Pachyonychia congenita (PC) is a rare autosomal-dominant keratinisation disorder, primarily presenting with nail dystrophy, palmoplantar keratoderma, oral leucokeratosis and follicular hyperkeratoses. Nail changes in PC are often misdiagnosed. Dermoscopy, as a non-invasive diagnostic tool, enhances the visualisation of nail morphology but its application in PC remains underreported. This case series describes three patients with PC who underwent detailed clinical, dermoscopic and laboratory evaluations. Onychoscopic examination revealed several consistent features across cases, including obliteration of the lunula, nail plate thickening, pale proximal nail plate with brownish distal discolouration and compact subungual hyperkeratosis. Additional findings such as onychorrhexis, onychogryphosis and anonychia were variably present. One case demonstrated severe 20-nail involvement, possibly correlating with specific keratin mutations; while in contrast, the other two cases had milder nail changes, underscoring phenotypic variability. These observations suggest that onychoscopy can assist in early and accurate diagnosis of PC, aiding differentiation from other nail dystrophies. To our knowledge, this is one of the first case series describing onychoscopic features of PC in detail. Further large-scale studies are needed to validate these findings and establish potential genotype-phenotype correlations.
Dua et al. (Tue,) studied this question.