Symptomatic psoriatic dactylitis is associated with ultrasound determined extra-synovial inflammatory features and shorter disease duration

Early psoriatic arthritis: clinical and therapeutic challenges

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic immunoinflammatory disease of the enthesis and adjacent synovium, skin, and nail, which early diagnosis may be crucial for starting a prompt therapeutic intervention. Theoretically, early treatment offers the advantage of acting on the reduction of the articular damage progression since initial phases of the disease.

AREAS COVERED

This review explores the challenges of clinical-diagnostic aspects and the underlying pathophysiology of early PsA phases, as well as the evidence evaluating the impact of early intervention on disease outcomes.

EXPERT OPINION

Main instruments for early PsA diagnosis include recognizing synovial-entheseal inflammatory signs at onset, improving screening PsA high-risk subjects, and increasing disease knowledge of physicians and patients with psoriasis or familial history.PsA continues to significantly impact on the Quality of Life of patients affected by the disease, making necessary to deeply study clinical manifestations, risk factors and underlying immunoinflammatory mechanisms, as well as to identify biomarkers for early identification. Additionally, it remains a need to increase more evidence on understanding how early treatment of PsA and of psoriasis might influence the course of the disease.

High-resolution ultrasound imaging of elementary lesions in dactylitis

OBJECTIVE

The aim of the present study was to illustrate the (potential) diagnostic role of high resolution US images in assessing the elementary lesions of dactylitis.

METHODS

Using high-frequency US machines/probes, we matched the micro-anatomical cadaveric architecture of the digit with multiple sonographic findings of dactylitis. High-sensitive color/power Doppler assessments have also been performed to evaluate the digital microvasculature.

DISCUSSION

Modern US equipment/features guarantee prompt and in-depth B-mode and color/power Doppler imaging of tiny anatomical structures of the digit which are usually not properly visible with standard US machines. More specifically, hypervascularization of the digital subcutaneous tissue, fibrous pulleys of flexor tendons, dorsal synovial pads as well as pathological changes of the distal entheseal anchorage network can be accurately detected.

CONCLUSION

In clinical practice, high-end US equipment can be used to accurately assess the digits in patients with dactylitis. This way, simple and convenient sonographic diagnosis of different elementary lesions can be timely established.

Recent developments for new investigational JAK inhibitors in psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic inflammatory disease affecting about one-third of subjects with psoriasis. Several treatment modalities targeting Janus Kinase pathways and intracellular inflammatory cascade are now available and under clinical investigation to treat this disease.

AREAS COVERED

This review describes ongoing and recently completed phase 2 and 3 Randomized Clinical Trials (RCTs) evaluating the efficacy and safety of approved JAK (Tofacitinib and Upadacitinib) and investigational JAK inhibitors (JAK1 inhibitors: Filgotinib and Ivarmacitinib (SHR0302); TYK2 inhibitors: Brepocitinib (PF-06700841) Deucravacitinib (BMS-986165), and NDI-034858) in PsA through February 2023.

EXPERT OPINION

Current standard of care has significantly improved the quality of life in PsA. Recently approved JAK inhibitors for PsA have addressed many of the unmet needs of PsA, particularly of those with severe phenotypes. Preliminary results from several RCTs have reported good and fast efficacy and an acceptable safety profile of investigational JAK inhibitors in PsA. Additional clinical trials and long-term outcome data on these agents are necessary for increasing available therapeutic options for PsA.

How Variable Is the Volar Subcutaneous Tissue of the Digits on B-Mode and Color Doppler Ultrasound in Non-Psoriatic Individuals and Could It Be Included in a Dactylitis Score?

BACKGROUND

 Digital subcutaneous tissue (SCT) changes are involved in dactylitis, a hallmark feature of psoriatic arthritis (PsA). There are no studies on the ultrasound (US) characteristics of the digital SCT in the general population.

OBJECTIVES

 To investigate the variability in US-measured thickness (TH) and color Doppler (CD)-detected blood flow of the SCT of the volar aspects of the fingers in a non-psoriatic population and to investigate the impact of the scanning method and demographics and clinical features on these measurements.

