Introduction
Ankylosing spondylitis (AS) is a chronic inflammatory disease in the spondyloarthritis family that mainly targets the spine and the sacroiliac joints where the spine meets the pelvis. Over time, ongoing inflammation can stiffen spinal segments and, in advanced disease, lead to bony fusion and a forward-stooped posture.
Early symptoms often include inflammatory back pain: stiffness and ache in the lower back or buttocks that worsen with rest—especially at night or in the early morning—and ease with movement or exercise. Hips, shoulders, heels (entheses), and the chest wall can also be involved; eye inflammation (uveitis) occurs in a substantial minority.
AS is more often recognised in men, typically beginning in late adolescence or young adulthood, though women are under-diagnosed in some series. The HLA-B27 gene strongly raises susceptibility but is neither required nor sufficient alone for disease.
Modern care combines exercise and physiotherapy with NSAIDs and, when needed, biologic medicines that block inflammatory pathways such as TNF or IL-17. Surgery is reserved for selected severe deformity or joint destruction. This page is general education—rheumatology teams individualise diagnosis and treatment.
Overview
AS is an immune-mediated axial inflammatory arthritis that can also affect peripheral joints and entheses (tendon–bone junctions).
Without treatment, progressive spinal rigidity and posture change can limit chest expansion and daily function; cardiovascular and osteoporosis risks are also elevated in long-standing disease.
Treatment goals are symptom control, preserved mobility, reduced flares, and prevention of structural damage where possible.
- Inflammatory arthritis mainly of spine and sacroiliac joints
- Classic clue: morning stiffness improving with activity
- Strong HLA-B27 association; onset often in young adults
- May involve eyes, heels, hips, and chest wall
- Diagnosis uses clinical criteria plus MRI/X-ray and labs
- Exercise plus NSAIDs/biologics are mainstays; surgery uncommon
What happens in the body
In genetically susceptible people, immune pathways drive inflammation at entheses and in sacroiliac joints. Repeated inflammation can stimulate abnormal bone formation, eventually bridging vertebrae (syndesmophytes) and reducing flexibility.
Systemic inflammation contributes to fatigue and can affect sites beyond the spine. Extra-articular disease such as anterior uveitis reflects shared immune mechanisms rather than simple “wear and tear.”
- Autoimmune/autoinflammatory attack on axial entheses and joints
- HLA-B27-related immune activation in many patients
- New bone formation can fuse spinal segments over years
- Extra-articular inflammation (e.g., uveitis) may accompany axial disease
Signs and symptoms
Symptoms often start gradually and fluctuate. Common patterns include:
- Lower back or buttock pain worse at night or on waking
- Morning stiffness lasting over 30–60 minutes, easing with movement
- Alternating buttock pain suggesting sacroiliitis
- Reduced spinal flexibility and chest expansion over time
- Hip or shoulder joint pain
- Heel pain or Achilles enthesitis
- Chest-wall pain where ribs meet the spine or sternum
- Fatigue during active inflammatory periods
- Eye pain, redness, or light sensitivity from uveitis
- Mild early disease: intermittent inflammatory back pain
- Advanced untreated disease: marked kyphosis, fused spine, limited mobility
Causes and risk factors
Exact triggers are incompletely understood. Risk factors and associations include:
- HLA-B27 positivity (major genetic risk factor, not destiny)
- Family history of spondyloarthritis
- Male sex (higher classic AS recognition rates)
- Onset typically in teens to thirties
- Possible microbiome and environmental immune triggers under study
- Smoking associated with worse outcomes in axial disease
- Not caused by ordinary postural strain alone—though strain can coexist
- Not contagious and not explained by a single lifestyle choice
Diagnosis and evaluation
Diagnosis combines inflammatory back-pain features with imaging and exclusion of mimics:
- History focused on inflammatory vs mechanical back-pain patterns
- Exam of spinal mobility, chest expansion, sacroiliac tenderness, and entheses
- HLA-B27 testing as a supportive—not standalone—marker
- Inflammatory markers (CRP/ESR) which may be raised or sometimes normal
- MRI of sacroiliac joints for early inflammatory change
- X-rays for established structural sacroiliitis or syndesmophytes
- Eye assessment if uveitis symptoms occur
