Ankylosing spondylitis is the leader of a group of inflammatory rheumatisms commonly called spondyloarthritis including reactive arthritis, psoriatic arthritis, undifferentiated spondylitis, rheumatism associated with enterocolopathies as well as certain juvenile spondylitis. These pathologies are characterized by common clinical and radiological manifestations such as inflammatory low back pain, damage to entheses and peripheral joints, as well as extra-articular manifestations affecting the skin, heart, eyes and lungs.
The ASDAS score (Ankylosing Spondylitis Disease Activity Score) quantifies the activity of ankylosing spondylitis. The activity thresholds used are:
- Score < 1.3: Inactive.
- Score ≥ 1.3 and < 2.1: Moderate.
- Score ≥ 2.1 and < 3.5: Active.
- Score ≥ 3.5: Very active.