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Ankylosing Spondylitis: Your GoodRx Guide

Comprehensive information for you or a loved one — including treatment options and discounts on popular medications.
Mandy Armitage, MDSophie Vergnaud, MD
Written by Mandy Armitage, MD | Reviewed by Sophie Vergnaud, MD
Updated on October 20, 2021

Ankylosing spondylitis, or AS, is a type of arthritis that primarily affects the spine and the sacroiliac (SI) joints, where the spine meets the pelvis. It can affect other joints and cause inflammation in the areas where tendons attach to bones. In severe cases, it can cause stiffness and loss of motion in the spine, changes in posture, and chronic pain.

AS is an autoimmune condition, meaning it is caused by the body’s own immune system reacting to healthy parts of the body. Unlike other autoimmune diseases, AS affects more men than women. It was previously thought that AS was as much as 9 times more common in men, but recent estimates suggest that ratio is closer to 3 to 1. 

AS is 3 times more likely to affect men than women.

It is estimated that AS affects approximately 0.5% of adults in the U.S. But this may vary depending on location and the population studied. 

Symptoms

The symptoms of AS depend on which areas of the body are affected, which varies from person to person. Also, as with many autoimmune diseases, fatigue (extreme tiredness) is a problem for most people with AS. Symptoms typically come on gradually, rather than suddenly.

Eighty percent of people with AS start to have symptoms before age 30.

Low back pain

Low back pain and stiffness are the most common symptoms of AS. Most people (up to 90%) experience back pain as their first symptom. Low back pain due to AS:

  • Improves with exercise

  • Is worse at night

  • May travel down into the buttocks 

Joint pain

Although the spine is most commonly affected, inflammation from AS can affect other places, either in joints or in the tendons and ligaments near joints. This means AS can cause pain and stiffness in the following areas:

  • Hips

  • Knees

  • Ankles

  • Shoulders 

  • Ribs/chest

Coexisting conditions 

People with AS commonly have other autoimmune disorders, which can affect other parts of the body: 

  • Eyes: One in four people with AS have uveitis, which can cause eye redness, blurry vision, and sensitivity to bright light. 

  • Abdomen: Inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis, occurs in about 7% of people with AS, especially women. This can cause abdominal pain and changes in bowel movements.

  • Skin: Almost 10% of people with AS also have psoriasis.

Most people experience symptoms before age 30. AS is commonly diagnosed around age 35 and usually before age 45. 

Causes

In AS, inflammation in the spine and other joints leads to pain and stiffness in those joints. Like with other autoimmune diseases, the exact cause of that inflammation is unknown. Researchers believe that a complex combination of genetics and environmental factors causes the immune system to react abnormally. But it isn’t clear why the immune system’s response is directed at the spine and other affected joints. 

Risk factors for AS include age, sex, and genetics. These aren’t causes but rather factors that make you more likely to develop AS. 

AS is more common in young male adults, and there is a genetic component in the likelihood of developing it. According to one study, a person’s risk of AS is 8% if they have a first-degree relative with it.

A strong link has been found between AS and a gene called HLA-B27. The HLA-B gene family plays an important role in how the immune system functions. HLA-B27 is also found in people with other inflammatory conditions, but the connection with AS is stronger: Up to 85% of people with AS have HLA-B27. But not everyone with HLA-B27 gets AS.

In the U.S., HLA-B27 is much more common in non-Hispanic white people than in other ethnic groups (7.5% versus 3.5%). In groups with a higher prevalence of HLA-B27, AS is more common.

Having any of the following also increases the likelihood of AS:

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Diagnosis

A specific test for AS does not exist. Because of this, and the fact that back and joint pain are relatively common among adults, it can take years for people with AS to get a diagnosis. 

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Getting a diagnosis often requires a combination of your:

  • Symptoms

  • Medical history

  • Family medical history

  • Physical examination

  • Imaging tests 

  • Bloodwork 

X-rays often show signs of inflammation at the SI joints, or sacroiliitis. But not all people with AS have typical X-ray findings. Some people have what is called a “non-radiographic” version of the disease. Research suggests some people with non-radiographic AS go on to develop signs of sacroiliitis on X-rays over time. So your provider may suggest getting an MRI of your spine and pelvis if they think you could have AS. 

Blood tests that look for inflammation can be helpful when autoimmune diseases are a possibility. These include erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). They alone cannot diagnose or rule out AS, but they can provide extra information. 

Testing for HLA-B27 may also be recommended. It’s not a diagnostic test but a piece of the puzzle that can help to get a diagnosis. Remember: A positive HLA-B27 test does not mean you have AS, and a negative test does not mean you don’t. 

Some or all of these tests can be ordered by your primary care provider, but you may also need to see a rheumatologist to help with diagnosis. This is someone who specializes in diagnosing and treating autoimmune conditions. 

Treatment

People who receive a diagnosis of AS will likely be treated by a rheumatologist. The goals of AS treatment are to:

  • Reduce symptoms

  • Maintain motion in the spine and joints

  • Prevent permanent changes in posture

  • Help people live well and keep their independence

Medications are typically recommended first to help with pain and inflammation (more on this below). 

