What Leads To Signs Of Ankylosing Spondylitis Disease And
Know about ankylosing spondylitis, basics, causes & triggers, risk factors, recognising early signs and symptoms, diagnosis, potential complications, treatment and management of ankylosing spondylitis and more.
Written by Dr. Dhankecha Mayank Dineshbhai
Reviewed by Dr. Rohinipriyanka Pondugula MBBS
Last updated on 9th Sep, 2025
Introduction
Imagine waking up every morning with a stiff, aching back that slowly eases as the day goes on. For many, this is just a sign of getting older, but for others, it could be the first clue of a chronic inflammatory condition called Ankylosing Spondylitis (AS). This autoimmune disease primarily targets the spine and sacroiliac joints, but its reach can extend far beyond, affecting eyes, skin, and internal organs. This article will demystify the complex causes of AS, from genetic predispositions to environmental triggers, and provide a clear guide to the symptoms you should never ignore.
What is Ankylosing Spondylitis? Understanding the Basics
Ankylosing Spondylitis is a type of chronic inflammatory arthritis that falls under the broader umbrella of spondyloarthritis. The name itself provides clues: "ankylosis" means fusion, and "spondylitis" means inflammation of the vertebrae. In essence, AS causes inflammation in the joints and ligaments of the spine, which can lead to severe, chronic pain and discomfort. Over time, this persistent inflammation can prompt the body to form new bone in an attempt to heal, leading to sections of the spine fusing. This fusion results in a loss of flexibility and can cause a forward-stooped posture. However, it's a misconception that AS only affects the spine. It's a systemic disease, meaning it can inflame other areas, including the shoulders, hips, ribs, heels, and even organs.
Consult a Rheumatologist for Personalised Advice
The Root Causes: What Triggers Ankylosing Spondylitis?
The exact cause of Ankylosing Spondylitis remains unknown, but decades of research point to a complex interplay of genetic and environmental factors. It's not caused by an injury or something a person did wrong; it's an autoimmune condition where the body's immune system mistakenly attacks its own healthy tissues, primarily in the entheses—the areas where ligaments and tendons attach to bone.
The Primary Genetic Factor: The HLA-B27 Gene
The strongest known risk factor for developing AS is the presence of the HLA-B27 gene. This gene is not a guarantee of disease but a major predisposing factor. According to the Spondylitis Association of America, over 90% of people with AS who are of Caucasian descent have the HLA-B27 gene, though the prevalence varies among ethnicities. It's important to note that having the gene is common—only a small percentage of people with HLA-B27 (estimated 1-10%) actually develop the disease. This clearly indicates that other factors are required to "turn on" the disease process.
The Role of the Immune System and Autoimmunity
In people predisposed to AS, the immune system becomes dysregulated. The prevailing theory is that the HLA-B27 gene may cause the immune system to confuse harmless substances or the body's own tissues for harmful pathogens. This leads to a cascade of inflammatory cytokines, such as Tumour Necrosis Factor-alpha (TNF-alpha) and Interleukin-17 (IL-17), which drive the chronic inflammation characteristic of AS. This is why biologic drugs that target these specific cytokines have been so effective in treatment.
Environmental Triggers and Gut Health
Genetics load the gun, but environment pulls the trigger. Researchers believe certain environmental factors can initiate the disease in genetically susceptible individuals.
- Gut Microbiome: There is a significant link between AS and inflammatory bowel disease (IBD), like Crohn's disease and ulcerative colitis. Studies suggest that an imbalance in gut bacteria (dysbiosis) may increase intestinal permeability ("leaky gut"), allowing bacteria to cross into the bloodstream and trigger an inflammatory immune response that then targets the spine and joints.
- Infections: Certain bacterial infections, particularly gastrointestinal or genitourinary infections, have been studied as
potential triggers for kick-starting the autoimmune response in AS.
Other Risk Factors
It includes:
- Family History: Having a close relative (parent or sibling) with AS significantly increases your risk.
- Age and Sex: Onset typically occurs in late adolescence or early adulthood (ages 17-45). While it was once thought to
be a predominantly male disease, it is now recognised that women are diagnosed just as often, though their symptoms
can present differently.
Recognising the Early Signs and Symptoms of AS
Early detection of AS is challenging because symptoms often mimic common back pain. However, the pattern of pain is
a key differentiator.
