Double little toenails: Report of 4 familial cases

Double nail of the second toe: A case report with sonographic and radiological correlation

“…Accessory toenails or double toenails are a rare type of onychodysplasia. 1 There are several reports in the literature about accessory nails of the fifth toe. However, to our knowledge, a double nail of the second toe has not been reported in the literature.…”

“…Traditionally, double toenails have been considered a genetic disorder with autosomal dominant inheritance, present at birth or early childhood. 1 Any ethnic group and both sexes can be affected.…”

“…2,3 Congenital double toenails may represent an incomplete form of polydactyly, with some of these cases associated with a Y-shaped bone abnormality in the underlying distal phalanx. [1][2][3] Polydactyly of the toes are divided into preaxial (hallux), postaxial (fifth toe), and mesoaxial (second to fourth toes), the latter being the rarest. Generally, polydactyly is isolated and can go unnoticed or manifest only with nail alterations.…”

“…In the latter, induction of specialized nail mesenchyme or the division of the nail matrix can occur secondary to trauma. 1,5 Congenital double toenails should also be differentiated from ectopic nails, cutaneous horns, nail fibrokeratomas, onychophosis, and acquired calluses. 1,2 Ectopic toenails are rare and are usually located on the palmar surfaces of the fingers.…”

Onychoheterotopia in children

“… 4 Three zones constitute EN: nail matrix, nail bed, nail plate, similar onycholysis, but differently arranged compared to a standard nail. 5 The EN has a matrix in the center or back, with a horizontal-vertical growth pattern and a distal or inverted orientation. The neo-nail is generally conical and spatulashaped at dermoscopic presentation, looking like a rudimentary fingernail with a corrugated surface and transverse furrows.…”