METHODS

 SCT TH and semiquantitative (SQD) and quantitative (QD) Doppler signals were measured in the bilateral second finger at the proximal and middle phalanges in 81 non-psoriatic volunteers [49 female, 32 men; 18-78 years]. Two scanning methods with and without (thick gel layer interposition) probe-skin contact were used. Demographics and clinical features were collected.

RESULTS

 There was high variability of SCT TH and Doppler measurements between individuals. All US measurements obtained without probe-skin contact were significantly greater than their corresponding measurements obtained with the probe contacting the skin (p < 0.001). SCT TH was positively related to dominant hand, age, masculine gender, weight, height, body mass index, and alcohol consumption while Doppler measurements were positively related to age and non-dominant hand.

CONCLUSIONS

 US-measured SCT thickness and Doppler-detected SCT blood flow of the volar aspect of the fingers seem to be highly variable in the non-psoriatic population as well as highly dependent on the US scanning method. This variability is of utmost importance for assessing dactylitis in PsA.

New Perspectives on Diagnosing Psoriatic Arthritis by Imaging Techniques

Psoriatic arthritis is a chronic inflammatory condition that can lead to severe functional impairment and irreversible damage. The diagnosis can be difficult in early cases where the clinical exam is often scarce. The lack of a serological biomarker can lead to a considerable delay in diagnosis. In this review, we discuss the existent imaging methods that have improved the diagnosis of psoriatic arthritis (PsA). The degree and type of musculoskeletal involvement cannot be assessed by only one imaging method. We think that a combination of methods is the best approach to evaluate both structural damage and inflammatory lesions and that ultrasound (US) could be the best tool to screen a patient when considering the diagnosis of PsA. US is an accessible, non-ionizing technique that offers information regarding active inflammation in joints, entheses, and soft tissues.

Ultrasound Effectiveness of Steroid Injection for hand Psoriatic Dactylitis: Results from a Longitudinal Observational Study

Introduction

To assess clinical and ultrasound effectiveness of steroid injection (local treatment, LT) into the digital flexor tendon sheath for the treatment of psoriatic dactylitis compared to systemic treatment (ST) alone.

Methods

In this observational, multicentre, prospective study, 88 cases of symptomatic hand dactylitis were evaluated clinically and sonographically by high-frequency ultrasound (US) probe in both greyscale (GS) and power Doppler (PD). The presence of flexor tenosynovitis (FT), soft tissue oedema (STO), peritendon extensor inflammation and synovitis was assessed (including DACtylitis glObal Sonographic—DACTOS—score) before treatment, at 1-month (T1) and 3-months (T3) follow-up. LT was proposed to all patients. Patients refusing LT were treated with oral NSAIDs. Patients continued the same baseline csDMARDs and/or corticosteroid therapy during the whole follow-up period. US response was defined for DACTOS score < 3 and US remission for DACTOS score = 0.

Results

At T3 evaluation the ST group showed a significantly higher persistence (grade > 1) of FT and STO (p < 0.001 for all) and MCP synovitis (p = 0.001). US remission was achieved only in the LT group (at T3 31% vs. 0, p < 0.001). The percentage of patients with DACTOS < 3 was significantly greater in the LT group compared with ST group, at both T1 (49% vs. 5%, p < 0.001) and T3 evaluation (76% vs. 7%, p < 0.001). In multiple conditional logistic regression analysis, the only factor associated with US remission was LT (T3 odds ratio = 41.21, p < 0.001).

Conclusions

US confirmed the effectiveness of steroid injection for dactylitis by demonstrating that it involves the resolution of extra-articular inflammation, in particular FT and STO.

Psoriatic Dactylitis: Current Perspectives and New Insights in Ultrasonography and Magnetic Resonance Imaging

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.

