Dermoscopic Features of Nail Psoriasis: An Observational, Analytical Study

Abstract

Introduction: Nail involvement in psoriasis occurs in up to 30–50% of patients, and 5–10% may have isolated nail disease. Onychoscopy, a noninvasive tool, might obviate the need for nail biopsy, which is a diagnostic gold standard. Objective: The aim of this study was to evaluate onychoscopic features of nail unit in patients with nail psoriasis. Methods: Fifty-five patients with clinically diagnosed and histologically documented nail psoriasis were recruited. Onychoscopy was performed for each nail (excluding the 5th toenail). Clinically, 443/550 fingernails and 101/440 toenails were involved. The frequency distributions of various onychoscopic features was assessed and compared using the χ² test (p value <0.05 was considered significant). Results: With onychoscopy, additional 52 fingernails and 64 toenails showed psoriatic involvement. Pitting was the commonest finding in fingernails (60.5%) followed by subungual hyperkeratosis (SUH) (52.8%), onycholysis (40.8%), and dotted capillaries in hyponychium, proximal, and lateral nail folds (38.6 vs. 35.8 vs. 35.8%). In toenails, we observed SUH (85.1%), nail plate thickening (82.1%), onycholysis (77.2%), and dotted capillaries in hyponychium and nail folds (59.4 vs. 53.4 vs. 45.5%). Fuzzy lunula was a novel onychoscopic finding noted in 33.6% fingernails and 4.95% toenails (p < 0.00001). Limitations: Small sample size. Conclusions: Onychoscopy may aid in diagnosing nail lesions even before the clinical signs are apparent.