Dactylitis, one of the most typical features of psoriatic arthritis (PsA), is the diffuse swelling of the digits and is determined by the involvement of different anatomic structures, including: the subcutaneous fibrous tissue “accessory pulley” system; flexor tendons, with their related structures; the articular synovium; the small enthesis of the hands. Dactylitis is currently considered both a marker of disease activity and severe prognosis and its importance in PsA is emphasized by the inclusion in the classification criteria of PsA. This review focuses on the role of imaging in the management of PsA patients with dactylitis in clinical practice and in a research setting. Furthermore, imaging could be a valuable tool to assist in unravelling some of the underlying mechanisms of the onset and chronicization of dactylitis in PsA patients.

Polymyalgia rheumatica (PMR) is one of the most common rheumatic inflammatory disorders in people aged over 50. It is characterized by aching and prolonged morning stiffness in the shoulder and pelvic girdles and neck. To date there are no specific diagnostic tests, and in clinical practice the diagnosis of PMR remains based on its characteristic clinical manifestations, laboratory evidence of systemic inflammation, rapid response to low doses of glucocorticoids and exclusion of other disorders that may present with proximal pain and stiffness. For classification purposes, several criteria have been proposed over time based on retrospective clinical series, but none have been validated and received universal acceptance. Recently, an international collaborative initiative between the EULAR and the ACR was undertaken to develop new polymyalgia rheumatica classification criteria. In this review, the provisional 2012 EULAR/ACR classification criteria will be presented and their contribution for the diagnosis of polymyalgia rheumatica will be discussed.

In psoriatic arthritis (PsA) patients with concomitant chronic widespread pain, the differential diagnosis with fibromyalgia syndrome (FMS) can be challenging. We evaluated whether ultrasound (US) examination of entheseal sites can distinguish pain from (PsA) enthesitis versus FMS. PsA and FMS patients underwent clinical evaluation and gray-scale (GS; B-mode) and power Doppler (PD) US examination of the entheses. At least one enthesis with GS- and PD-mode changes was found in 90% and 59.3% of PsA patients (n = 140) and 62.7% and 35.3% of FMS patients (n = 51), respectively. GS and PD identified changes in 49.5% and 19.2% of the 840 PsA entheses and 22.5% and 7.9% of the 306 FMS entheses, respectively. Receiver operating characteristic curve analysis showed an area under the curve of 0.77 and 0.66 for B- and PD-mode, respectively, 3.5 being the best cut-off GS-score to discriminate the two conditions. Multivariate regression showed that Achilles and proximal patellar tendon enthesitis (B-mode) were strongly associated with PsA (odds ratio, ~2). Principal component analysis (B-mode) confirmed that PsA patients have a higher number of involved entheses and patterns of entheseal involvement than FMS patients. US evaluation of the entheses may help differentiate chronic widespread pain from PsA versus FMS.

This observational and prospective study evaluated the clinical correlations of sonographic lesions in consecutive psoriatic arthritis (PsA) dactylitis cases. Eighty-three dactylitic digits were evaluated clinically and sonographically before treatment and at one-month (T1) and three-month (T3) follow-up. Clinical evaluation included the Leeds Dactylitis Index-basic (LDI-b) score and the visual analogue scales for pain (VAS-p) and functional impairment (VAS-FI). High-frequency ultrasound with grey scale (GS) and power Doppler (PD) assessed flexor tenosynovitis (FT), soft tissue oedema (STO), extensor tendon paratenonitis, and joint synovitis. There was a statistically significant correlation between the clinical parameters (VAS-p, VAS-FI, and LDI-b) and FT and STO at T1 and T3. We found statistically significant improvement in FT and STO for the cases with clinically meaningful treatment responses (p < 0.001). After a multiple conditional logistic regression analysis, the only variables that correlated with a T1 clinical response were the resolutions of PD FT (OR 15.66) and PD STO (OR 6.23), while the resolution of PD FT (OR 27.77) and of GS STO (OR 7.29) correlated with a T3 clinical response. The clinical improvements of active dactylitis are linked to the regression of sonographic evidence of extracapsular inflammation (particularly FT and STO).