Exercise is also beneficial — for people with AS, it can reduce symptoms and inflammation. Research suggests that an exercise program guided by a trained physical therapist may be more beneficial than a home program. 

If you are new to either exercise or AS, it’s a good idea to speak with your healthcare provider before starting a new exercise program. Be sure to avoid spinal manipulation in order to avoid injury.

In some cases, AS worsens despite treatment with medication. If AS is severe and negatively affects mobility or quality of life, surgery may be necessary. For example, hip replacement can improve motion and reduce pain related to hip arthritis. Spine surgery is usually reserved for people with severe posture changes. The decision to move forward with surgery should be made carefully and on an individual basis.

Medications

Medications that target inflammation or the immune system are often used to treat AS. Your rheumatologist can walk you through the possible side effects of each and help you decide which treatment is right for you.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are often very effective for treating AS, so they are recommended as first-line treatment. Examples include

Research suggests that all NSAIDs are equally effective. Some people will need daily treatment, whereas others may take medication only when needed.

Biologic medications

Biologic disease-modifying medications target specific molecules or cells in the inflammatory process. If treatment with NSAIDs is insufficient, treatment with a tumor necrosis factor (TNF) inhibitor is recommended. Examples include: 

If a TNF inhibitor does not work well enough, other biologic options include secukinumab (Cosentyx) or ixekizumab (Taltz). 

Common concerns

Can ankylosing spondylitis be cured?

No, there is no cure. However, existing treatments can help relieve symptoms and prevent complications. 

Is ankylosing spondylitis different from arthritis?

“Arthritis” simply means inflammation (“itis”) of joints (“arthro”). Different types of arthritis exist, such as osteoarthritis and rheumatoid arthritis. Ankylosing spondylitis is a type of arthritis. 

What complications can arise from AS?

Changes in the spine due to AS can lead to problems. These include spinal fractures, reduced motion in the spine, and even neurological complications. A condition called cauda equina syndrome can sometimes arise. This is when nerves at the bottom of the spinal cord become compressed, causing numbness, weakness, and bowel and bladder problems. 

Other complications include osteoporosis, increased risk of cardiovascular disease, and amyloidosis (a condition of abnormal protein build-up in the organs).

Is ankylosing spondylitis genetic?

Yes, it is partly genetic. If someone in your family has AS, you are more likely to get it. And if you have the gene HLA-B27, you’re more likely to get AS. But there are other factors — not just genes — that cause AS, which are not completely understood.

References

American College of Rheumatology. (2018). What is a rheumatologist?

American Academy of Ophthalmology. (2021). Uveitis

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Amyloidosis Foundation. (2021). Facts.

Bedaiwi, M., et al. (2015). Fatigue in ankylosing spondylitis and non-radiographic axial spondyloarthritis: Analysis from a longitudinal observation cohort. The Journal of Rheumatology. 

Brown, M. A., et al. (2000). Recurrence risk modelling of the genetic susceptibility to ankylosing spondylitis. Annals of Rheumatic Disease.

Costantino, F., et al. (2017). Radiographic sacroiliitis develops predictably over time in a cohort of familial spondyloarthritis followed longitudinally. Rheumatology.

Dagfinrud, H., et al. (2008). Physiotherapy interventions for ankylosing spondylitis. Cochrane Database of Systematic Reviews. 

Jamalyaria, F., et al. (2017). Ethnicity and disease severity in ankylosing spondylitis a cross-sectional analysis of three ethnic groups. Clinical Rheumatology.

Johns Hopkins Arthritis Center. (2021). Ankylosing spondylitis

Jovaní, V., et al. (2017). Understanding how the diagnostic delay of spondyloarthritis differs between women and men: A systematic review and metaanalysis. The Journal of Rheumatology. 

Kroon, F. P. B., et al. (2015). Non-steroidal anti-inflammatory drugs (NSAIDs) for axial spondyloarthritis (ankylosing spondylitis and non-radiographic axial spondyloarthritis). Cochrane Database of Systematic Reviews.

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Spondylitis Association of America. (2021). Overview of ankylosing spondylitis.

Stolwijk, C., et al. (2015). Prevalence of extra-articular manifestations in patients with ankylosing spondylitis: A systematic review and meta-analysis. Annals of Rheumatic Diseases.

Sveaas, S. H., et al. (2020). High intensity exercise for 3 months reduces disease activity in axial spondyloarthritis (axSpA): A multicentre randomised trial of 100 patients. British Journal of Sports Medicine.

Ward, M. M., et al. (2019). 2019 update of the American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network recommendations for the treatment of ankylosing spondylitis and non-radiographic axial spondyloarthritis. Arthritis & Rheumatology.

Wright, K. A., et al. (2015). Time trends in incidence, clinical features, and cardiovascular disease in ankylosing spondylitis over three decades: A population-based study. Arthritis Care & Research.

Zhu, W., et al. (2019). Ankylosing spondylitis: Etiology, pathogenesis, and treatments. Bone Research.

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