Summary of key differences in PsA and RA
| Psoriatic arthritis | Rheumatoid arthritis | |
|---|---|---|
| Clinical/anatomical | ▸ DIP joint and axial arthritis ▸ Often asymmetrical ▸ Enthesitis common | ▸ MCP and wrist joints ▸ Predominantly symmetrical |
| Genetic | ▸ HLA Cw6 and B27 ▸ IL23 receptor | ▸ HLA DRB1 |
| Pathogenesis | ▸ Absence of circulating autoantibodies ▸ Distinct vascular pathology ▸ T-lymphocyte predominance ▸ Early expression of vascular growth factors | ▸ Circulating autoantibodies RF/ACPA ▸ T-lymphocyte and B-lymphocyte infiltrate ▸ Late expression of vascular growth factors |
| Response to therapy | ▸ DMARDs, eg, methotrexate ▸ TNF inhibitors ▸ Abatacept ▸ Ustekinumab ▸ Secukinumab | ▸ DMARDs, eg, methotrexate ▸ TNF inhibitors ▸ Abatacept ▸ Rituximab ▸ Tocilizumab |
ACPA, anticitrullinated protein antibodies; DIP, distal interphalangeal; DMARDs, disease modifying anti-rheumatic drugs; HLA, human leucocyte antigen; IL, interleukin; MCP, metacarpophalangeal; RF, rheumatoid factor; TNF, tumour necrosis factor.