Long FY, Zhang ZQ, He F, et al. - Researchers conducted this observational study to examine specific dermoscopic features of fingernail psoriasis and the relationship between the severity of nail lesions or systemic inflammation, and psoriasis severity of skin and nail. The sample consisted of 135 patients with fingernail psoriasis (1,186 fingernails) and 30 patients with onychomycosis (80 fingernails). The Nail Psoriasis Severity Index (NAPSI) score, Psoriasis Area and Severity Index (PASI) score, body surface area (BSA), and detailed history of patients with psoriasis have been recorded. The total NAPSI score was positively linked to the PASI score and BSA. The thumb's NAPSI score was higher than the other fingers'. Dermoscopic features can improve nail psoriasis diagnosis and have correlations with psoriasis severity.