Seronegative spondyloarthropathy

• Facts:
  A group of arthropathies that test negative for rheumatoid factor
  All cause fusion of the sacroiliac joints
• Diagnosis:
  1) Ankylosing spondylitis
  2) Psoriatic arthritis
  3) Reactive arthritis
  4) Enteropathic arthritis
• Associated With:
  HLA-B27 ( >90% )