Everything You Need to Know About Axial Spondyloarthritis

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Everything You Need To Know About AxSpAGetty Images

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What is axial spondyloarthritis?

Axial spondyloarthritis (axSpA) is a type of inflammatory arthritis that affects the spinal joints and the joints that connect the bottom of the spine to the hip bones (the sacroiliac joints). Experts used to refer to this condition generally as ankylosing spondylitis, or AS, but it has since been replaced with this newer term to describe the wider spectrum of the disease and its different types.

The inflammation from axSpA causes symptoms such as lower back pain that radiates to the hips and buttocks. Over the long term, it can cause the bones of the spine and hip bones to fuse together, leading to osteoporosis and possibly spinal fracture.

Axial spondyloarthritis is thought to affect up to 1.4 percent of people in the United States, but only up to 0.7 percent will ever be diagnosed with it. What’s more, it usually takes people an average of 14 years to receive an official diagnosis. This is partially because the telltale symptom of axSpA—back pain—affects about 80 percent of people in general. “The majority of the American population has back pain during the course of their lives,” says Christopher Ritchlin, MD, MPH, a rheumatologist at University of Rochester Medical Center, in New York. “Only a very small percentage of that back pain is axial spondyloarthritis.”

Until recently, women were especially underdiagnosed. Doctors used to believe the disease primarily affected men, but newer research suggests that women may be just as likely to develop some forms of axSpA as men are.

What are the types of axial spondyloarthritis?

As mentioned previously, there is a spectrum to this disease and it is best identified in the two forms of axSpA:

Radiographic axSpA (r-axSpA)

As its name suggests, this form of axial spondyloarthritis causes damage that is visible on an X-ray to the spine and sacroiliac joints. (This is what was once referred to as ankylosing spondylitis.) Men are more likely to be diagnosed with r-axSpA than women.

Nonradiographic axSpA (nr-axSpA)

This form of axial spondyloarthritis causes damage to the spine that isn’t detected by an X-ray, but may be visible on an MRI. Women are more likely to be diagnosed with nr-axSpA than men.

“Everyone starts out with non-radiographic axial spondyloarthritis,” says John Reveille, MD, a rheumatologist with UTHealth Houston. That’s because in the early stages of the disease, the damage to the spine is often not yet visible on an X-ray.

For some, the disease will progress—which can cause the bones in the spine to fuse together—and the problems will become more apparent. “It takes an average of 7 to 10 years from the onset of inflammatory back pain until the X-rays turn positive, at which point the person would have radiographic axSpA,” says Dr. Reveille. For others living with non-radiographic axSpA, the condition may never become visible on X-rays.

What causes axial spondyloarthritis?

It’s not exactly clear, but many people with the condition have a gene called HLA-B27. One theory is that when people with this gene are exposed to a trigger—like a particular virus or bacteria—axSpA is activated.

“About 8 percent of the American population is HLA-B27-positive, but 90 percent of patients with radiographic axSpA are HLA-B27 positive,” notes Dr. Ritchlin. Yet while axial spondyloarthritis tends to run in families, not everyone who has HLA-B27 will develop the condition.

What are the symptoms of axial spondyloarthritis?

The first symptom of axSpA is inflammatory back pain, which tends to develop before the age of 45 without any specific reason, such as trauma or injury, and may also spread to the buttocks and hips. It tends to be worse at night or in the early morning, and may lessen after you exercise or move around. Other symptoms include:

Lower back pain

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Pain, swelling, or redness in other areas of the body, including the shoulders, neck, ribs, upper spine, knees, ankles, heels, and toes

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Stiffness, especially in the morning or after other long periods of rest

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Radiating buttock pain from side to side while sleeping

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Appetite loss

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Whereas most back pain typically lasts about a week or so, the pain from axSpA may not subside over time. If you don’t experience relief after a week or two, or if your back discomfort is constant or severe, seek out a doctor.

How is axial spondyloarthritis diagnosed?

If your primary-care doctor suspects you have axSpA, you may be referred to a rheumatologist, a doctor who specializes in arthritis. To diagnose axial spondyloarthritis, your rheumatologist will examine the following:

Medical History

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Your doctor will ask you questions about your symptoms, including about pain severity and when it typically appears, as well as your family’s history of medical conditions such as arthritis.

Physical exam

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Your doctor will perform an exam of your spine, pelvis, and hips in the office, looking for signs of swelling in your joints.

Blood tests

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Your doctor may run a test to look for the HLA-B27 gene, which can help confirm a diagnosis of axial spondyloarthritis. They may also run a separate one to look for C-reactive protein, a common sign of inflammation in the body, which is “frequently, but not always, elevated in people with active spondyloarthritis,” says Dr. Ritchlin.

