4]. Some studies report familial occurrences of median nail dystrophy, one study also showed a temporal association with oral isotretinoin treatment with improvement on discontinuation of treatment and an association with dental disease and macrolunule [5,6]. We have found a case report of an 11-year-old girl who developed ductal dystrophy after using periungual cryotherapy for treatment of warts [7]. The treatment of median ductal dystrophy is still far from satisfactory. If a patient suffers from obsessive-compulsive disorder or impulse control disorder and suffers from a habitual tic, a psychiatric opinion is sought with behavioral therapies. However, treatment with tacrolimus 0.1% topical ointment resulted in a considerable improvement in the appearance of the nail plate [4]. The originality of our observation lies in the rarity of Median Canaliform Dystrophy of Heller in children, especially in the toes, as it usually affects the thumb. The presence of a possible onychodystrophy should therefore be treated as a real psychotherapeutic emergency and parents should be warned of the importance of a careful examination of their children's nails.