What causes ankylosing spondylitis?

The condition is not caused by poor posture, ordinary exercise, or something a person did wrong. It can develop without a known family history, and carrying a related gene does not by itself establish the diagnosis.

The HLA-B27 gene variant is strongly linked with ankylosing spondylitis, but it is neither necessary nor sufficient for the condition. Other genes and immune pathways also contribute. Clinicians therefore interpret genetic testing alongside symptoms, examination, blood tests, and imaging.

Inflammation commonly begins around the sacroiliac joints, where the spine meets the pelvis, and may involve spinal joints and tendon or ligament attachment points. Repeated inflammation can lead to stiffness and structural change over time.

Record where pain occurs, whether it wakes you, how long morning stiffness lasts, and whether movement or rest changes it. Also mention heel pain, swollen joints, psoriasis, persistent bowel symptoms, or episodes of a painful red eye.

A primary-care clinician can assess the pattern and refer to rheumatology when inflammatory back pain is suspected. Staying gently active can reduce stiffness, but exercise alone cannot confirm or exclude the condition. Testing decisions should reflect the whole clinical picture.

Arrange assessment if back or buttock pain persists, is accompanied by prolonged morning stiffness, or repeatedly improves with activity but not rest. Earlier evaluation is also sensible when similar inflammatory disease runs in your family.

Seek urgent help for new loss of bladder or bowel control, numbness around the groin, rapidly worsening leg weakness, or severe pain after a major injury. Obtain same-day eye care for a painful red eye with light sensitivity or blurred vision.

Ask which features suggest inflammatory rather than mechanical back pain, whether HLA-B27 testing would change the assessment, and whether imaging is appropriate. If a relative has the condition, clarify which symptoms should prompt evaluation instead of requesting testing without symptoms.