Ankylosing spondylitis (AS) is a long-term (chronic) condition in which the spine and other areas of the body become inflamed.

AS tends to first develop in teenagers and young adults. It is also around three times more common in men than in women.

Symptoms of ankylosing spondylitis

The symptoms of AS can vary, but usually involve:

  • back pain and stiffness
  • pain and swelling in other parts of the body – caused by inflammation of the joints (arthritis) and inflammation where a tendon joins a bone (enthesitis)
  • extreme tiredness (fatigue)

These symptoms tend to develop gradually, usually over several months or years, and may come and go over time.

In some people the condition gets better with time, but for others it can get slowly worse.

Read about symptoms of ankylosing spondylitis.

When to seek medical advice

You should see your GP if you have persistent symptoms of AS.

If your GP thinks you may have the condition, they should refer you to a specialist in conditions affecting muscles and joints (rheumatologist) for further tests and any necessary treatment.

Further tests may include blood tests and imaging tests.

Read about diagnosing ankylosing spondylitis.

Causes of ankylosing spondylitis

In AS various areas of the spine and other joints become inflamed. As well as causing pain, stiffness and swelling, this inflammation can damage affected areas of the body over time.

In some cases this can lead to some of the individual bones of the spine joining together (fusing), known as ankylosis.

It's not known what causes the condition, but there's thought to be a link with a particular gene known as HLA-B27.

Read about the causes of ankylosing spondylitis.

Treating ankylosing spondylitis

There's no cure for AS and it's not possible to reverse the damage caused by the condition. However, treatment is available to relieve the symptoms and help prevent or delay its progression.

In most cases treatment involves a combination of:

  • exercises carried out individually or in groups to reduce pain and stiffness
  • physiotherapy – where physical methods, such as massage and manipulation, are used to improve comfort and spinal flexibility
  • medication to help relieve pain and reduce inflammation – such as painkillers, anti-tumour necrosis factor (TNF) medication and other forms of biological therapy

Surgery is sometimes needed to repair significantly damaged joints or correct severe bends in the spine, but this is uncommon.

Read about treating ankylosing spondylitis.

Complications of ankylosing spondylitis

The outlook for AS is highly variable. For some people the condition improves after an initial period of inflammation, whereas for others it can get progressively worse over time.

Around 70-90% of people with AS remain fully independent or minimally disabled in the long term.

However, some people eventually become severely disabled as a result of the bones in their spine fusing in a fixed position and damage to other joints, such as the hips or knees.

With modern treatments, AS doesn't normally affect life expectancy significantly, although the condition is associated with an increased risk of other potentially life-threatening problems.

For example, AS can lead to:

  • weakening of the bones (osteoporosis)
  • spinal fractures
  • cardiovascular disease – a group of conditions affecting the heart and blood vessels
  • chest infections
  • rarely, kidney disease

Read about the complications of ankylosing spondylitis.

Information about you

If you have AS, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the AS register.

Ankylosing spondylitis (AS)

Ankylosing spondylitis is a type of arthritis that affects parts of the spine. In this video, an expert describes the long-term effects of the condition, its most common symptoms and the different treatments available.

Media last reviewed: 12/05/2016

Next review due: 12/05/2018

Page last reviewed: 08/07/2016

Next review due: 08/07/2019