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Ankylosing spondylitis

Medically reviewed by Last updated on Mar 23, 2023.

What is ankylosing spondylitis?

Harvard Health Publishing

Ankylosing spondylitis is a form of arthritis that causes inflammation and damage in the sacroiliac joints between the spine and the pelvis. It also can affect other areas of the spine and other joints, such as the knee. Eventually, inflamed spinal joints can become fused, or joined together so they can't move independently. The word spondylitis refers to inflammation of the spine; ankylosis means fusion or the melding of two bones into one.

Ankylosing spondylitis

Ankylosing spondylitis is relatively rare. It affects about 1 in 1,000 people. It may run in families, although its cause is not understood. It most commonly strikes otherwise healthy young men. Men get this condition 10 times more often than women. The disorder most often appears between the ages of 20 and 40, but can develop in children.

Symptoms of ankylosing spondylitis

A person with ankylosing spondylitis commonly will feel pain or stiffness in the lower back. The symptoms are typically worse in the morning or after periods of inactivity and improve with activity or exercise. People who have this disorder may feel worse if they do not exercise regularly. (Back pain from many other causes tends to worsen with exercise.)

Usually, back pain begins in the sacroiliac joint and works its way up the lower spine. Eventually, the disorder can affect the entire spine. People can have pain and tenderness in the thighs, hips and other joints of the torso. Other joints, such as knees and ankles, can be inflamed as well, although it usually affects no more than three or four joints in the arms and legs.

As the spine and its supporting structures stiffen, a person may begin to stoop over. With time, bones of the spine can fuse or grow together, causing an extremely stiff, rigid backbone called a poker spine. This may make it difficult to take a deep breath because the rigid spine and stiff joints between the ribs and breastbone make it difficult for the chest to expand. The pain and rigidity in the lower back can cause problems walking. Almost any movement can become painful.

In some cases, inflammation can also affect the lungs, causing shortness of breath, and inflammation in the eyes may cause reduced vision with red, painful eyes.

Other possible symptoms of ankylosing spondylitis include:  

  • Fatigue  
  • Fever  
  • Loss of appetite  
  • Weight loss

Diagnosing ankylosing spondylitis

Your doctor will ask you about your symptoms. He or she will examine you and may recommend X-rays or other imaging tests, such as a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan, to look for problems in your sacroiliac joints or any other joints that are painful or stiff.

Your doctor also may order a blood test to look for a gene called HLA-B27. This gene is found more commonly in people with ankylosing spondylitis than in other people. However, having the HLA-B27 gene does not mean you have or will develop ankylosing spondylitis; and some people with ankylosing spondylitis do not have this gene.

Your doctor will diagnose the condition based on a combination of symptoms, physical examination, blood tests and imaging tests.

Expected duration of ankylosing spondylitis

In many cases, ankylosing spondylitis is mild and may go undiagnosed for years. However, it is a lifelong problem. 

Preventing ankylosing spondylitis

There is no way to prevent ankylosing spondylitis.

Treating ankylosing spondylitis

The aim of treatment is to reduce joint pain and to prevent, delay or correct any damage or deformities of the spine and other joints.


A number of medications may be effective, including anti-inflammatory drugs (such as ibuprofen), pain relievers (such as acetaminophen), sulfasalazine or methotrexate. Intermittent, short-term corticosteroids can be quite effective, whether injected into a joint or taken in pill form. Newer oral medication options include tofacitinib (Xeljanz) and upddacitinib (Rinvoq).

A number of injectable medications may also be quite effective, including:

Daily management

Treatment usually includes physical therapy and exercise. A physical therapist will develop an exercise routine for you that probably will include range-of-motion and stretching exercises to help the spine remain flexible. Abdominal and back exercises can help you maintain good posture so you may be less likely to stoop.

Swimming is an especially good exercise because it may be easier to move stiff, painful areas in the water. Biking also tends to be a good exercise for people with ankylosing spondylitis. Avoid any activities that could put too much stress on your back. For example, jogging may cause back pain to become worse because jogging puts more pressure on spinal joints.

Hot baths, heat and massage can help to relieve pain. If you can, sleep on your back on a firm mattress and use a small pillow or none at all.

Because ankylosing spondylitis can affect the bones of the rib cage, your lung capacity can become restricted. Breathing exercises can help maintain your lung capacity. If you smoke, quitting should be a priority.

Even with the best treatment, some people will develop a fused spine, but most people can still function. At some point, a back brace or other devices, such a corset, cane or joint splints, may help. If other organs are involved, such as your heart or eye, you may have to see a specialist, and may need additional treatment and monitoring. For example, a person with ankylosing spondylitis may need a pacemaker if his or her heart is affected.


As with other forms of arthritis, surgery may be considered as a last resort when other therapies do not work well enough.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

When to call a professional

Contact a health care professional if you have any symptoms of ankylosing spondylitis, especially:

  • Back pain and stiffness that gets worse gradually over weeks or months
  • Early morning stiffness that improves when you take a warm shower or do light exercise, especially if this symptom lasts for weeks or months


People with ankylosing spondylitis usually go through alternating periods where symptoms improve and worsen. These periods can't always be predicted. With treatment, symptoms usually can be relieved or controlled so that you can lead a normal, productive life. However, even with treatment, you may develop permanent posture and movement problems.

Additional info

Arthritis Foundation

Spondylitis Association of America

Learn more about Ankylosing spondylitis

Treatment options

Care guides

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.