What is ankylosing spondylitis?

Updated: May 15, 2020
  • Author: Jean Deschênes, MD, FRCSC; Chief Editor: Hampton Roy, Sr, MD  more...
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Ankylosing spondylitis is a chronic, progressive inflammatory disorder primarily affecting the axial skeleton. Ankylosing spondylitis is one of the seronegative spondyloarthropathies, a group of multisystem inflammatory diseases that affects the spine, peripheral joints, adjacent soft tissues, and extra-articular structures. Most of these disorders are associated with the human leukocyte antigen B27 (HLA-B27) antigen. [1]

In addition to ankylosing spondylitis, the seronegative spondyloarthropathies include the following:

  • Reactive arthritis (also referred to as Reiter syndrome)

  • Inflammatory bowel disease-associated arthritis

  • Psoriatic arthropathy

  • Juvenile spondyloarthropathy

  • Undifferentiated spondyloarthropathies

Several of these disorders share some clinical features, such as sacroiliitis, spondylitis, asymmetric peripheral arthritis, aortitis, clinically evident or occult bowel lesions, and uveitis. Acute anterior uveitis occurs in as many as 30% of patients at some time during the course of ankylosing spondylitis, particularly in persons with the HLA-B27 allele. Patients with ankylosing spondylitis who have peripheral arthritis also have a higher prevalence of uveitis. [2, 3, 4]

Go to Ankylosing Spondylitis and Undifferentiated Spondyloarthropathy for complete information on this topic.

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