Diagnostic Considerations
Clouston syndrome (hidrotic ectodermal dysplasia)
Patients with this syndrome are born with nails, but then lose them. These patients exhibit patchy alopecia as well as a clinical triad of onychodystrophy, generalized hypotrichosis, and palmoplantar keratoderma. [15] They lack the radiographic abnormalities of the distal phalanges found in patients with congenital onychodystrophy of the index finger (COIF).
Congenital anonychia
Unlike patients with congenital onychodystrophy of the index finger, patients with congenital anonychia lack skeletal abnormalities of the distal phalanges.
Fetal antiepileptic drugs (AEDs) syndrome
Patients with this syndrome have major malformations, minor anomalies, microcephaly, cognitive impairment, cleft lip and/or cleft palate, heart defects, growth retardation, midface hypoplasia, hypoplasia of the fingers. The physical features of infants exposed to various anticonvulsant drugs are not the same.
Nail-patella syndrome
One third of patients with nail-patella syndrome have abnormalities limited to just the thumbnails, one third have abnormalities of the thumbnails and other selected nails, and one third have abnormalities of all fingernails.
Poland syndrome
Distinguishing features of this syndrome are a congenital absence of the pectoralis major muscle on the ipsilateral side of the digits displaying congenital onychodystrophy of the index finger–like findings.
DOOR syndrome
Individuals can have congenital onychodystrophy and no related findings. However, identification of vestigial nails (onychodystrophy) is crucial for the correct diagnosis of DOOR (deafness, onychodystrophy, osteodystrophy, and mental retardation) syndrome. [16]
Olmsted syndrome
This is a rare congenital skin disorder characterized by severe palmoplantar and periorificial keratoderma, alopecia, onychodystrophy, and severe pruritus. This is a slow, progressive disease without satisfactory treatment. [17]
Differential Diagnoses
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Micronychia of the left index finger and malalignment of the nail of the middle finger. Courtesy of Veterans Administration Puget Sound Health Care System.
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Y-shaped bifurcation of the distal phalanx of the left index finger in the lateral view. Courtesy of Veterans Administration Puget Sound Health Care System.
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Y-shaped bifurcation of the distal phalanx of the right index finger in the lateral view. Courtesy of Veterans Administration Puget Sound Health Care System.
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This infant illustrates the typical presentation of congenital onychodysplasia of the index finger (COIF). Examination of the right index finger reveals micronychia. The changes of the left index finger approach anonychia except for the presence of a small amount of dystrophic nail. Courtesy of Dr. Ilene Rothman.
