Ankylosing Spondylitis: What It Is, What It Feels Like, and How It's Treated
An introduction to ankylosing spondylitis (AS) — what it is, who gets it, how it's diagnosed, and what living with it looks like.
Medical Disclaimer
This content is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your doctor or another qualified health professional with any questions you may have regarding your health.
Imagine waking up every morning with a spine so stiff it takes an hour of moving around before you feel like yourself. Imagine being told for years that your back pain is "just posture" or "stress" — while something very real is quietly changing your body. That's the reality for millions of people living with ankylosing spondylitis, a condition so often misunderstood that many people wait nearly a decade before getting a name for what they're experiencing.
This article is your starting point. Whether you've just been diagnosed, you're trying to make sense of your symptoms, or you're supporting someone you love, we'll walk through everything you need to know — in plain English, without the jargon.
What Is Ankylosing Spondylitis?
Ankylosing spondylitis (pronounced ank-ih-LO-sing spon-dih-LY-tis) — often shortened to AS — is a type of chronic inflammatory arthritis that primarily affects the spine and the sacroiliac joints, which are the joints at the base of your spine where it connects to your pelvis.
The name tells you a lot: ankylosing means "fusing" or "stiffening," and spondylitis means "inflammation of the vertebrae" (the bones of your spine). In AS, the immune system mistakenly attacks the areas where tendons and ligaments attach to bone — a process called enthesitis. Over time, this repeated inflammation can cause the body to try to heal itself by growing new bone. In some cases, this can cause vertebrae to gradually fuse together.
AS belongs to a broader family of conditions called spondyloarthritis (SpA) — a group of inflammatory diseases that share some features, including inflammation in the spine and sometimes the skin, eyes, or gut.
Crucially: AS is not the same as ordinary back pain. It is an autoimmune-related condition, and it does not go away with rest. In fact, rest often makes it worse.
Who Gets Ankylosing Spondylitis?
AS affects approximately 1 in 200 people, making it more common than many people realise. It tends to appear in late adolescence or early adulthood — most people develop their first symptoms between the ages of 17 and 35.
Historically, AS was considered a condition that primarily affected men. We now know that's not quite right — AS affects people of all genders, but it often presents differently in women (more peripheral joint involvement, less spinal fusion visible on X-ray), which has contributed to women being diagnosed later or less frequently. Research is still catching up, but awareness is improving.
One significant genetic factor is the HLA-B27 gene. Approximately 90% of people with AS carry this gene variant. However — and this is important — the vast majority of people with HLA-B27 never develop AS at all. Having the gene increases risk but does not mean AS is inevitable.
What Does Ankylosing Spondylitis Feel Like?
The hallmark symptom of AS is chronic inflammatory back pain — but it has a distinctive character that sets it apart from the more common mechanical back pain most people experience from time to time. Inflammatory back pain from AS tends to:
- Start gradually, often in the lower back or buttocks
- Be worse in the morning — many people describe a deep, aching stiffness that makes getting out of bed feel like a significant effort
- Improve with movement and exercise — unlike mechanical back pain, which often gets worse with activity
- Worsen with prolonged rest or inactivity
- Disturb sleep, often waking people in the second half of the night
Beyond back pain, AS can also cause profound fatigue, pain and stiffness in the neck, hips, and shoulders, enthesitis at the heel or foot, peripheral arthritis in the knees, ankles, or wrists, and chest tightness where the ribs meet the spine.
Some people also experience uveitis (inflammation of the eye, affecting around 1 in 3 people with AS), psoriasis, and inflammatory bowel symptoms such as Crohn's disease or ulcerative colitis. The severity of AS varies enormously — there is no single "AS experience."
How Is Ankylosing Spondylitis Diagnosed?
On average, people wait 7 to 10 years from the onset of symptoms to receiving a confirmed diagnosis. AS-related pain is often attributed to muscle strain; early AS may not show on standard X-rays; and symptoms in women and younger people are sometimes dismissed. Diagnosis is made by a rheumatologist and involves:
- Clinical assessment — pain onset, improvement with movement, morning stiffness duration, family history
- Blood tests — HLA-B27, CRP and ESR (note: inflammatory markers can be normal in AS even during active disease)
- Imaging — MRI detects early sacroiliac joint inflammation; X-rays assess later structural changes
If you've been experiencing persistent inflammatory-pattern back pain, especially starting before age 40, it's worth asking your GP for a referral to a rheumatologist.
How Is Ankylosing Spondylitis Treated?
There's no cure for AS yet — but treatment has come a long way, and many people achieve significant relief and live full, active lives. Treatment is guided by a rheumatologist and typically involves medication, exercise, and self-management.
Medication
- NSAIDs (e.g. naproxen, ibuprofen) — first line treatment; reduce inflammation and pain; regular use may help slow disease progression
- Biologics — TNF inhibitors and IL-17 inhibitors target specific immune pathways and have transformed outcomes for many people with AS
- JAK inhibitors — newer oral medications for people who haven't responded to biologics
- Corticosteroid injections — for specific joints or short-term flare management
Exercise — More Important Than You Might Think
In AS, exercise isn't optional — it's a core part of treatment. Regular movement helps maintain flexibility and posture. Recommended approaches include hydrotherapy, stretching and flexibility work, low-impact aerobic exercise (swimming, cycling, walking), and physiotherapy with an AS specialist.
Living With Ankylosing Spondylitis
AS is a lifelong condition, but it doesn't define what your life looks like. Many people with AS work, maintain relationships, pursue passions, and find real joy — with the right support and strategies in place.
- Pacing — spreading activity across the day rather than pushing through, then crashing
- Heat — warm showers or heat pads in the morning to ease stiffness
- Sleep positioning — a firm mattress and sleeping on your back can help maintain spinal alignment
- Tracking symptoms — noticing patterns helps you communicate effectively with your healthcare team
- Building your team — a rheumatologist, physiotherapist, and GP who understand AS make an enormous difference
You are not alone in this. The AS community is active, warm, and deeply knowledgeable. Connecting with others who truly get it — through charities, online communities, or support groups — can be one of the most powerful things you do.
Key Takeaways
- Ankylosing spondylitis (AS) is a chronic inflammatory arthritis that primarily affects the spine and sacroiliac joints
- It is not ordinary back pain — it improves with movement and worsens with rest
- AS affects people of all genders, often starting in late teens to early thirties
- Diagnosis takes an average of 7–10 years — advocating for a rheumatology referral early matters
- Treatment includes NSAIDs, biologics, and — crucially — regular exercise and physiotherapy
- Many people with AS live full, active lives with the right treatment and support