Psoriatic arthritis in childhood: A commentary on the controversy

Treatment of non-systemic juvenile idiopathic arthritis

In the past two decades, the treatment of juvenile idiopathic arthritis (JIA) has evolved markedly, owing to the availability of a growing number of novel, potent and relatively safe therapeutic agents and the shift of management strategies towards early achievement of disease remission. However, JIA encompasses a heterogeneous group of diseases that require distinct treatment approaches. Furthermore, some old drugs, such as methotrexate, sulfasalazine and intraarticular glucocorticoids, still maintain an important therapeutic role. In the past 5 years, information on the efficacy and safety of drug therapies for JIA has been further enriched through the accomplishment of several randomized controlled trials of newer biologic and synthetic targeted DMARDs. In addition, a more rational therapeutic approach has been fostered by the promulgation of therapeutic recommendations and guidelines. A multinational collaborative effort has led to the development of the recommendations for the treat-to-target strategy in JIA. There is currently increasing interest in establishing the optimal time and modality for discontinuation of treatment in children with JIA who achieve sustained clinical remission. The aim of this Review is to summarize the current evidence and discuss the therapeutic approaches to the management of non-systemic phenotypes of JIA, including oligoarthritis, polyarthritis, enthesitis-related arthritis and psoriatic arthritis.

The epidemiology of pediatric psoriasis: A nationwide cohort study in Taiwan

Psoriasis can affect individuals of all age groups. While the epidemiology of psoriasis in adults has been extensively studied, there is limited research specifically investigating pediatric cases. This study aimed to investigate the prevalence and incidence of skin psoriasis (PsO) and psoriatic arthritis (PsA) among pediatric patients in Taiwan. A nationwide cohort of 17 535 patients with psoriatic diseases under the age of 18 was enrolled from the National Health Insurance Research Database for the period 2000-2013, including 16 129 PsO patients and 2022 PsA patients. The age- and sex-standardized prevalence and incidence of pediatric PsO and PsA were calculated. The 2007 yearly reports of age- and sex-specific distribution of the general population was adopted as a standard. The results showed that between 2000 and 2013, the prevalence for pediatric PsO increased from 0.03% to 0.07%, and from 0.003% to 0.014% for pediatric PsA. During the same period, the incidence slightly decreased from 19.81 to 17.55 per 100 000 for pediatric PsO but increased from 1.02 to 5.06 per 100 000 for pediatric PsA. Adolescents (12 to <18 years) had higher prevalence and incidence rates of PsO and PsA than children (aged ≤ 12 years), with no sex difference observed in either age group. PsA preceding PsO was more common among children than adolescents (27.07% vs. 13.46%). This study provides important insights into the prevalence and incidence of psoriatic diseases in the pediatric population. Further research is needed to identify risk factors for pediatric psoriasis and to investigate its long-term health outcomes.

Juvenile Psoriatic Arthritis: Myth or Reality? An Unending Debate

Juvenile psoriatic arthritis (JPsA) accounts for 1-7% of all cases of juvenile idiopathic arthritis (JIA) and its definition has been a matter of controversy among pediatric rheumatologists for many years. The traditional attribution of JPsA to the spondyloarthropathy group was challenged in the early 1990s, whereas the recent demonstrations of its heterogenous nature have led to questions about its identification as a distinct category in JIA classification. It has been shown that children with the phenotype of JPsA can be divided in two subgroups, one presenting with the features of early-onset ANA-positive JIA, and another that belongs to the spectrum of spondyloarthropathies. The few studies that have compared the clinical characteristics and genetic determinants of JPsA with those of the other JIA categories have obtained contrasting findings. The debate on the categorization of JPsA as a distinct entity within JIA classification is still ongoing and has prompted the revision of its current classification.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Ultrasonographic Assessment for Tenosynovitis in Juvenile Idiopathic Arthritis with Ankle Involvement: Diagnostic and Therapeutic Significance

