RT Book, Section A1 Yazdany, Jinoos A1 Manno, Rebecca L. A2 Papadakis, Maxine A. A2 McPhee, Stephen J. A2 Rabow, Michael W. A2 McQuaid, Kenneth R. SR Print(0) ID 1184193436 T1 Seronegative Spondyloarthropathies T2 Current Medical Diagnosis & Treatment 2022 YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264269389 LK accessmedicine.mhmedical.com/content.aspx?aid=1184193436 RD 2023/10/04 AB The seronegative spondyloarthropathies are ankylosing spondylitis, psoriatic arthritis, reactive arthritis, the arthritis associated with inflammatory bowel disease, and undifferentiated spondyloarthropathy. These disorders are noted for male predominance, onset usually before age 40, inflammatory arthritis of the spine and sacroiliac joints, asymmetric oligoarthritis of large peripheral joints, enthesopathy (inflammation of where ligaments, tendons, and joint capsule insert into bone), ocular inflammation, the absence of autoantibodies, and a striking association with HLA-B27 (eTable 20–1). HLA-B27 is positive in up to 90% of patients with ankylosing spondylitis and 75% with reactive arthritis. HLA-B27 also occurs in 50% of the psoriatic and inflammatory bowel disease patients who have sacroiliitis. Patients with only peripheral arthritis in these latter two syndromes do not show an increase in HLA-B27.