Living With Arthritis
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Ankylosing spondylitis symptoms

Ankylosing spondylitis (AS), now often called axial spondyloarthritis, is an inflammatory arthritis that mainly affects the spine and sacroiliac joints. It usually starts before age 45. Unlike ordinary back strain, the pain eases when you move and stiffens when you sit or lie still — a pattern NICE asks GPs to treat as a referral clue, not a gym niggle.

Common symptoms of ankylosing spondylitis

  • Lower back and buttock pain that improves with activity, worsens with rest
  • Morning stiffness lasting more than 30 minutes
  • Pain that wakes you in the second half of the night
  • Reduced spinal flexibility (bending forward, side-bending, rotation)
  • Chest tightness from rib-joint involvement
  • Heel pain, eye inflammation (uveitis), or fatigue in some people

When to see your GP

See your GP if you've had back pain for more than three months that improves with movement and worsens with rest — this is a recognised red flag for inflammatory back pain.

How AS symptoms differ from mechanical back pain

Mechanical back pain usually follows lifting, a long drive or a poor night's sleep and eases with rest. AS pain is the opposite: people feel worse after a Sunday on the sofa and better after a walk or a swim. Buttock pain that swaps sides, alternating sciatica-like aches, and stiffness that needs a hot shower before you can put socks on are typical. Symptoms starting before 45, lasting more than three months, and responding to NSAIDs are the cluster NICE NG65 uses to separate inflammatory back pain from everyday strain.

Eyes, heels and chest — symptoms outside the spine

A sudden painful red eye with light sensitivity is uveitis until proven otherwise and needs same-day ophthalmology, not another week of lubricating drops. Heel and Achilles insertion pain (enthesitis) is common. Rib-joint inflammation can make a deep breath feel tight and is sometimes mistaken for a chest infection. Mentioning these extras at a GP appointment is often what moves the story from 'bad back' to 'please consider axial SpA'.

What your GP can do before rheumatology

Ask for a CRP or ESR, and discuss HLA-B27 if the history is typical — a negative gene test does not rule AS out. MRI of the sacroiliac joints is more useful than a plain lumbar X-ray in early disease, because X-rays can stay normal for years. Keep a two-week note of night waking, morning stiffness length, and what movement does to the pain. That note is more useful than another generic 'back pain' leaflet.

This is general information, not a substitute for personalised medical advice.

Frequently asked questions

What are the first signs of ankylosing spondylitis?

The earliest signs of ankylosing spondylitis often include joint pain, stiffness — particularly in the morning or after rest — and reduced flexibility in the affected area. Symptoms typically develop gradually, so keep a short symptom diary and speak to your GP if pain persists for more than a few weeks.

How is ankylosing spondylitis diagnosed in the UK?

In the UK, GPs diagnose ankylosing spondylitis from your symptoms, a clinical examination, and — where appropriate — blood tests, X-rays, ultrasound or MRI. For inflammatory types, your GP may refer you to UK healthcare rheumatology for specialist review under NICE guidance.

Can as symptoms come and go?

Yes. Many people with as experience flares — periods of worse pain, swelling and stiffness — followed by quieter spells. Tracking your flares helps you and your GP spot triggers and adjust treatment.

When should I see a GP about ankylosing spondylitis symptoms?

Book a GP appointment if joint pain has lasted more than a few weeks, is interfering with sleep or daily life, or is accompanied by swelling, warmth, locking or unexplained fatigue. Early assessment leads to better long-term outcomes.

Is ankylosing spondylitis the same as general arthritis pain?

No — there are over 100 forms of arthritis, and ankylosing spondylitis has its own pattern of symptoms, affected joints and treatment pathway. Getting the right diagnosis matters because the most effective treatments differ between conditions.