Power Doppler enhancement of accessory pulleys confirming disease localization in psoriatic dactylitis

OBJECTIVE

The digital accessory pulleys are highly mechanically stressed mini-entheses that are thickened in patients with a history of PsA-related dactylits. This study explored whether these pulleys are involved in PsA dactylitis as assessed by intra-pulley US power Doppler changes.

METHODS

Fifty-eight PsA patients with dactylitis had US of the second to fourth digits for pulleys of the dactylitic and contralateral digits. The Leeds Dactylometer was used for thickness measurement. The presence of digital pain, tenderness, and swelling in the dactylitis finger and in the contralateral side was evaluated.

RESULTS

We recruited 34 patients with acute and 24 patients with chronic dactylitis, 45/58 (77%) of which had tenderness on clinical assessment. Intra-pulley power Doppler was more frequently found in the dactylitic digits compared with contralateral sides and linked to A1, A2 and A4 pulleys thickening [power Doppler signals in A1 pulley (51%), A2 (22%) and A4 (12%) in dactylitic digit; compared with 1 A1, A2 and A4 pulleys each in the contralateral side (1.7%)]. Almost all cases had peri-tendinous oedema, and 82.6% of dactylitic digits had flexor tenosynovitis with power Doppler signals in 65.2% of flexor tendons.

CONCLUSION

Despite their small size and relatively avascular, the accessory pulleys exhibit power Doppler change in active Psoriatic dactylitis, supporting a pivotal role in dactylitis-related tenosynovitis and extra-tendinous disease.

Sensitivity to change and clinical correlations of the novel DACtylitis glObal Sonographic (DACTOS) score in psoriatic arthritis

OBJECTIVE

The aim of the study is to assess the performance of the DACTOS (DACtylitis glObal Sonographic) score in a PsA dactylitis clinical setting. In particular, we evaluated the ability of DACTOS to identify the affected fingers, its sensitivity to change after treatment, the correlations between DACTOS and clinical parameters, and the capacity of the score to identify the treatment responders.

METHODS

Forty-six consecutive patients with symptomatic PsA hand dactylitis were enrolled. A total of seventy-three dactylitic digits were evaluated clinically and sonographically before and after treatment in this observational and prospective study. Clinical assessment included the Leeds Dactylitis Index-basic (LDI-b) score and visual analogue scales for pain (VAS-p) and functional impairment (VAS-FI). Sonographic lesions were investigated using high-frequency ultrasound with grey scale and power Doppler features according to the DACTOS score. Correlations between the DACTOS score and the clinical parameters were assessed at baseline, 1 month (T1) and 3 months (T3).

RESULTS

We observed significant improvements in all of the assessed clinical parameters and the DACTOS scores after dactylitis treatment. There was a statistically significant correlation between the variation of all clinical parameters (VAS-p, VAS-FI and LDI-b) and the DACTOS score at T1 and T3 evaluations. We found statistically significant differences in the DACTOS score between clinical responder and non-responder groups (P < 0.001) and between clinical remission and non-remission groups (P < 0.001).

CONCLUSION

The DACTOS score performs well in real-life clinical settings in terms of sensitivity to change and correlations with clinical features in PsA dactylitis.

Experimental and Investigational Pharmacotherapy for Psoriatic Arthritis: Drugs of the Future

In recent years, different studies have shown in psoriatic arthritis (PsA), the pathogenetic role of multiple cytokines other than tumor necrosis factor-α, such as interleukin-17 (IL-17), and IL-23 and dysfunction of Janus kinase (JAK)-signal family pathway. These molecules also represent the target of recently developed biologic (bDMARDs) and targeted synthetic disease modifying antirheumatic drugs (DMARDs) (tsDMARDs) currently investigated in several Phase II and III randomized controlled trials (RCTs). This review examines the therapeutic efficacy and safety of most recent developed IL-17, IL-23 and JAK inhibitors and highlights how these new PsA therapies are going to revolutionize the management of PsA in the next few years. Ongoing RCTs of these molecules in PsA are also described. Available literature on new anti-IL-17 and anti-IL-23 agents and JAK inhibitors demonstrates the potential role of these molecules as effective therapeutic strategies across multiple PsA clinical domains, along with an acceptable tolerability and safety profile, thus expanding the treatment options available for PsA patients. Of note, other molecules are under investigation, and among those, potential therapeutic strategies seem to be represented by single antibodies blocking simultaneously two cytokines, the agents inhibiting mammalian target of rapamycin (mTOR), receptor retinoic acid receptor-related orphan receptor gamma (RORγt), A3 adenosine receptor (A3 AR), and K⁺ channel voltage channel inhibitors. Remarkable progress has been made in PsA pharmacotherapy, and novel bDMARDs targeting IL17A and tsDMARDs (JAK-inhibitors) represent promising therapies. More clinical trials are needed to better characterize the efficacy and safety profile of these therapeutic agents in PsA treatment.