Background/Objectives: Patients with acute anterior uveitis (AAU) have a high prevalence of occult spondyloarthropathy (SpA). Only one previous study investigated ultrasonographic (US) changes at peripheral entheses and joints in patients with acute anterior uveitis (AAU) and no study has used these data in recognizing unknown SpA as defined by ASAS criteria. No previous study compared non-granulomatous (NGAU) with granulomatous uveitis (GAU) for these US features. The objective of this study was to investigate the prevalence of US enthesis and joint abnormalities in a consecutive series of GAU and NGAU patients and to use these data in recognizing unknown SpA as defined by ASAS criteria. Methods: A total of 152 consecutive patients diagnosed with AAU [103 NGAU (42 B27−, 61 B27+) and 49 GAU] from the Immunology Eye Unit (AUSL-IRCCS Reggio Emilia, Italy) were enrolled in this study. Six peripheral entheses as well as knee and ankle joints were bilaterally evaluated by US according to standard methods. The presence of any elementary lesion, structural damage and active enthesitis, according to OMERACT definitions, was recorded. ASAS classification criteria of SpA were integrated with the US data of active enthesitis and joint synovitis in defining the presence of enthesitis and arthritis. Results: NGAU patients had a higher prevalence of entheseal erosions (11.9% vs. 9%, P0 0.009), of enthesis exhibiting a PD signal (29.7% vs. 12.2%, p = 0.025) and of active enthesitis (23% vs. 8.2%, p = 0.026) compared with GAU group. Unknown SpA as defined by ASAS criteria was recognized in 29 patients by clinical and MR/Rx examination of sacroiliac joints and in 13 additional patients with the use of US data. Conclusions: Acute entheseal lesions and erosions are associated with NGAU, without apparent influence of HLA-B27 positivity. US examination helps to recognize previously unknown SpA and to define the disease phenotype of patients, moving toward more personalized treatment.

Background: In psoriatic arthritis (PsA), clinical tenderness and ultrasound (US) capture distinct yet related aspects of entheseal disease activity. However, their longitudinal relationship after initiation of biologic disease-modifying antirheumatic drugs (bDMARDs), and the clinical significance of early discordance during follow-up remain unclear. Methods: In this retrospective observational cohort study based on routinely collected medical records, patients with CASPAR-defined PsA and clinically and ultrasonographically active enthesitis at baseline (Clin+/US+) who initiated bDMARD therapy underwent paired, same-day, blinded clinical and US assessments at approximately 6 and 12 months. Agreement between clinical and US findings was quantified using Cohen’s kappa. Discordant states (Clin−/US+ and Clin+/US−) were prespecified, and predictors of Clin−/US+ status at 6 months were analyzed using models that accounted for within-patient clustering. Results: Thirty-nine patients contributed 82 entheses and were treated with either tumour necrosis factor inhibitors (53.8%) or interleukin-17 inhibitors (46.2%). At 6 months, agreement between clinical and US assessments was fair (κ = 0.286; 95% confidence interval [CI], 0.080 to 0.492), with 23.2% of entheses classified as Clin−/US+ and 52.4% as concordantly inactive. At 12 months, agreement improved to substantial-to-almost-perfect levels (κ = 0.779; 95% CI, 0.595 to 0.963), with only 1.2% of entheses remaining Clin−/US+ and 80.5% achieving concordant remission. NSAID exposure was the only significant predictor of Clin−/US+ status at 6 months in univariable analysis (odds ratio [OR], 3.82; 95% CI, 1.27 to 11.47; p = 0.017) and remained associated after multivariable adjustment (OR, 6.16; 95% CI, 1.14 to 33.2; p = 0.03). Conclusions: In PsA patients starting bDMARD therapy, clinical and US assessments of enthesitis showed partial discordance at 6 months, followed by greater convergence at 12 months. These findings suggest that clinical and imaging abnormalities may resolve asynchronously during follow-up and should therefore be interpreted in an integrated, time-aware manner. Residual US abnormalities in the setting of clinical improvement should be interpreted cautiously and within the broader clinical context.