|Etiology and Pathogenesis|
- Psoriatic Arthritis is an immune-medaited arthritis likely triggered in a genetically susceptible individual by an unknown environmental exposure. Whatever the origin the disease is characterized by inflammation of the synovium and the ligamentous insertion points in bones known as the enestheses (enthesitis).
- Psoriatic Arthritis is estimated to complicate 10-30% of cases of psoriasis and typically presents after onset of psoriasis. However, in a minority of patients skin and joint disease can develop concurrently or in some cases arthritis may precede frank psoriasis. The pattern of arthritis is highly variable but is typically polyarticular and often associated with fingernail pitting. Both the small joints of the extremities, especially hands/fingers, can be involved as well as the axial skeleton. The arthritic distribution can be both symmetric or asymmetric.