The facts you need to know about axial spondyloarthritis (ax-SpA)
What is ax-SpA?
Ax-SpA is an inflammatory arthritis where the main symptom is back pain.1 Axial refers to the central part of the body (including your spine and pelvis), whereas spondyloarthritis is an inflammatory arthritis that affects the spine and limbs.2
Ax-SpA can be split into two groups: radiographic and non-radiographic.1
- Radiographic axial spondyloarthritis or ankylosing spondylitis (AS) is a type of spondyloarthritis where the changes to the joints or spine are visible on x-rays.
- Non-radiographic axial spondyloarthritis (nr-axSpA) is where the changes are not visible on x-rays, but inflammation is visible on MRI or there are symptoms.
Who does ax-SpA affect?
AS usually develops between the ages of 15 and 40 years. It is approximately three times more common in men than in women.3
Similarly, the symptoms of nr-axSpA often develop in late adolescence or early adulthood, before the age of 40 years.4 Women are more likely to have nr-axSpA and tend to have a longer delay in diagnosis compared to men.2
See how many people have axial spondyloarthritis
AS affects 1–2% of Australians3
.png "people-1-as@2x (1)")
See how many people have axial spondyloarthritis
Nr-axSpA affects around 0.1% of Australians5
.png "people-2-nrx@2x (2)")
What are the symptoms of ax-SpA?
The symptoms of ax-SpA can vary between people. Many people experience pain in the lower back, buttocks or hips as an early symptom. Other parts of the body may also become inflamed resulting in pain, stiffness and swelling.6
What causes ax-SpA?
The cause of ax-SpA is not fully understood, but it does have a strong genetic component and can often be seen to run in families. Certain genes may also increase the likelihood of developing ax-SpA. Environmental factors, such as exposure to certain infections or injury to the affected joints, may also increase your risk of developing ax-SpA.6,7
While more research is needed to understand how environmental factors play a role in the development and severity of ax-SpA, it is important to maintain healthy lifestyle choices while living with this condition.7 Visit the Healthy Living section of this website for more information and tips.
What are flares and what causes them?
Flares or flare-ups are times when you experience an increase in your symptoms.8
Symptoms of a flare may include:8
- Back pain and stiffness
- Fatigue
- Pain in joints other than your back
Triggers for ax-SpA flares are largely unknown. They could be due to active inflammation around the affected areas, tightening of muscles, muscle spasms, new bone growth, inflammatory chemicals released in the body, disrupted sleep, stress, or low mood and anxiety.8
What does remission mean?
Remission refers to a low level of disease activity, with little inflammation and/or impact on your daily physical activities.9 This is the main goal of ax-SpA treatment. Your doctor can determine whether you are in remission if you are no longer showing any of the main signs of active disease.
References: 1.National Axial Spondyloarthritis Society. What is Axial SpA? Available from: nass.co.uk/about-as/what-is-axialspa Accessed: August 2025. 2.Spondylitis Association of America. AxSpA in women. Available from: spondylitis.org/resources-support/educational-materials-resources/spa-in-women/ Accessed August 2025. 3. Arthritis Australia. Taking control of your ankylosing spondylitis. Available from: arthritisaustralia.com.au/wordpress/wp-content/uploads/2020/09/Ankylosing-Spondylitis-WEB-2019.pdf Accessed August 2025. 4. Creaky Joints. Non-Radiographic Axial Spondyloarthritis: What is it, and how is it treated? Available from: creakyjoints.org/education/what-is-non-radiographic-axial-spondyloarthritis/ Accessed August 2025. 5. Arthritis Australia. Non-radiographic Axial Spondyloarthritis. Available from: arthritisaustralia.com.au/types-of-arthritis/non-radiographic-axial-spondyloarthritis/ Accessed August 2025. 6. Arthritis Foundation. Ankylosing Spondylitis & nonradiographic axial spondyloarthritis. Available from: arthritis.org/diseases/ankylosing-spondylitis Accessed August 2025. 7. Creaky Joints. What is axial spondyloarthritis? What to know about this inflammatory back pain. Available from: creakyjoints.org/about-arthritis/axial-spondyloarthritis/axspa-overview/what-is-axial-spondyloarthritis/ Accessed August 2025. 8. National Axial Spondyloarthritis Society. Managing my axial SpA (AS) flares. Available from: nass.co.uk/resource/nass-guide-to-managing-your-flares/ Accessed August 2025. 9. Marzo-Ortega H et al. Rheumatology 2018;57(Suppl 6):vi18–vi22. AC-005092-00. AU-RNQ-250036. August 2025.