RESUMO
BACKGROUND: Scoring systems are indispensable in evaluating the severity of disease and monitoring treatment response. OBJECTIVE: We sought to evaluate the competence of various nail psoriasis severity scoring systems and to develop a new scoring system. METHODS: The authors conducted a prospective, observational, single-point study of 36 patients given the diagnosis of fingernail psoriasis. Seven scoring systems were evaluated: Nail Psoriasis Severity Index (NAPSI), modified NAPSI, target NAPSI, Psoriasis Nail Severity Score, Nail Area Severity, Baran, and Cannavò et al. All tools were correlated with the Physician Global Assessment. Obtained information was integrated into the Nijmegen-Nail psoriasis Activity Index tooL (N-NAIL), and interrater and intrarater reliability was assessed. RESULTS: Physician Global Assessment showed an acceptable correlation with the scoring system designed by Baran (r = 0.735, P < .01) and the Psoriasis Nail Severity Score (r = 0.734, P < .01). Target NAPSI showed low correlation (r = 0.203, P > .05). The correlation between Physician Global Assessment and the N-NAIL was 0.861 (P < .01). Excellent agreement was found for the intrarater and interrater reliability of the N-NAIL. LIMITATIONS: Sample size was limited. CONCLUSION: An adequate nail psoriasis scoring system is needed, as studies of treatments for nail psoriasis are on the horizon. Clinical severity of nail psoriasis was best reflected by the N-NAIL, followed by the Baran system and the Psoriasis Nail Severity Score.