Prevalence of Psoriasis in Polyarthritic Patients and their Relatives

Abstract

The prevalence of psoriasis in a sample of 738 surgical in-patients at the London Hospital was 1.5% It was 1.2 and 2.0% in a sample of 407 patients with sero-positive rheumatoid arthritis. The occasional association of the 2 diseases is probably coincidental. There was no familial aggregation of psoriasis and sero-positive rheumatoid arthritis, indicating that the diseases are unrelaed. Psoriasis was found in 9.6% of samples of 104 patients with sero-negatlve polyarthritis of typically rheumatoid pattern, a rate at least 5 times as high as In the sero-positive and controls. The association of psoriasis and "sero-negative rheumatoidarthritis" cannot be ascribedto chance. There was somefamil-lal aggregation of psoriasis andsero-negativerheumatoidarthritis. One of the factors determining the clinical association of thes e 2 dis eases may be a genetic one. A latent psoriatic genetic factors may be responsible for the persistent 3ero-negativity of a minority of patients with rheumatoid arthritis.