An X-ray

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Your doctor will do an imaging test of your spine to check for bone problems like erosions and fusions. “An X-ray shows you bony changes that are usually something called sclerosis or erosions—bone that has been eroded away or undergone a repair process,” says Dr. Ritchlin.


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Your doctor may perform a magnetic resonance imaging (MRI) scan of your spine. This test can reveal underlying inflammation in the bone, which may appear before spinal erosions or other bone problems. “MRI actually shows you the core of the bone itself and whether or not there is ongoing inflammation that you cannot visualize on X-rays,” Dr. Ritchlin says. This inflammation in the spine is more consistent with a diagnosis of nr-axSpA.

Despite all the tests that are available, diagnosing a person with axial spondyloarthritis isn’t always easy, says Dr. Ritchlin. “The physical examination is not very revealing, because most patients don’t have swollen peripheral joints [such as the shoulder, knee, and ankle], and an investigation of the back in the office is challenging and oftentimes doesn’t reveal what would be seen, for example, on imaging like X-rays or MRIs,” he says. “A lot depends on [a patient’s] history and imaging findings.”

How is axial spondyloarthritis treated?

Axial spondyloarthritis can be treated with a combination of medication and physical therapy. Rarely, surgery may be needed.


About 50 percent of people can manage the symptoms of axSpA with over-the-counter pain relievers, says Dr. Reveille, whereas the other half, who have more advanced forms of axial spondyloarthritis, may need to take a prescription. Medications that might be prescribed include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs): Medications such as ibuprofen, aspirin, and naproxen—which are available over the counter—can relieve pain and lower inflammation levels.

  • Analgesics: Over-the-counter medications like acetaminophen can help ease the pain from axSpA.

  • Biologics: These medications, administered via injection or infusion, target certain proteins in the body to stop the disease from progressing. The most effective biologics for axSpA are tumor necrosis factor (TNF) inhibitors and interleukin (IL-17) inhibitors. Whereas some people will be able to stop taking biologics after a period of time, most will need to continue taking them for the rest of their life, says Dr. Reveille.

  • Sulfasalazine: A type of disease-modifying antirheumatic drug (DMARD), sulfasalazine is usually used to ease pain in joints other than the back and the pelvis.

  • Steroid injections: Corticosteroids, or steroids, usually aren’t injected into the spine, but they can be injected into the knee or shoulder joints to provide quick relief from swelling and pain. Oral steroids usually aren’t given for axSpA.


Most people with axSpA will never need surgery, but if it results in a severely damaged hip joint, it may need to be replaced.

Lifestyle Changes

The same habits that can keep you healthy can also help you manage axial spondyloarthritis. These include:

Exercising regularly: Warming up your joints with exercise can help prevent stiffness and boost your range of motion. Can’t go for a joint-pounding jog? There’s no evidence to show that more intense forms of exercise, like marathon running, can worsen axSpA, says Dr. Ritchlin, but you can always walk, swim, or do yoga or tai chi.

Seeking out physical therapy: Here you can learn specific stretches and movements that will help strengthen your muscles (especially your core) and preserve your range of motion.

Not smoking: Smoking can worsen your axial spondyloarthritis and increase joint damage, according to the Arthritis Foundation.

Eating an anti-inflammatory diet: Following a Mediterranean diet—rich in healthy omega-3 fats as well as vegetables, fruits, and whole grains—may help lower inflammation levels in people with axial spondyloarthritis and could help improve their symptoms, according to a study in the journal Arthritis Research & Therapy.

What are the potential complications of axial spondyloarthritis?

Over time, axial spondyloarthritis can cause other health problems to occur. These can include:

Eye problems

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Inflammation from axSpA can extend to the eye, where it can cause a condition called uveitis. This can cause pain, dryness, redness, and sensitivity to light.

Stomach upset

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Inflammation in the digestive tract can cause abdominal pain and diarrhea. But these can also be caused by inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease. “About one-third of people who are HLA-B27-positive have inflammatory bowel disease,” says Dr. Reveille. “You rarely see it in people who are HLA-B27-negative.”

Heart issues

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AxSpA increases the risk of heart complications like stroke or heart attack, because the chronic inflammation can resize blood cells, which makes these events more likely.

Can you prevent axial spondyloarthritis?

There’s no way to prevent axial spondyloarthritis, but there are ways to prevent it from getting worse—namely, exercising regularly, quitting smoking, eating a healthy diet, and seeking treatment right away if traditional pain relievers like NSAIDs aren’t sufficient to control your symptoms.

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