A study of dermoscopic features of nail psoriasis

Abstract

Introduction: 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.

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

Material and methods: 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.

Results: 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.

Conclusions: 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.

Keywords: dermoscopy; nail; pseudo-fiber sign; psoriasis; severity.

Figure 1

Longitudinal fusiform splinter haemorrhages, distal onycholysis, salmon patches (20×)

Figure 2

Serpentine-like splinter haemorrhages (green arrows), pitting and distal onycholysis (20×)

Figure 3

Pitting (20×)

Figure 4

Salmon patch (20×)

Figure 5

Pitting with a leukonychic appearance (blue arrows), note the artificial staining (20×)

Figure 6

Pseudo-fiber sign along the cuticle (40×)

Figure 7

Closer view of Figure 6 (100×)

Figure 8

Pseudo-fiber sign underneath the distal free edge on the hyponychium (40×)

Figure 9

Red and black filamentous structures under the distal free edge (yellow arrows), note the visible hyponychial capillaries (purple arrows) (40×)

Figure 10

Red and black filamentous structures visible over the nail plate, evident distal nail bed capillaries (40×)

Figure 11

Pseudo-fiber sign, evident distal nail bed capillaries (60×)

Figure 12

Pseudo-fiber sign in areas of shedding (30×)

Figure 13

Filamentous structures on denuded nail bed area (40×)

Figure 14

Pseudo-fiber sign, interwoven capillaries (red arrow) (30×)

Figure 15

Filamentous (blue arrow) and zigzag shaped (pink arrow) structures, note the two colours in one structure (yellow star) corresponding to the arterial and venous ends of a capillary remnant (100×)

Figure 16

Filamentous structures (green arrow) and pinpoint dots (purple arrows) (80×)

Figure 17

Filamentous structures emerging beneath the cuticle (100×)