The Hallmark Symptom: Inflammatory Back Pain
The cardinal sign of early AS is inflammatory back pain, which has distinct characteristics:
- Gradual Onset: The pain starts insidiously, often in the late teens/20s.
- Morning Stiffness: Stiffness and pain are most severe in the morning or after long periods of inactivity, typically lasting
more than 30 minutes. - Improves with Activity: Unlike mechanical back pain (from a strain or injury), pain from AS tends to get better with
exercise and movement. - Pain at Rest: The pain often worsens during rest or sleep, sometimes waking the person up in the second half of the
night.
Pain Locations and Types
These include:
- Sacroiliac Joint Pain: Pain is often felt deep in the buttocks, alternating from one side to the other. This inflammation of
the sacroiliac joints is called sacroiliitis. - Enthesitis: Pain and tenderness at sites where ligaments or tendons attach to bone, such as the heels (Achilles tendonitis,
plantar fasciitis), under the heel, or around the knee and chest. - Reduced Spinal Mobility: As the disease progresses, you may find it difficult to bend over or twist your torso.
Beyond the Back: Extra-articular Manifestations
AS is a systemic disease, and its signs can appear in other parts of the body:
- Uveitis (Iritis): This is one of the most common complications outside the joints. It involves sudden eye pain, redness,
sensitivity to light, and blurred vision. This is a medical emergency requiring prompt ophthalmologic care. - Fatigue: A profound and persistent lack of energy is a common complaint, caused by the body's constant inflammatory
activity. - Psoriasis: A skin condition causing red, scaly patches.
- Inflammatory Bowel Disease (IBD): Symptoms like chronic diarrhoea and abdominal pain can occur.
How is Ankylosing Spondylitis Diagnosed?
Diagnosing AS can be a lengthy process, as there is no single definitive test. It involves a combination of:
- Medical History and Physical Exam: A doctor, often a rheumatologist, will ask detailed questions about your pain
pattern and family history and perform a physical exam to check for tenderness and range of motion.
Imaging Tests:
- X-rays can show changes in the sacroiliac joints and spine, but these may not appear until years after the disease starts.
- MRI (Magnetic Resonance Imaging) is much more sensitive and can detect early inflammation and changes in the
sacroiliac joints and spine before damage is visible on an X-ray.
Lab Tests:
- The HLA-B27 blood test is used as part of the diagnostic puzzle.
- Inflammation markers like ESR (Erythrocyte Sedimentation Rate) and CRP (C-reactive Protein) are often elevated during active inflammation but can be normal in some patients.
- If you are experiencing a persistent pattern of inflammatory back pain, it is crucial to consult a specialist. You can book
an online consultation with a rheumatologist from Apollo24|7 to discuss your symptoms and get a preliminary
evaluation.
Potential Complications if Left Untreated
Without proper management, chronic inflammation can lead to severe complications:
- Spinal Fusion: Chronic inflammation can lead to the formation of new bone, causing vertebrae to fuse. This results in a
rigid, inflexible spine (bamboo spine) and can impair mobility. - Kyphosis: A forward curvature of the upper spine, leading to a stooped posture.
- Cardiovascular Involvement: AS can increase the risk of cardiovascular disease, including aortitis (inflammation of the aorta).
- Osteoporosis: Weakening of the bones, making them more prone to fractures.
- Difficulty Breathing: If the disease affects the joints between the ribs and spine, it can restrict lung expansion.
Living with and Managing Ankylosing Spondylitis
While there is no cure for AS, effective treatments can control symptoms, reduce inflammation, and prevent
complications. A multi-faceted approach is best:
- Medication: NSAIDs are first-line for pain and inflammation. For more severe cases, disease-modifying antirheumatic
drugs (DMARDs) or biologic therapies (TNF inhibitors, IL-17 inhibitors) are highly effective. - Physical Therapy: This is non-negotiable. A physiotherapist can design a program of exercises to maintain posture,
flexibility, and range of motion. - Lifestyle Modifications: Regular exercise (like swimming and walking), quitting smoking (which worsens AS), and
maintaining a healthy weight are crucial. Some people find that an anti-inflammatory diet helps manage symptoms. - Surgery: In severe cases with joint damage (like hip replacements) or extreme spinal deformity, surgery may be an
option.
