A study of dermoscopic features of nail psoriasis

Dermoscopy is a non-invasive imaging method that enables the evaluation of pigmented and non-pigmented skin lesions. More recently, dermoscopy has been recognized as an effective tool in the diagnosis of nail diseases.

To evaluate the dermoscopic features of nail psoriasis and to assess the relationship between these features and disease severity.

A total of 67 patients with clinically evident nail psoriasis (14 women, 53 men) were prospectively enrolled. Following a thorough clinical examination, patients were graded according to the Nail Psoriasis Severity Index and physician's global assessment score. A dermoscopic examination of all fingernails and toenails was performed using a videodermatoscope. Mann-Whitney U and χ² tests were used for statistical analysis, with a significance threshold of p < 0.05.

The most frequently observed dermoscopic features were splinter haemorrhage (73.1%), pitting (58.2%), distal onycholysis (55.2%), dilated hyponychial capillaries (35.8%) and the pseudo-fiber sign (34.3%). The pseudo-fiber sign, dilated hyponychial capillaries, nail plate thickening and crumbling, subungual hyperkeratosis, transverse grooves, trachyonychia, pitting and salmon patches were positively associated with disease severity.

The pseudo-fiber sign described in this study appears to be a novel dermoscopic feature of nail psoriasis. We have demonstrated positive associations between a number of dermoscopic manifestations and disease severity. Further studies are required to support the present findings.