While the term “ankylosing spondylitis pain” focuses on the discomfort, it represents a broader disease process that involves the immune system, genetics (especially the HLA‑B27 gene), and environmental triggers. Understanding the origins of the pain helps patients and clinicians choose the most effective treatments.

Common Causes

The pain associated with ankylosing spondylitis can be confused with other conditions that cause back or pelvic discomfort. Below are eight to ten common causes that may mimic or coexist with AS pain:

• Sacroiliitis: Inflammation of the sacroiliac joints, often the first sign of AS.
• Mechanical low‑back strain: Muscle or ligament sprains from heavy lifting or poor posture.
• Degenerative disc disease: Age‑related wear and tear of intervertebral discs.
• Rheumatoid arthritis (RA): An autoimmune disease that can affect the spine, though less commonly than AS.
• Psoriatic arthritis: Inflammation of joints in people with psoriasis, which can involve the spine.
• Inflammatory bowel disease (IBD)–related spondylitis: Crohn’s disease or ulcerative colitis can trigger axial arthritis.
• Reactive arthritis: Joint inflammation triggered by an infection elsewhere in the body (e.g., urinary tract infection).
• Fibromyalgia: A chronic pain syndrome that can coexist with AS, amplifying perceived pain.
• Osteitis condensans ilii: A benign condition causing sclerosis of the iliac bone, often mistaken for sacroiliitis.
• Spinal infection (e.g., discitis, osteomyelitis): Though rare, infections can cause severe back pain and must be ruled out.

Associated Symptoms

Because AS is a systemic inflammatory disease, pain is usually accompanied by other signs and symptoms:

• Morning stiffness lasting >30 minutes that improves with activity.
• Reduced range of motion in the lumbar spine and hips.
• Enthesitis – painful inflammation at tendon or ligament insertions (e.g., at the Achilles tendon or the plantar fascia).
• Peripheral arthritis – swelling and pain in the shoulders, knees, or ankles.
• Fatigue and low‑grade fever.
• Uveitis (inflammation of the eye) in up to 40 % of patients.
• Chest expansion limitation, leading to shortness of breath with deep breaths.
• Weight loss or loss of appetite in advanced disease.

When to See a Doctor

Early recognition of ankylosing spondylitis pain improves outcomes. Seek medical attention if you notice any of the following:

• Back pain that improves with movement but worsens after periods of rest.
• Morning stiffness lasting longer than 30 minutes, especially in people under 45.
• Pain localized to the lower back or buttocks on one side.
• Persistent pain that does not respond to over‑the‑counter NSAIDs after two weeks.
• New onset of eye redness, pain, or blurred vision (possible uveitis).
• Difficulty breathing deeply or performing daily activities due to reduced spinal flexibility.
• Family history of AS, inflammatory bowel disease, or psoriasis.

Diagnosis

Diagnosing ankylosing spondylitis involves a combination of clinical evaluation, laboratory testing, and imaging studies.

Clinical Assessment

• Medical history: Duration and pattern of pain, family history, and presence of extra‑spinal symptoms.
• Physical exam: Tests for spinal flexibility (Schober test), sacroiliac tenderness, and eye examination for uveitis.

Laboratory Tests

• HLA‑B27 testing: Approximately 80–90 % of patients with AS are positive, though a positive result alone does not confirm disease.
• Inflammatory markers: Elevated erythrocyte sedimentation rate (ESR) or C‑reactive protein (CRP) support an inflammatory process.
• Complete blood count (CBC) and metabolic panel to rule out infection or other rheumatologic conditions.

Imaging

• X‑ray: Early disease may appear normal; later stages show sacroiliitis and vertebral squaring.
• MRI: The most sensitive test for early sacroiliac inflammation; can detect bone marrow edema before X‑ray changes.
• CT scan: Provides detailed bone architecture, useful for surgical planning.

According to the Assessment of SpondyloArthritis International Society (ASAS) criteria, a combination of imaging evidence and clinical features (or HLA‑B27 positivity with typical symptoms) is required for a definitive diagnosis.¹

Treatment Options

There is currently no cure for ankylosing spondylitis, but a range of treatments can control pain, reduce inflammation, preserve mobility, and improve quality of life.

Medication

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): First‑line therapy (e.g., ibuprofen, naproxen, celecoxib). They relieve pain and may slow radiographic progression.²
• TNF‑α inhibitors: Biologic agents such as etanercept, adalimumab, and infliximab for patients who do not respond adequately to NSAIDs.
• IL‑17 inhibitors: Secukinumab and ixekizumab are newer biologics effective in reducing disease activity.
• Targeted synthetic DMARDs: Janus kinase (JAK) inhibitors (e.g., upadacitinib) are emerging options for refractory disease.
• Corticosteroids: Short courses may be used for acute flares, but long‑term use is discouraged due to side effects.
• Analgesics: Acetaminophen or low‑dose tramadol can be added for breakthrough pain.

Physical Therapy & Exercise

• Daily stretching and range‑of‑motion exercises to maintain spinal flexibility.
• Strengthening of core and back muscles to support posture.
• Aquatic therapy (swimming, water aerobics) reduces joint stress while providing cardiovascular benefits.
• Postural training and breathing exercises to improve chest expansion.

Home & Lifestyle Measures

• Apply heat (warm packs or hot showers) to alleviate muscular stiffness before activity.
• Cold packs for acute inflammatory flare‑ups.
• Maintain a healthy weight to reduce mechanical stress on the spine.
• Avoid smoking – nicotine accelerates spinal fusion and diminishes the efficacy of biologic therapies.³
• Ergonomic adjustments at work (standing desks, lumbar support) to encourage frequent movement.

Surgical Interventions

When severe spinal deformity or nerve compression occurs, surgical options may be considered:

• Spinal osteotomy: Realigns the spine in cases of marked kyphosis.
• Joint replacement: Hip replacement for secondary hip arthritis.
• Decompression surgery: Relieves pressure on spinal nerves.

Prevention Tips

Because genetics play a major role, complete prevention is not possible. However, several strategies can delay onset or lessen severity:

• Engage in regular, low‑impact aerobic activity (walking, cycling) from a young age.
• Practice daily spinal stretching (cat‑cow, thoracic rotations).
• Early screening for HLA‑B27‑positive individuals with a family history of AS.
• Prompt treatment of inflammatory bowel disease, psoriasis, or uveitis—conditions linked to spondyloarthritis.
• Quit smoking and limit alcohol consumption.
• Maintain adequate vitamin D and calcium intake to support bone health.
• Stay informed: regular rheumatology follow‑up allows early adjustment of therapy before irreversible fusion occurs.

Emergency Warning Signs

References

1. van der Heijde D, et al. “2016 ASAS–EULAR management recommendations for axial spondyloarthritis.” Ann Rheum Dis. 2017;76(6):978‑991. DOI:10.1136/annrheumdis-2016-210163.
2. Rudwaleit M, et al. “Non‑steroidal anti‑inflammatory drugs in ankylosing spondylitis: Long‑term effectiveness and safety.” Arthritis Care Res. 2020;72(5):679‑688.
3. Wang X, et al. “Smoking and disease activity in ankylosing spondylitis: a systematic review.” Rheumatology (Oxford). 2021;60(4):1559‑1570.
4. Mayo Clinic Staff. “Ankylosing spondylitis.” Mayo Clinic. Updated 2023. https://www.mayoclinic.org
5. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). “Ankylosing Spondylitis.” NIH. Accessed May 2024. https://www.niams.nih.gov