Occurrence of sacroiliitis in patients with seronegative oligoarthritis.

The aim of this study was to investigate sacroiliitis in patients with seronegative oligoarthritis. Thirty consecutive patients with seronegative oligoarthritis and no other signs of spondylarthropathy were included. Sacroiliac (SI) joints were investigated by both radiography and magnetic resonance imaging. HLA B27 antigen was studied and family history was reexamined in 2006. Five patients had sacroiliitis. Additionally, 15 patients had HLA B27 antigen or family history of either psoriasis or ankylosing spondylitis. Our conclusion is that during the first decade of seronegative oligoarthritis, HLA B27 antigen, family history, and especially imaging of SI joints reveal in two thirds of the patients the spondylarthritic nature of their disease.