Ankylosing spondylitis and axial spondyloarthritis: inflammatory back pain that responds to movement
Could an inflammatory condition be causing your back pain?
The myBackPain assessment specifically identifies the inflammatory back pain pattern — the features that distinguish AxSpA from mechanical causes and point toward the right investigation and treatment. Results in minutes.
What is axial spondyloarthritis?
Axial spondyloarthritis (AxSpA) is a chronic inflammatory condition primarily affecting the spine and sacroiliac joints. It is the most important inflammatory cause of back pain to identify because it requires specific medical management and behaves very differently from mechanical back pain. It is frequently misdiagnosed as mechanical back pain for years before the correct diagnosis is made.
AxSpA is an umbrella term covering both non-radiographic AxSpA (where changes are not yet visible on X-ray) and ankylosing spondylitis (where characteristic changes on X-ray are present, including sacroiliitis and spinal fusion in advanced disease). The distinction matters for diagnosis but the underlying biology and treatment are the same.
The single most reliable distinguishing feature of inflammatory back pain is prolonged morning stiffness lasting more than 30 minutes that gradually eases with movement. Mechanical back pain typically eases within minutes of getting up. If your morning stiffness lasts 30 minutes or more and improves with activity rather than rest, inflammatory causes must be considered.
The inflammatory back pain pattern
Back pain onset before age 45 with gradual insidious onset • Morning stiffness >30 minutes improving with movement • Night pain waking you in the second half of the night • Buttock pain, especially alternating sides • Family history of ankylosing spondylitis, psoriasis, or inflammatory bowel disease • Associated uveitis (eye inflammation), skin psoriasis, or gut symptoms.
What causes AxSpA?
AxSpA is driven by chronic inflammation in the sacroiliac joints and spinal entheses — the points where ligaments and tendons attach to bone. The HLA-B27 gene is present in 85–90% of people with ankylosing spondylitis, making it a strong genetic risk factor, though carrying the gene does not mean you will develop the condition.
Over time, the inflammatory process can lead to new bone formation at the entheses. In advanced ankylosing spondylitis, this can result in fusion of spinal segments — the characteristic “bamboo spine” seen on X-ray. Earlier diagnosis and treatment with anti-inflammatory medication has significantly reduced the frequency of advanced fusion in recent decades.
How is it diagnosed?
- Blood tests: CRP and ESR (markers of inflammation), HLA-B27 (positive in 85–90% of ankylosing spondylitis cases)
- Pelvic X-ray: to assess sacroiliac joints for sacroiliitis
- MRI sacroiliac joints: detects early inflammation before X-ray changes develop — the most sensitive investigation in early disease
- Rheumatology referral: a rheumatologist will perform the formal assessment and classification
Earlier diagnosis means earlier treatment, which reduces inflammation, prevents structural damage, and significantly improves long-term outcomes. The 7–8 year average diagnostic delay in AxSpA is one of the most significant problems in inflammatory back pain care. If you have the inflammatory pattern, pushing for investigation is justified.
What helps?
NSAIDs — first-line medication
Anti-inflammatory medication (ibuprofen, naproxen, or prescription NSAIDs) is the first-line treatment for AxSpA. Unlike in most mechanical back pain, regular rather than as-needed use is often more effective. Significant response to NSAIDs is itself diagnostically suggestive of inflammatory disease.
Exercise — essential, not optional
Regular exercise is one of the most important treatments for AxSpA. Swimming, cycling, and specific spinal mobility exercises maintain flexibility, reduce stiffness, and slow structural progression. The NASS (National Ankylosing Spondylitis Society) provides excellent exercise resources.
Biologic therapy
For patients who do not respond adequately to NSAIDs, biologic medications — TNF inhibitors (adalimumab, etanercept) and IL-17 inhibitors (secukinumab, ixekizumab) — are highly effective. They are prescribed and monitored by rheumatologists. Outcomes with early biologic treatment have transformed the prognosis for AxSpA.
Manual therapy
Osteopathy, physiotherapy, and chiropractic can help maintain spinal mobility, address muscle tension, and support the exercise programme. Manual therapy is a useful complement to medical management but does not address the underlying inflammation — medical treatment must not be deferred in favour of manual therapy alone.
Could your back pain be inflammatory rather than mechanical?
The myBackPain assessment identifies the inflammatory back pain pattern and distinguishes it from mechanical causes — pointing you toward the right investigation and treatment pathway.