A study conducted at the University of Toronto, Canada, examined the clinical predictors for psoriatic arthritis in patients with psoriasis in a cohort of 244 patients who presented with psoriasis without psoriatic arthritis. Serum and DNA samples at baseline were collected and then patients were followed up yearly or sooner if they exhibited symptoms of inflammatory articular disease. When compared with data from patients with psoriatic arthritis who presented a history of psoriasis, the study sample showed lower reported family history of psoriatic arthritis (2.5 vs. 11%, p < 0.01), lower prevalence of nail dystrophy (50 vs. 87%, p < 0.01) and a lower proportion was treated with systemic therapies (19 ...