Musculoskeletal Ultrasound in Monitoring Clinical Response to Treatment in Acute Symptomatic Psoriatic Dactylitis: Results from a Multicentre Prospective Observational Study

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).

Novel and reliable DACTylitis glObal Sonographic (DACTOS) score in psoriatic arthritis

OBJECTIVES

Dactylitis is one of the most typical features of psoriatic arthritis (PsA), with a high lifetime prevalence and inclusion in PsA clinical indices. Musculoskeletal ultrasonography (Msk-US) can readily detect inflammatory involvement of finger anatomical structures particular to dactylitis and monitor therapeutic effects. In this study, we aim to identify the characteristic lesions in PsA dactylitis of the hands, assess the reliability of Msk-US in scoring those lesions and develop a DACTylitis glObal Sonographic (DACTOS) score.

METHODS

After a systematic literature review on the use of Msk-US in PsA dactylitis, 12 rheumatologists participated in a three-round Delphi procedure and consensus meeting to agree on the sonographic elementary lesions characterising dactylitis and on the composition of a global sonographic score. Then, a web-based and a patient-based intra-rater and inter-rater reliability exercise was performed to assess those lesions included in the score.

RESULTS

DACTOS score was obtained by summing the scores of each lesion selected in the Delphi survey: subcutaneous soft tissue oedema, flexor tenosynovitis, peritendon extensor inflammation and synovitis. The DACTOS score ranges from 0 to 25. In the reliability exercises, we obtained moderate-to-excellent agreement for the sonographic lesions included in the score.

CONCLUSIONS

The novel DACTOS score is a reliable measure to interpret the multiple characteristic sonographic features of dactylitis. The DACTOS score provides a useful global analysis of dactylitis of the hand and can represent a support to clinical diagnosis as well as a useful tool for the management and research in patients with PsA with dactylitis.

Effectiveness of steroid injection for hand psoriatic dactylitis: results from a multicentre prospective observational study

OBJECTIVE

To assess the effectiveness of steroid injection (local treatment, LT) into the digital flexor tendon sheath of dactylitis in psoriatic arthritis (PsA) patients as compared with systemic treatment (ST).

METHODS

Forty-six PsA patients with a total of 73 dactylitic fingers were assessed in an observational, multicentre, prospective study by the Leeds Dactylitis Index basic (LDI-b) score and evaluated for local pain (visual analogue scale-VAS pain) and functional impairment (VAS-FI). Steroid injection was proposed to all patients. Patients refusing LT were treated with oral NSAIDs. Both the groups continued baseline csDMARDs and/or corticosteroids therapy. The clinical outcomes were measured at baseline, 1 month (T1) and 3 months (T3).

RESULTS

The reduction of VAS-pain, VAS-FI and LDI-b values was statistically significant higher in the LT group (24 patients, 38 dactylitic fingers) as compared with the ST group (22 patients, 35 dactylitic fingers), both at T1 (p < 0.001, p < 0.001 and p = 0.008, respectively) and at T3 (p < 0.001, p < 0.001 and p < 0.001, respectively). A clinically meaningful treatment response (defined as a contemporary reduction of at least 5 points in VAS-pain and VAS-FI or as values of VAS-pain and VAS-FI were both ≤ 2) was observed at T1 in 33 (87%) digits in LT group and in 6 (17%) digits in ST group (p < 0.001). At T3, clinical response improved significantly in both the groups, with significant difference (94% vs 31%, p < 0.001).

