Psoriatic spondylitis or ankylosing spondylitis with psoriasis: same or different?

Area of Science:

• Rheumatology
• Immunology
• Musculoskeletal Diseases

Background:

• The axial domain of psoriatic arthritis (PsA) is the least understood musculoskeletal manifestation.
• Understanding axial PsA (axPsA) is crucial given advancements in targeted therapies for spondyloarthritis (SpA).
• There is a need to differentiate axPsA from ankylosing spondylitis (AS) for better clinical trial evaluation.

Purpose of the Study:

• To review and summarize the current knowledge on the differences between axial PsA (axPsA) and ankylosing spondylitis (AS).
• To highlight the importance of evaluating the axial domain in PsA clinical trials.

Main Methods:

• Literature review of recent observational studies.
• Synthesis of current understanding regarding axPsA and AS.

Main Results:

• Axial PsA (axPsA) is positioned within the SpA spectrum, between peripheral PsA and ankylosing spondylitis (AS).
• Ankylosing spondylitis (AS) exhibits more severe axial disease, while axial PsA (axPsA) shows more severe peripheral disease, with similar overall disease burden.
• Axial PsA (axPsA) expression is influenced by factors including age, disease duration, sex, and HLA-B27 status.

Conclusions:

• Axial PsA (axPsA) requires better definition to advance research on its pathogenesis, impact, and treatment.
• Further research is needed to establish prevalence, clinical features, and treatment strategies for axPsA, differentiating it from other axial SpA.