Quadrant-Based Comparison of Ultraviolet-Fluorescence Dermoscopy, Standard Dermoscopy, and Clinical Examination in Adults with Nail Psoriasis: A Prospective Pilot Study of 35 Patients.

INTRODUCTION

Accurate visualization of nail-matrix psoriasis remains challenging. Ultraviolet-fluorescence dermoscopy (UVF-D) may enhance detection, yet rigorous comparative data are scarce. The aim of this study was to compare the diagnostic yield of UVF-D with standard dermoscopy and naked-eye clinical examination for matrix and bed involvement in nail psoriasis.

METHODS

In this single-centre prospective pilot study (March-July 2024), 35 consecutive adults with plaque psoriasis underwent triplicate assessment (clinical, dermoscopy, UVF-D) of all fingernails. Each nail quadrant was scored for matrix-Nail Psoriasis Severity Index (NAPSI) and bed-NAPSI by two blinded dermatologists in randomized order. The study was powered (80%, α = 0.05) to detect a ≥3-point mean difference in matrix-NAPSI between modalities.

RESULTS

UVF-D identified matrix involvement in 550/1,400 quadrants (39.3%) versus 448/1,400 (32.0%) with standard dermoscopy and 441/1,400 (31.5%) clinically (p < 0.001; Kendall's W = 0.42). Mean ± SD matrix-NAPSI scores were 15.7 ± 5.3 (UVF-D), 12.8 ± 5.2 (dermoscopy), and 12.6 ± 4.8 (clinical). Thus, UVF-D detected roughly one additional matrix-affected quadrant for every seven examined and produced a higher matrix-NAPSI, underscoring its added sensitivity over conventional methods.

CONCLUSIONS

UVF-D significantly improves visualization of nail-matrix psoriasis versus standard approaches. Larger multicentre studies should validate its diagnostic and longitudinal utility.