Ankylosing spondylitis and rheumatoid arthritis: what to know

Ankylosing spondylitis, also called axial spondyloarthritis, mainly involves the spine and the joints connecting the spine to the pelvis. Rheumatoid arthritis often affects smaller joints on both sides of the body, especially the hands and feet. A clinician uses the overall pattern, examination, blood tests and imaging rather than one symptom to tell them apart.

People with ankylosing spondylitis commonly develop inflammatory back pain and morning stiffness that improves with movement. Hip, shoulder, rib or heel symptoms may also occur. People with rheumatoid arthritis commonly develop pain, swelling and stiffness in peripheral joints; the hands, wrists and feet are frequent sites. Either condition can cause fatigue, and both may affect structures beyond the joints.

Blood results do not settle the question by themselves. Rheumatoid factor or anti-CCP antibodies can support rheumatoid arthritis in the right clinical setting, while HLA-B27 can support an axial spondyloarthritis assessment. A result may be positive without confirming a diagnosis or negative when disease is present, so examination and appropriate imaging remain important.

Arrange a medical assessment if stiffness, swelling or back pain keeps returning, lasts after rest, limits movement or interferes with sleep and daily activities. Note which joints are involved, whether symptoms affect both sides, what time of day they are worse, and whether movement helps. Also mention eye pain or redness, psoriasis, bowel symptoms and a family history of inflammatory arthritis.

Treatment is matched to the confirmed condition and the joints involved. It may combine anti-inflammatory medication with targeted physiotherapy and exercise therapy. Rheumatoid arthritis often requires disease-modifying medicine managed by a rheumatologist, while ankylosing spondylitis may require medicines that specifically control axial inflammation. Keep active within tolerable limits, but avoid forcing a hot, markedly swollen joint through strenuous exercise.

Seek urgent medical assessment for a suddenly hot, very swollen joint accompanied by fever or feeling acutely unwell, because joint infection must be excluded. New severe eye pain, marked redness, light sensitivity or blurred vision also needs urgent assessment.

Go to emergency care for new weakness or numbness in both legs, loss of bladder or bowel control, numbness around the groin, or severe spinal pain after an injury. These warning signs require rapid evaluation regardless of which arthritis diagnosis is being considered.

Ask which features point toward axial spondyloarthritis, rheumatoid arthritis or another cause; whether blood tests or imaging are appropriate; how to protect movement while symptoms are active; and which medication effects should prompt contact with the clinic. If you already have one diagnosis but develop a new joint pattern, ask whether it reflects the same condition, a treatment effect or a separate problem.