Ultrasonographic detection of subclinical enthesitis and synovitis: a possible stratification of psoriatic patients without clinical musculoskeletal involvement.

OBJECTIVES: To evaluate the prevalence of articular/extra-articular inflammatory lesions and structural damage on ultrasonography in patients suffering from psoriasis as well as to assess possible correlations between ultrasonographic elementary lesions and clinical features.

METHODS: Psoriatic patients without musculoskeletal symptoms and healthy controls (HCs) were recruited. All patients received a blinded extended ultrasonographic examination of 42 joints, 12 entheses and 32 tendons. Active synovitis was defined by the presence of a grade ≥2 for grey scale (GS) and ≥1 for power Doppler (PD), while active enthesitis corresponded to entheseal hypoecogenicity in GS and entheseal PD signal (<2 mm from bone insertion).

RESULTS: Forty psoriatic patients and 20 HCs were included. A total of 2516 joints and 712 entheses were scanned. Active synovitis was found in 11/40 (27.5%) psoriatic patients and 0/20 HCs (p=0.01). Articular synovitis (GS≥2) was more frequent in psoriasis than in HCs [34/40 (85.0%) and 11/20 (55.0%) respectively; p=0.024). Active enthesitis was found only in psoriatic patients, with a prevalence of 20.0% (8/40) (p=0.04). No significant difference in the prevalence of tenosynovitis or paratenonitis was observed between psoriatic patients and HCs. In psoriasis cohort, age was correlated with the presence of active synovitis (p=0.03), while male sex and a higher PASI score were independently correlated with the presence of active enthesitis (p=0.05 and p=0.034, respectively).

CONCLUSIONS: Active enthesitis and synovitis could be useful to identify subclinical psoriatic arthritis. This might represent a relevant clinical step to better stratify patients with psoriasis.