CONCLUSIONS

For the first time, we show the effectiveness of steroid injection into the digital flexor tendon sheath in improving clinical aspects of hand psoriatic dactylitis. Key Points • Therapy with steroid injection (local treatment, LT), into the digital flexor tendon sheath for the treatment of active dactylitis in psoriatic arthritis patients, is more effective when compared with systemic treatment (ST) alone. • The reduction of VAS-pain, VAS-functional impairment (VAS-FI) and Leeds Dactylitis Index basic values was statistically significant higher in the LT group as compared with the ST group, both at T1and at T3. • A clinically meaningful response was observed at T1 in 87% of digits of patients treated with steroid injection and in 17% of digits of the systemic treatment group (p < 0.001). At T3, clinical response improved significantly in both the groups, with significant difference. • For the first time, findings from this study show that the use of steroid injections into the digital flexor tendon sheath for psoriatic dactylitis could be an effective and safe first-line therapy for psoriatic dactylitis.

Metabolic Syndrome and psoriatic arthritis: considerations for the clinician

Introduction: Metabolic Syndrome (MetS) is strictly interconnected with systemic inflammation, and increased evidence has described a close link between this condition and Psoriatic Arthritis (PsA).Areas covered: This review summarizes main studies exploring clinical aspects and prevalence of MetS in PsA cohorts. Further, there is accumulating evidence showing shared inflammatory pathways between MetS, its components, and PsA.Expert opinion: The high prevalence of MetS in PsA highlights the need for screening, evaluation, and close monitoring of MetS and its components (namely, diabetes mellitus, obesity, hypertension, and dyslipidemia) in psoriatic patients.Further studies should focus on the pathogenetic link between MetS and PsA. More studies are required to identify appropriate algorithms for the assessment and management of MetS in PsA patients.

Targeted synthetic pharmacotherapy for psoriatic arthritis: state of the art

INTRODUCTION

In recent years, different studies regarding psoriatic arthritis (PsA) have shown the pathogenetic role of dysfunction of signaling pathways involving the phosphodiesterase-4 enzyme and transcription factors or enzymes belonging to the kinase (JAK)-signal family pathway. These also represent the target of several drugs known as targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs).

AREAS COVERED

The authors performed a systematic literature search using the PubMed database, as well as through retrieving data from randomized controlled trials, their post-hoc analysis, and pooled data analysis on the efficacy and safety profile of the PDE4 inhibitor (PDE4i), apremilast, and the inhibitors of JAK (JAKis), tofacitinib, filgotinib, baricitinib, and upadacitinib, in PsA.

EXPERT OPINION

In PsA, the PDE4i, apremilast, and the JAKi, tofacitinib, are effective across multiple clinical domains and have an acceptable tolerability profile, thus expanding the treatment options available for PsA patients. Apremilast and tofacitinib show several advantages mainly represented by their oral administration, a fast onset of action, and a short half-life. Data on tsDMARDs in PsA are still limited, and randomized trials and real-life studies are advocated.

Dactylitis: A pictorial review of key symptoms

Dactylitis refers to a global swelling of a finger or a toe giving it a clinical sausage-shape presentation. It is an extremely suggestive symptom as it guides the rheumatologist towards a shortlist of diagnoses. However, radiologists are less familiar with dactylitis. The aim of this review is to detail and illustrate the main causes of dactylitis using standard X-ray imaging, ultrasound, computed tomography and magnetic resonance imaging in order to make radiologists more familiar with this symptom by illustrating the various conditions that are associated with dactylitis including infection, peripheral spondyloarthritis, sarcoidosis, microcrystalline deposition, osteoid osteoma, and sickle cell disease.

