Nail manifestations in Hong Kong Chinese patients with psoriatic arthropathy (PsA)

Abstract Background Nail psoriasis is accepted as a common feature in psoriatic arthropathy (PsA) and is one of the diagnostic criteria for PsA. Several nail characteristics are allegedly associated with joint damage, however, information concerning their prevalence and features is extremely lacking, particularly in Hong Kong. Objective The primary objective of the study was to investigate the frequency of psoriatic nail disease and to understand their patterns. The secondary objective was to explore the associated factor for nail dystrophy among them. Methods This study was a cross-sectional observation study. The eligible PsA patients were recruited from Rheumatology Clinic of Tseung Kwan O Hospital. Their demographics and clinical characteristics were collected, their respective nail psoriasis were scored and the nail features were recorded. By comparing the clinical variables between PsA patients, with and without nail involvement, the associated factor was explored. Results A total of 106 PsA patients were recruited and 61.3% (65/106) of them had nail psoriasis. Among all the patients with nail involvement, 72.3% of them had pitting, 50.8% had onycholysis, 15.7 had crumbling, 6.9% had leukonychia and 3.9% suffered from nail-bed hyperkeratosis, with mean modified Nail Psoriasis Severity Index of 9.5 +/-15.3. Nail involvement was more common in those with severe skin extent, but neither related to psoriatic disease duration, arthritis subclasses, nor inflammatory markers. Conclusion A significant proportion of PsA patients had nail involvement and there were various nail features noted. The occurrence of psoriatic nail disease was found to be associated with severe skin problem. This common manifestation of PsA should not be overlooked in the rheumatologists’ daily practice, in view of its common prevalence.