Nail Dystrophy as a Predictive Marker for Psoriatic Arthritis: A Clinical, Ultrasonographic, and Microscopic Analysis

Résumé

Introduction: Nail psoriasis is a frequent and often debilitating manifestation of psoriasis, commonly associated with psoriatic arthritis (PsA). This study aimed to evaluate whether nail dystrophy serves as a reliable predictive marker for PsA. Methods: A cross-sectional study was conducted with 120 patients divided into four groups based on the presence or absence of nail dystrophy and PsA. Clinical assessments included NAPSI and PASI scores. Ultrasonographic examination (B-mode and Power Doppler) and microscopic analysis of nail clippings were performed to assess nail bed vascularization, nail plate thickness, presence of neutrophils, and transition zone integrity. Results: Nail dystrophy was observed in patients with and without PsA. There was no statistically significant difference in NAPSI scores between dystrophic groups. Multivariate logistic regression identified Power Doppler signal ≥ 2 as the strongest independent predictor of PsA (OR = 3.5; p = 0.002), followed by body mass index (BMI) (OR = 1.13; p = 0.015). Nail dystrophy did not remain statistically significant after adjustment (OR = 1.91; p = 0.07). Microscopic features, including neutrophilic infiltration and transition zone blurring, correlated with cutaneous psoriasis severity but not with PsA diagnosis.Conclusion: Although frequently present in PsA, nail dystrophy alone was not a specific predictive marker. Dynamic inflammatory parameters, such as increased nail bed vascularization on Power Doppler, and systemic factors like elevated BMI showed stronger associations with PsA. These findings highlight the need for integrated diagnostic approaches combining clinical, imaging, and systemic inflammatory markers to better stratify PsA risk in patients with psoriasis.