Managing AS often requires monitoring other health metrics. Apollo24|7 offers convenient home collection for tests like CRP and ESR to help track inflammation levels from the comfort of your home.
Conclusion
Ankylosing Spondylitis is a complex disease with roots in our genetics and immune system, activated by environmental factors like gut bacteria. Recognising its unique signs, particularly inflammatory back pain that improves with movement, is the critical first step toward a diagnosis. While living with a chronic condition like AS is undeniably challenging, it is also highly manageable. The key is not to dismiss persistent pain as a simple backache. By seeking expert medical advice early, you can create a proactive management plan that combines medication, physical therapy, and lifestyle changes to halt disease progression, preserve mobility, and lead a full, active life.
Consult a Rheumatologist for Personalised Advice
Consult a Rheumatologist for Personalised Advice
Dr Jagan Babu
Rheumatologist
3 Years • MBBS,MD,DNB,DM Rheumatology
Madurai
Apollo Speciality Hospitals KK Nagar, Madurai
Dr. Ramineni Naga Tejaswini
Rheumatologist
3 Years • MBBS, DNB(Internal Medicine), DrNB ( Clinical Immunology and Rheumatology)
Hyderabad
Apollo Hospitals Jubilee Hills Hyderabad, Hyderabad
Dr Aishwarya G
Rheumatologist
10 Years • MBBS,. MD (General Medicine), DM (Clinical Immunology and Rheumatology)
Chennai
Apollo Speciality Hospitals OMR, Chennai
(25+ Patients)
Dr. Zulkarnain
General Physician
2 Years • MBBS, PGDM, FFM
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dr. Thorana Prakash M
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Consult a Rheumatologist for Personalised Advice
Dr Jagan Babu
Rheumatologist
3 Years • MBBS,MD,DNB,DM Rheumatology
Madurai
Apollo Speciality Hospitals KK Nagar, Madurai
Dr. Ramineni Naga Tejaswini
Rheumatologist
3 Years • MBBS, DNB(Internal Medicine), DrNB ( Clinical Immunology and Rheumatology)
Hyderabad
Apollo Hospitals Jubilee Hills Hyderabad, Hyderabad
Dr Aishwarya G
Rheumatologist
10 Years • MBBS,. MD (General Medicine), DM (Clinical Immunology and Rheumatology)
Chennai
Apollo Speciality Hospitals OMR, Chennai
(25+ Patients)
Dr. Zulkarnain
General Physician
2 Years • MBBS, PGDM, FFM
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Dr. Thorana Prakash M
General Physician
2 Years • MBBS
Bengaluru
PRESTIGE SHANTHINIKETAN - SOCIETY CLINIC, Bengaluru
Frequently Asked Questions
1. Can you develop Ankylosing Spondylitis without the HLA-B27 gene?
Yes, it is possible. While the vast majority of AS patients have the HLA-B27 gene, a small percentage (less than 10%) do not. This is sometimes referred to as HLA-B27-negative Ankylosing Spondylitis. Diagnosis in these cases relies more heavily on imaging and clinical symptoms.
2. What does early-stage Ankylosing Spondylitis feel like?
Early-stage AS often feels like a persistent, dull ache deep in the lower back or buttocks, accompanied by significant morning stiffness that lasts over 30 minutes. The pain is typically worse after rest and improves with physical activity or a warm shower.
3. Is Ankylosing Spondylitis considered a disability?
In its advanced stages, AS can be disabling if it leads to severe spinal fusion, chronic pain, and limited mobility that prevents someone from working. However, with modern treatments, the goal is to prevent the disease from reaching a disabling stage. Many people with well-managed AS live full and active lives.
4. What is the life expectancy of someone with Ankylosing Spondylitis?
Most people with AS have a normal life expectancy. The main concern is managing associated comorbidities, such as an increased risk of cardiovascular disease, which requires regular monitoring and a healthy lifestyle.
5. What is the main difference between AS and regular back pain?
The main difference is the pattern. Mechanical back pain is often caused by injury, worsens with activity, and feels better with rest. Inflammatory back pain from AS has no specific injury cause, feels worse with rest and in the morning, and improves with movement and exercise.