A series of points to consider to help define the clinical and imaging features of people with psoriasis who transition to psoriatic arthritis (PsA) have been developed by the European Alliance of Associations for Rheumatology (EULAR) in order to identify those who might benefit from a therapeutic intervention.
The fact that psoriasis typically develops some 10 years before PsA, provides an opportunity for clinicians to investigate risk factors and predictors for PsA in those with the skin disease. Now, with the help of both dermatologists and rheumatologists, a EULAR multidisciplinary taskforce of 30 members and from 13 European countries has produced five overarching principles and a total of 10 points to consider.
Published in the Annals of the Rheumatic Diseases, these principles acknowledge that not everyone with psoriasis will go on to develop PsA, and even among those who do develop the arthritis, this can occur at different times. The taskforce also stress the importance of being able to identify specific risk factors for PsA and how these could influence the choice of treatment, which is crucial given that some systemic psoriasis treatments might reduce the risk of transitioning to PsA.
Psoriatic arthritis definitions
The 10 points highlight that arthralgia, together with abnormalities seen on ultrasound or magnetic resonance imaging scans, represent key elements of subclinical PsA that could serve as short-term predictors. Additionally, the more traditional risk factors for PsA – such as psoriasis severity, obesity and nail involvement – can be seen as more long-term disease predictors.
EULAR suggests standard naming to define the three distinct stages relevant to the prevention of PsA: people with psoriasis at higher risk of PsA, subclinical PsA and clinical PsA. This, the EULAR group felt, was important because in other inflammatory rheumatic musculoskeletal diseases, such as rheumatoid arthritis, the clinical onset is usually preceded by a preclinical phase encompassing arthralgia and immunological or imaging abnormalities, but without a clinical diagnosis.
A definition for early psoriatic arthritis was proposed by EULAR based on the development of joint swelling as a clinical outcome measure for trials of PsA prevention.
EULAR believes that the points to consider will help to define the clinical and imaging features of those with psoriasis that raise the index of suspicion for progression to PsA. Furthermore, these points could be used to identify people who could benefit from a therapeutic intervention to delay or prevent PsA.
An additional and important practice issue, is that clinicians inform patients with psoriasis about the risk of developing PsA and encourage them to report any joint-related symptoms to facilitate early diagnosis. Previous studies have shown that even a diagnostic delay as short as six months can lead to significantly more severe radiographic joint damage, worse physical function and decrease the changes of therapeutic success
