Double Nail of the Little Toe

Abstract

A rudimentary accessory or double nail of the little toe is not rare, although only described three times before. Most cases are accidentally detected and only few patients seek help because they have discomfort or pain. Some have a positive family history, but most patients cannot give any information concerning heredity. Clinically, the nail of the little toe is abnormally wide and is split or shows a longitudinal depression corresponding to a slight protuberance of the cuticle. Histopathology shows a complete though short nail. The treatment of choice is segmental excision of the entire accessory nail unit with mobilization of the lateral skin and primary suture.

Keywords: Accessory nail; Double nail; Histology; Little toenail; Nail unit resection.

Fig. 1

Little toes with double nail in a 36-year-old Portuguese woman. Note the callus at the lateral side of the middle interphalangeal joint.

Fig. 2

Both little toes with double nails in a 52-year-old Swiss woman who consulted us for retronychia.

Fig. 3

Asymmetric expression of the double little toenails: two individual right toenails and the typical left double nail adjacent to the main nail.

Fig. 4

A 39-year-old Swiss woman with bilateral double fifth toenails. The left little toe before segmental excision and 4 weeks after surgery is shown.

Fig. 5

Schematic illustration of the development of a symptomatic double toe and its treatment. a Patients with a splayfoot develop both a hallux valgus with internal as well as external rotation of the little toe. b Outward rotation makes the toenail being almost vertically positioned thus exerting symptoms similar to a corn upon pressure. c The excision line is drawn for the complete segmental removal of the accessory nail. Like in the big toenail, the lateral matrix horn reaches far proximal-laterally. d After the extirpation of the accessory nail, a little toenail of normal width is created.

Fig. 6

Double nail of the left fifth toe before and 3 weeks after surgical resection of the accessory part of the nail.

Fig. 7

Double nail of the left little toe before and 8 days after phenolization of the accessory nail.

Fig. 8

Histopathology of a poorly developed double nail (left) shows a shallow depression of the epidermis with eosinophilic hyperkeratosis and a pale area in the center representing nail substance, whereas a well-developed double nail (right) shows all characteristics of a normal little toenail with proximal nail fold and thick cuticle, matrix and very short but hyperplastic nail bed.