Predominant ultrasonographic extracapsular changes in symptomatic psoriatic dactylitis: results from a multicenter cross-sectional study comparing symptomatic and asymptomatic hand dactylitis

OBJECTIVE

Despite diffuse digital swelling, dactylitis may sometimes be asymptomatic. The objective of this study was to compare the clinical and ultrasonographic features of symptomatic with asymptomatic psoriatic arthritis (PsA) dactylitis.

METHODS

One hundred and twenty-five hand dactylitis were evaluated in a multicenter cross-sectional study for the presence of pain, subjective functional limitation, and tenderness (4-points scale) with the calculation of a Leeds Dactylitis Index (LDI) score. Fingers were subsequently investigated using high-frequency ultrasound (US) both in gray-scale (GS) and power Doppler (PD), for the presence and grading of flexor tenosynovitis, soft tissue edema, subcutaneous PD signal (PDUS), extensor tendon involvement, and joints synovitis. Clinical and US characteristics of symptomatic dactylitic fingers were compared with the asymptomatic dactylitic ones.

RESULTS

Symptomatic fingers (n = 80) had a significantly lower dactylitis duration compared to asymptomatic fingers (n = 36) (p < 0.001). Values of LDI, patient VAS-pain, and VAS-functional score were significantly higher in fingers with symptomatic dactylitis (p < 0.001 and p = 0.010, respectively). Symptomatic dactylitis had a higher prevalence of flexor tenosynovitis of grade > 2, soft tissue edema and subcutaneous PDUS signal (p < 0.001). Asymptomatic dactylitis showed a greater prevalence of joint synovitis (both in GS and in PD) than symptomatic dactylitis (p < 0.001).

CONCLUSIONS

Digital tenderness and pain are linked to US tenosynovitis of grade > 2 and extra synovial abnormalities and conversely asymptomatic dactylitis is associated with joint-based synovitis.Key Points• Digital tenderness and local pain in psoriatic arthritis dactylitis are strongly associated with flexor tenosynovitis of grade> 2, soft tissue edema, and subcutaneous PD signal.• In psoriatic arthritis, asymptomatic dactylitis showed a greater prevalence of joint synovitis than symptomatic dactylitis.• In psoriatic arthritis, ultrasound inflammatory abnormalities are present in about 70% of cold dactylitis which is linked for disease chronicity.• In psoriatic arthritis, the flexor tendon and adjacent soft tissues play a significant role in symptomatic dactylitis.

Ultrasonographic Evidence of Predominance of Acute Extracapsular and Chronic Intrasynovial Patterns in 100 Cases of Psoriatic Hand Dactylitis

OBJECTIVE

To use ultrasonography to study whether the duration of psoriatic dactylitis was associated with different patterns of extracapsular and synovial-based involvement.

METHODS

One hundred cases of hand dactylitis from 85 patients with psoriatic arthritis (PsA) were consecutively enrolled in a multicenter cross-sectional study and divided into 2 groups according to dactylitis duration (shorter or longer than the median: 20 weeks). All dactylitis fingers were investigated using high-frequency ultrasound both in greyscale (GS) and power Doppler (PD), evaluating the presence of flexor tenosynovitis, soft tissue edema, subcutaneous PD signal (PDS), extensor tendon involvement, and joint synovitis.

RESULTS

Cases with a shorter dactylitis duration (< 20 weeks) had a significantly higher prevalence of GS flexor tenosynovitis of grade > 2, PD flexor tenosynovitis, soft tissue edema, and subcutaneous PDS (p = 0.001, p < 0.001, p < 0.05, and p = 0.001, respectively). However, the presence of synovitis in GS and PD mode (in both cases at proximal interphalangeal level) was more frequent in patients with longer dactylitis duration (p < 0.001). When detected in the chronic form, flexor tenosynovitis was grade 2 or lower.

CONCLUSION

In a large cohort of PsA hand dactylitis, we found a predominant extracapsular inflammation (flexor tenosynovitis and soft tissue edema) in early cases and a high prevalence of joint synovitis at proximal interphalangeal level in the chronic form. However, longitudinal imaging studies are needed to clarify these aspects.