Ankylosing spondylitis
Axial spondyloarthritis
Autoimmune conditionAn immune-mediated arthritis that mainly affects the spine and the joints where the spine meets the pelvis, causing back pain and stiffness that improve with movement.
For education only — this guide can't diagnose you. If these signs sound familiar, talk with a healthcare provider. Book a consult
What happens
Inflammation targets the places where tendons and ligaments attach to bone, especially in the spine and pelvis. Over years, some people develop extra bone growth that can stiffen or fuse parts of the spine. It's strongly linked to the HLA-B27 gene and often overlaps with eye inflammation, psoriasis, and inflammatory bowel disease.
Who gets it
It usually starts between the late teens and 40s. It was long thought to mainly affect men, but women are often diagnosed years later because their symptoms are mistaken for ordinary back pain.
Signs worth getting checked
- Low back or buttock pain lasting 3 months or more that started before age 45
- Stiffness that's worse in the morning or after rest and better with exercise
- Waking in the second half of the night with back pain
- Heel or Achilles tendon pain
- Fatigue
- A painful, red eye with light sensitivity
Labs to ask about
- HLA-B27
- CRP and ESR (inflammation markers)
- X-ray or MRI of the sacroiliac joints and spine
Treatments your doctor may discuss
- Anti-inflammatory medicines (NSAIDs)
- Daily stretching, exercise, and physical therapy
- Biologic medicines when NSAIDs aren't enough
Supportive steps to discuss with your provider
- Move every day. Stiffness eases with activity.
- Work on posture and spinal mobility with a physical therapist.
- Stop smoking. It's linked to faster progression.
- Check vitamin D and bone density.
See a doctor promptly if you have
- Sudden eye pain, redness, or light sensitivity: get same-day care
- New leg numbness or weakness, or bladder or bowel changes: go to the emergency room
- Back pain with fever or unexplained weight loss
Related conditions
Ready to find the root cause?
Dr. Lesher is a Naturopathic Doctor who focuses on autoimmune and chronic conditions in women. Since 2020, she's helped hundreds of patients stop managing symptoms and start healing.