- Differential diagnosis: mechanical back pain, disc disease, other spondyloarthritides, infection
Treatment and management
Care is long-term and team-based. Do not start biologics or high-dose steroids on your own; discuss fertility, infection screening, and vaccines before advanced therapies:
- Daily posture-focused exercise and physiotherapy to maintain flexibility and chest expansion
- NSAIDs (such as naproxen or indomethacin class agents) as first-line symptom control when suitable
- TNF inhibitors (e.g., adalimumab, etanercept, golimumab, infliximab) when NSAIDs fail and criteria are met
- IL-17 inhibitors and other advanced options per rheumatology guidance
- Short steroid courses or injections only in selected situations—not chronic high-dose oral steroids for axial AS
- Treatment of uveitis with ophthalmology-directed care
- Smoking cessation, bone-health measures, and cardiovascular risk management
- Surgery (e.g., hip replacement or rare spinal osteotomy) only for severe structural problems
- Patient education on flare pacing and work ergonomics
- Regular rheumatology follow-up to track disease activity and drug safety
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- AS itself is not fully preventable, but disability risk can be reduced
- Stay active with spine-safe stretching and strengthening every day
- Avoid prolonged immobility; break up sitting time
- Do not smoke; smoking worsens axial disease outcomes
- Treat eye symptoms early to protect vision
- Maintain healthy weight and address sleep and mood, which affect pain coping
- Keep vaccinations updated before/during immunosuppressive therapy as advised
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Progressive spinal fusion and restrictive posture
- Reduced lung expansion and exercise tolerance
- Recurrent uveitis and potential vision threat if untreated
- Osteoporosis and vertebral fracture risk
- Hip joint destruction requiring replacement in some patients
- Cardiovascular comorbidity associated with chronic inflammation
- Chronic pain, fatigue, and work disability without adequate therapy
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Back or buttock pain with prolonged morning stiffness in a young adult
- Night pain that wakes you and improves with walking
- Sudden red, painful, light-sensitive eye
- Rapidly worsening posture or inability to look forward comfortably
- Unexplained fever with severe back pain (exclude infection)
- New neurological weakness, bladder/bowel change after spinal disease—seek emergency care
- Chest pain with breathlessness—evaluate urgently for cardiac or other causes
Living with the condition
Think of AS management as a daily mobility habit plus medicines when prescribed. Morning stretch routines, swimming, and supervised physiotherapy often help more than long bed rest.
Workstation height, supportive chairs, and paced activity reduce flare impact. Discuss family planning and drug safety with your rheumatologist before conception.
Track stiffness, night pain, and eye symptoms; report flares early so therapy can be escalated before irreversible stiffness accumulates.
Frequently asked questions
What is ankylosing spondylitis?
It is a chronic inflammatory disease mainly affecting the spine and sacroiliac joints, causing pain, stiffness, and—in advanced cases—spinal fusion.
Is AS curable?
There is no permanent cure yet, but exercise, NSAIDs, and biologic therapies can control symptoms and help protect function for many people.
Is it genetic?
HLA-B27 and family history raise risk substantially, but not everyone with the gene develops AS, and some patients are HLA-B27 negative.
When are biologics used?
When inflammatory disease remains active despite optimal NSAIDs and physiotherapy, rheumatologists may recommend TNF or IL-17 pathway inhibitors after screening.
Is surgery required?
Most people never need spine surgery. Operations are considered for severe deformity or destroyed peripheral joints such as the hip.
Can symptoms come and go?
Yes—AS often fluctuates with flares and quieter periods. Consistent exercise and adherence to prescribed therapy shorten and soften flares for many patients.
Important caution
This article is general health education in English. It is not personal medical advice, a prescription, or a substitute for clinical assessment.
Decisions about NSAIDs, biologic medicines, imaging, or surgery should follow evaluation by a qualified clinician, ideally with rheumatology input.
If you develop a painful red eye, sudden neurological deficits, or severe unexplained systemic symptoms, seek urgent or emergency care without delay.