Psoriatic arthritis (PsA) is a chronic systemic inflammatory disorder characterized by joint and entheseal inflammation with a prevalence of 0.05% to 0.25% of the population and 6% to 41% of patients with psoriasis. PsA is a highly heterogeneous inflammatory arthritis. In this review, current knowledge is discussed regarding the epidemiology of PsA, including disease manifestations, classification criteria for adult and juvenile PsA, methods for recognizing early PsA, including use of screening tools and knowledge of risk factors for PsA, and medical comorbidities associated with PsA.

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The Epidemiology of Psoriatic Arthritis.

Enthesitis in psoriatic arthritis.

Objective. The Assessment of Spondyloarthritis international Society (ASAS) classification criteria for axial spondyloarthritis (axSpA) have added nonradiographic axSpA (nr-axSpA) to the classic ankylosing spondylitis (AS) as defined by the modified New York criteria. However, some confusion remains about differences between classification and diagnosis of axSpA. Our objective was to analyze differences between classification and diagnostic criteria by discussing each feature of the classification criteria based on real cases. Methods. The clinical features of the ASAS classification criteria were evaluated in relation to their significance for an expert diagnosis of axSpA. Twenty cases referred to our tertiary center outpatient clinic were selected because of an incorrect diagnosis of axSpA: 10 cases in which axSpA had been excluded initially because the classification criteria were not fulfilled, and 10 patients who had been previously diagnosed with axSpA because the classification criteria were fulfilled. Upon reevaluation, the former were diagnosed with axSpA while the latter had other diseases. Results. All items that are part of the classification criteria show some variability related to their relevance for a diagnosis of axSpA. There are clinical features suggestive of axSpA that are not part of the classification criteria. Misinterpretation of imaging procedures contributed to false-positive results. Rarely, other diseases may mimic axSpA. Conclusion. Because the sensitivity and specificity of the axSpA classification criteria have been around 80% in clinical trials, some false-positive and false-negative cases were expected. It is hoped that their detailed description and discussion will help to increase the understanding of diagnosing axSpA in relation to the ASAS classification criteria.

https://www.jrheum.org/content/jrheum/42/1/31.full.pdf

Classification and Diagnosis of Axial Spondyloarthritis — What Is the Clinically Relevant Difference?

To determine the current status of psoriatic arthritis, we conducted a retrospective survey by sending questionnaires. The newly visited psoriatic arthritis patients accounted for 10.5% (95% confidence interval, 7.9-13%) of all newly visited psoriasis patients (n = 2581) between April 2014 and March 2015 in 73 institutes. Additionally, questionnaires on detailed patients' information were returned by 92 institutes (response rate, 70.8%), where 1282 patients with psoriatic arthritis were identified. There was a male predominance. The mean onset age of psoriatic arthritis was 44.9 years, and mean onset age for cutaneous psoriasis (36.4 years) was lower than that for arthritis (45.1 years). The mean duration in patients who developed psoriasis prior to arthritis was 11.2 years, while that in patients preceded by arthritis was 4.4 years. According to the Moll and Wright criteria, polyarthritis type was most common (36%), followed by distal interphalangeal type (26%) and oligoarthritis type (22%). Peripheral joint pain was 61.5%, back pain such as lumbago and neck pain was 34.3%. Enthesitis and dactylitis were observed in 28.3% and 59.2%, respectively. Biologics were used in 55.5% of psoriatic arthritis patients, and 31% used disease-modifying antirheumatic drugs. In conclusion, the ratio of psoriatic arthritis in Japan is increasing, and nearly 10% of new psoriasis patients had psoriatic arthritis. This study shows the current status of psoriatic arthritis in Japan, including several unexpected findings such as male predominance, longer duration between the onset of cutaneous psoriasis and arthritis, and dominance of polyarthritis.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1346-8138.13342

Epidemiological analysis of psoriatic arthritis patients in Japan.

/pdf/langfassung-zur-s3-leitlinie-axiale-spondyloarthritis-1sjfb0k2sm.pdf

Langfassung zur S3-Leitlinie Axiale Spondyloarthritis inklusive Morbus Bechterew und Frühformen, Update 2019

OBJECTIVES Dactylitis is a common but little studied feature of spondylarthritis (SpA). Our objective was to assess the prevalence of dactylitis among a cohort of patients with spondylarthritis in a tertiary care centre and to describe the clinical characteristics of dactylitis. METHODS This was a prospective single centre observational study carried out in 2010. The patients included had been diagnosed as having definite SpA based on Amo's criteria. Each patient was interviewed by a physician. The data collected included prevalence of dactylitis and its clinical characteristics, effectiveness of the different treatments, and association with severe manifestations of SpA, and analysed by descriptive analysis. RESULTS 275 consecutive SpA patients were assessed: mean age 43.2±13.5 years, mean disease duration 14.0±11.8 years, 169 (61.4%) were men. In all, 59 patients (21.5%) suffered from SpA-associated dactylitis. The localisation of dactylitis was toes in 46 patients (78.0%) and/or fingers in 25 patients (42.4%). The most frequent localisations were the second toe and the second finger. Dactylitis was the first symptom of SpA in 14 patients (5.1%), and 28.8% (n=17) of dactylitis appeared within the first 5 years of disease. Dactylitis was present in 35.1% (n=13) of patients with undifferenciated SpA and in 30.6% (n=15) of patients with psoriatic arthritis. It was significantly associated with history of peripheral arthritis or heel pain. In our population, there was no correlation between dactylitis and HLA B27 status or sex and it was not a marker of severity of disease. CONCLUSIONS Dactylitis is a frequent manifestation in SpA (21.5%) particularly in peripheral disease and it may be the first manifestation of the disease with localisation being more frequent in the toes.

Roure F

Papers

Prevalence and clinical characteristics of dactylitis in spondylarthritis: a descriptive analysis of 275 patients.