What Are axSpA and AS?

What Are axSpA and AS?

Spondyloarthritis (SpA) is a name given to a group of closely related rheumatoid conditions that primarily affect the spine and other joints. Spondyloarthritis is sometimes referred to as spondyloarthropathy, as in axial spondyloarthropathy, or spondylitis, as in ankylosing spondylitis (AS). Whenever the term “seronegative” precedes any of these terms, it simply means that certain antibodies commonly associated with rheumatoid arthritis and other rheumatoid conditions are not present or detected in blood tests.

Systemic inflammation is a key feature that helps distinguish SpA from other types of arthritis. Osteoarthritis, for example, is more related to “wear-and-tear.” The SpA family of diseases is divided into categories according to their predominant disease feature(s).

These main similarities can occur with any type of SpA:

  • Inflammation in the pelvis and spine that usually causes inflammatory back pain
  • Pain and/or swelling of any other joint in the body
  • Rapid onset of marked pain and redness in one eye at a time (uveitis or iritis)
  • Psoriasis skin rash
  • Inflammation in the intestine (Crohn disease, ulcerative colitis [UC], undifferentiated colitis)
  • Inflammation along the tendons of the finger or toes (dactylitis or “sausage digits”)
  • Inflammation where tendons and ligaments meet the bone, commonly occurring at the back or bottom of the heel (enthesitis)


Spondylitis Association of America. About spondylitis—overview. www.spondylitis.org/Overview

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