A Correlation Study Of Nail Psoriasis And Subclinical Extensor Tendon Enthesitis

Background:Psoriatic arthritis(PsA)is a chronic and disabling arthropathy,and the incidence is about 20~30%in psoriasis,early diagnosis and treatment of which can prevent the progress of articular symptoms.From the rheumatological perspective,the presence of nail disease is a predictor for the development of psoriatic arthritis and histopathology shows that nail is closely linked to the distal interphalangeal joint by extensor tendon.Therefore,some scholars have suggested that whether nail paoriasis could be a clinical clue for subclinical enthesitis.Nail involvement is a common manifestation both in psoriasis and PsA.However,the assessment of the severity of the nail is mainly based on the clinical scoring system,which can only evaluate the changes of the nail plate but not the nail bed and the nail matrix.As ultrasonography has high resolution and penetration,we assessed the utility of it for the nail involvement in the study.Objective:To explore the correlation between nail involvement and subclincal extensor tendon enthesitis in psoriasis without arthiritis and assess the utility of ultrasonography for the nail involvement.Methods:Physical examinations were performed with psoriasis patients without arthritis symptoms in our hospital.They are grouped according to whether with nail involvement or without.All extensor tendons at the distal interphalangeal joints of both hands were examined by ultrasonography in all psoriasis.Extensor tendon enthesitis were assessed and the thickness of nail plate,nail matrix and nail bed were measured,χ~2 test was used to compare the results of the two groups.Results:A total of 96 psoriasis patients without arthritis symptoms were included in this study,with 45 patients with nail involvement and 51 patients with normal nails.There were no significant differences between the two groups when considering the gender,age,disease duration and PASI scores.21 patients(21.8%)had subclinical extensor tendon enthesitis,of which 16 cases(35.5%)with nail involvement compared to 5(9.8%)individuals with normal nails,and the difference was statistically significant(P=0.002,P<0.01).Ultrasonography showed that the thicknesses of nail matrix and bed were both significantly higher in patients with nail involvement(1.66 vs.1.52,P<0.001;1.75 vs.1.47,P<0.001)whereas nail plate thickness were similar(0.70 vs.0.70,P=0.85).Conclusion:The nail psoriasis was associated with subclinical extensor tendon enthesitis;ultrasonography can effectively evaluate the nail psoriasis.