Psoriasis and family history of psoriasis may not affect disease severity of rheumatoid arthritis.

The incidence of psoriasis in patients with rheumatoid arthritis (RA) is higher than in the general population. In addition, psoriasis may negatively affect the severity of rheumatological diseases in patients with autoinflammatory or autoimmune diseases. In this study, we evaluated the effect of psoriasis or a family history of psoriasis on the characteristics of RA. This is a cross-sectional study. We included 737 RA patients who met the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) RA Classification Criteria, but did not meet the CASPAR psoriatic arthritis criteria. Subsequently, we compared disease activity, the need for biologic therapy, the number of conventional synthetic disease-modifying anti-rheumatic drugs taken, the frequency of erosive disease and extra-articular involvement, glucocorticoid doses and the Stanford Health Assessment Questionnaire scores between patients with and without a history of psoriasis, and patients with and without a family history of psoriasis. Thirteen (1.8%) patients had psoriasis, while 58 (7.9%) had a family history of psoriasis in first- or seconddegree relatives. All outcome parameters were found to be similar between the groups. We show that concomitant psoriasis has no effect on the evaluated disease characteristics of RA.