[Extraskeletal manifestations of seronegative spondyloarthropathies].

Spondyloarthropathies constitute a cluster of interrelated and overlapping chronic inflammatory rheumatic diseases of unknown etiology that include ankylosing spondylitis, psoriatic arthritis, reactive arthritis, enteropathic arthritis and undifferentiated spondyloarthritis. These diseases are not associated with rheumatoid factor, they occur in genetically predisposed individuals and show a strong association with HLA-B27. The primary pathologic sites include the entheses, the sacroiliac joints and the axial skeleton with or without some nonarticular structures, such as the skin, eye, aortic valve, heart and kidney.