The transition from psoriasis to psoriatic arthritis and the early diagnosis of psoriatic arthritis is of considerable scientific and clinical interest. People typically have psoriatic skin disease for a decade or more before they begin to experience the joint involvement of psoriatic arthritis, as well as shed more light on possible risk factors and predictors.
Understanding more about the natural history and trajectory of this disease will help in the future prevention of the transition from psoriasis to psoriatic arthritis and the early diagnosis of psoriatic arthritis is of considerable scientific and clinical interest.
The new EULAR ( The European Alliance of Associations for Rheumatology) points-to-consider were developed by a multidisciplinary task force of 30 members from 13 European countries, with healthcare professionals from rheumatology and dermatology, as well as methodologists and patient research partners.
The work was completed in line with EULAR standardized operating procedures. All information included in the final paper, published in June 2023 issue of the Annals of the Rheumatic Diseases, was based on two systematic literature reviews plus expert consensus.
Overall, 5 overarching principles and 10 points-to-consider were formulated. The principles acknowledge that people with psoriasis may develop psoriatic arthritis at different times – or not at all – and highlight that there is a need for close collaboration between dermatologists and rheumatologists, although the rheumatologist has a key role in psoriatic arthritis diagnosis and management.
They also stress that being able to identify risk factors for psoriatic arthritis may influence therapy choices in people with psoriasis, especially since certain systemic treatments for psoriasis may reduce the risk of transition to psoriatic arthritis.The points-to-consider highlight arthralgia (joint pain) and abnormalities seen on ultrasound or MRI (magnetic resonance imaging) as key elements of sub-clinical psoriatic arthritis that can potentially be used as short-term predictors of who will go on to develop psoriatic arthritis.
This also makes these elements useful to help design clinical trials looking at psoriatic arthritis interception and prevention. Traditional risk factors for psoriatic arthritis development such as psoriasis severity, obesity and nail involvement may represent more long-term disease predictors. As such, these are felt to be less useful for short-term trials investigating the transition from psoriasis to psoriatic arthritis.
The task force also proposed some standard naming for three distinct stages in psoriatic arthritis development. Firstly, people with psoriasis at higher risk of psoriatic arthritis, then people with sub clinical psoriatic arthritis, and then people with clinical psoriatic arthritis. This is important, as it has been shown in other inflammatory rheumatic musculoskeletal diseases that clinical onset is preceded by a pre-clinical phase where a person has arthralgia and immunological or imaging abnormalities, in the absence of a clinical diagnosis. The task force also proposed a definition for early psoriatic arthritis based on the development of joint swelling as a clinical outcome measure for trials of psoriatic arthritis.
EULAR hopes this publication will help to define the clinical and imaging features of people with psoriasis who should raise clinical suspicion for progression to psoriatic arthritis. They also hope it can be used to identify people who could benefit from a therapeutic intervention to delay or prevent psoriatic arthritis.
In the meantime, people with psoriasis should be informed about the risk of developing psoriatic arthritis and encouraged to report their symptoms to facilitate early psoriatic arthritis recognition.