Background: The role of musculoskeletal ultrasound in JIA is still controversial, although there is growing evidence on its utility, especially in the diagnosis of tenosynovitis. Methods: We presented a retrospective cross-sectional study of a group of patients with JIA with ankle swelling followed in a Pediatric Rheumatology Service of a tertiary-level pediatric hospital in Northern Italy during the follow-up period between January 1st 2003 and December 31st 2019. Preliminary results have been presented at the EULAR Congress 2021. We enrolled only patients who underwent msk-US, and we identified those with a clinical and sonographic diagnosis of tenosynovitis. For each patient, we collected data on demographics, clinical characteristics, and therapeutic strategies during the follow-up. Results: On December 31st 2019, 56 swollen ankles of 48 patients were assessed with msk-US. Twenty-two ankles showed sonographic signs of joint synovitis, sixteen ankles presented signs of both joint synovitis and tenosynovitis, and fourteen ankles presented sonographic signs of tenosynovitis only. Overall, tenosynovitis was detected on 27 (56%) out of 48 children with at least a swollen ankle. In 13 patients out of 27 with tenosynovitis (48%), there was no joint synovitis of ankle or foot. Twenty-five patients with tenosynovitis (92%) achieved clinical and radiological remission: seven patients achieved remission of tenosynovitis with methotrexate only, and fifteen patients with biological drugs alone or in combination therapy. Conclusions: We observed that more than half of the patients with ankle swelling presented a tenosynovitis, and about 50% of them did not show sonographic signs of an active joint synovitis. Among patients with tenosynovitis, biological therapy alone or in association with DMARDs showed effectiveness in inducing disease remission.

The Diverse and Heterogeneous Clinical Features of Juvenile Psoriatic Arthritis

Juvenile Psoriatic Arthritis (JPsA) is a chronic inflammatory disorder that accounts for 3-10% of all juvenile arthritis. The main objective is to identify the clinical features of psoriatic arthritis in children. This study was open-label, single-center, prospective, observational (1989-2020) cohort clinical study included 85 patients (3-17.0 y/o) who met Vancouver and I/E criteria. The features of skin and articular syndromes in children with JPsA were revealed. In most patients with PSA, the disease began at the age of 6.6 years. In childhood, arthritis is usually preceded by psoriasis. The most common clinical form of psoriasis is plaque psoriasis. At the onset of the disease, symmetric polyarthritis predominates. During the disease, transformation of the joint syndrome with a predominance of rheumatoid arthritis is noted. All observed patients showed pronounced osteoporosis, which is not characteristic of JPsA.

Biological classification of childhood arthritis: roadmap to a molecular nomenclature

Chronic inflammatory arthritis in childhood is heterogeneous in presentation and course. Most forms exhibit clinical and genetic similarity to arthritis of adult onset, although at least one phenotype might be restricted to children. Nevertheless, paediatric and adult rheumatologists have historically addressed disease classification separately, yielding a juvenile idiopathic arthritis (JIA) nomenclature that exhibits no terminological overlap with adult-onset arthritis. Accumulating clinical, genetic and mechanistic data reveal the critical limitations of this strategy, necessitating a new approach to defining biological categories within JIA. In this Review, we provide an overview of the current evidence for biological subgroups of arthritis in children, delineate forms that seem contiguous with adult-onset arthritis, and consider integrative genetic and bioinformatic strategies to identify discrete entities within inflammatory arthritis across all ages.

Recent progress in the treatment of non-systemic juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease affecting the joints and other organs that occurs in 1 in 1,000 children in the United States. Given the various categories of JIA, interpretation of the literature can be difficult. In this review, new developments in understanding non-systemic JIA and its treatment will be covered. Recent advances in the journey toward personalized treatment in JIA will be highlighted, including a review of currently available biologic modifiers. Uveitis and the temporomandibular joint will be discussed as particularly challenging treatment issues. Recent guideline updates and literature-guided treatment decisions will be reviewed.

Treatment of Juvenile Spondyloarthritis: Where We Stand

Juvenile spondyloarthritis is a subset of juvenile idiopathic arthritis (JIA) with onset in late childhood and adolescence and a strong association with human leukocyte antigen (HLA) B-27 positivity and familial aggregation that has the potential for axial involvement, potentially leading to ankylosing spondylitis. Current therapy for severe disease relies heavily on tumor necrosis factor inhibitors (TNFi). Treatment paradigms in children largely consist of extrapolation from studies on adults with spondyloarthritis. Additional therapies studied in adults include non-steroidal anti-inflammatory drugs (NSAIDs), blockade of the interleukin-17 (IL-17) and IL-23 axes, blockade of T-cell stimulation, phosphodiesterase (PDE)-4 inhibition, and Janus-activated kinase (JAK) pathway alteration. IL-17 blockade and IL-23 blockade are guideline approved after TNFi failure (and even as an alternative to TNFi) in adults, depending on concomitant inflammatory bowel and skin disease, with JAK and PDE-4 inhibition options following biologic failure. Neither pediatric nor adult guidelines address IL-6 blockade, T-cell co-stimulation blockade, or combination biologic therapy.