Abstract: Objective: To explore the correlation between nail psoriasis and subclinical extensor tendon enthesitis in psoriasis. Method: Extensor tendons at the distal interphalangeal joints and fingernails of both hands were detected by high frequency ultrasound in the patients with psoriasis. Result: A total of 96 psoriasis patients were included in this study: 45 patients with nail involvement and 51 patients without nail involvement. Sixteen patients (35.5%) had subclinical enthesitis in the nail psoriasis group and five (9.8%) had subclinical enthesitis in the normal nail group, with a significant difference (P <0.01). Conclusion: Psoriatic nail can be used as a sign for the screening of subclinical extensor tendon enthesitis.

Key words: psoriasis, enthesitis, high frequency ultrasound