Clinical Analysis of Nail Involvement in Psoriasis and Psoriatic Arthritis

Background: It has been reported that nail psoriasis is common in psoriatic arthritis (PsA) patients, however, studies on the prevalence of PsA with nail psoriasis and the relationship between the severity of the diseases has not previously been reported in Korea. Objective: The aim of this study was to investigate nail psoriasis and its relation to psoriasis and PsA. Methods: After researching past medical records, 48 patients with nail psoriasis and 247 patients without nail psoriasis were enrolled in this study. Nail psoriasis was classified according to the morphologic types of nails and severity was evaluated using the modified nail psoriasis severity score index (mNAPSI). We assessed the severity of psoriasis and PsA by psoriasis area and severity index (PASI), and swollen and tender joint counts (STJC), respectively. Finally, we analyzed the relationship between mNAPSI, PASI, and STJC. Results: Nail involvement was observed in 48 (16.3%) of 295 patients. Prevalence of PsA was higher in nail psoriasis (31.3%) than in uncomplicated psoriasis (9.3%, p���0.001). mNAPSI showed a positive correlation with STJC (p=0.002, Pearson correlation=0.427), but not with PASI (p=0.094, Pearson correlation=0.202). Conclusion: The results show that PsA is more common and severe in psoriatic patients with nail involvement than in uncomplicated psoriasis. Clinicians should be alert to nail involvement in psoriatic patients, as it could be related to the disease course and prognosis of PsA