Given the clinical presentation and the absence of other systemic or dermatological findings, the diagnosis of chevron nails was made.
Discussion
The condition is characterized by transverse ridges on the nails that converge towards the center, forming a V or chevron shape. This condition was first described by Perry et al. and later by Shuster et al., who explained that the condition might result from axial growth of the nail with synchronous growth occurring from a chevron-shaped growing edge of the nail root. Alternatively, Shuster suggested that sequential growth, with localized variation in the nail production rate, could propagate a wave from the center of the nail to the edge.
The etiology of chevron nails is not well understood, but it is believed to result from temporary disruptions in the nail matrix, possibly related to minor illness or physiological stress during infancy.
In the case of our 7-month-old patient, the history of mild upper respiratory infections might have contributed to the development of chevron nails. However, the lack of other significant illness, skin involvement, or systemic findings supports the benign and self-limiting nature of this condition. Parents were reassured that chevron nails typically resolve on their own as the child grows and that no specific treatment is necessary.
Differential Diagnosis
The differential diagnosis of transverse nail changes in children includes other conditions such as trachyonychia, lichen planus, Darier disease, and pachyonychia congenita.
Trachyonychia, also known as “sandpaper nails,” trachyonychia is characterized by the roughening of the nail surface, giving it a dull and ridged appearance. The condition may affect all 20 nails and is often associated with underlying dermatological conditions such as lichen planus or alopecia areata. Unlike chevron nails, trachyonychia presents with more diffuse nail changes and does not typically feature the distinct V-shaped ridging seen in this patient.
Lichen planus is an inflammatory condition that can affect the skin, mucous membranes, and nails. Nail involvement in lichen planus can lead to longitudinal ridging, thinning, and sometimes even complete nail loss. The absence of other characteristic features of lichen planus, such as violaceous papules on the skin or white lacy patterns on mucous membranes (Wickham striae), makes this diagnosis less likely in our patient.
Darier disease, also known as keratosis follicularis, is a genetic disorder characterized by greasy, warty papules primarily on seborrheic areas of the skin, nail abnormalities, and sometimes mucosal involvement. Nail changes in Darier disease include longitudinal red and white streaks, V-shaped notching at the free edge of the nails, and subungual hyperkeratosis. These nail changes are more severe and distinct than the simple transverse ridging seen in chevron nails. The absence of other clinical signs of Darier disease, such as skin papules or characteristic nail notching, makes this diagnosis unlikely in our patient.
Pachyonychia congenita is a rare genetic disorder characterized by thickened nails (pachyonychia), painful plantar keratoderma, and sometimes oral leukokeratosis. The condition typically presents with significant nail thickening and other systemic findings, which were absent in our patient. The distinct pattern of V-shaped ridging observed in chevron nails does not align with the typical presentation of pachyonychia congenita.