How Ankylosing Spondylitis Progresses

Medically Reviewed by Michael W. Smith, MD on June 19, 2020

The way ankylosing spondylitis (AS) progresses can be very different for different people. Some never have symptoms beyond back pain and stiffness that come and go. Others may go on to have movement problems, a hunched posture, or eye, digestive, or nerve problems.

Treatment is important no matter what stage of ankylosing spondylitis you're in. Medications can slow the spread of AS. Exercise and physical therapy can help you deal with its effects on your body.

If you work with your doctor, take care of yourself with diet and exercise, and take your medications, serious problems are rare.

Early Ankylosing Spondylitis

AS is a type of arthritis that causes inflammation along your spine. It most often starts in the sacroiliac joints at the base of your backbone.

The pain may start on one side, then move to both sides over weeks or months. It might spread to your buttocks. If you wake up in pain, you usually feel better as you move around.

Unlike back pain from an injury or too much exercise, it won’t go away over time. But you can have symptom-free periods between flare-ups.

As your AS gets worse and your body uses more energy to fight the inflammation, you may feel fatigued.

Treatment for early AS: Work with your rheumatologist on a plan to ease your pain. You'll control the pain and inflammation with nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen.

Exercise is so important for people with AS that it's considered part of your treatment. It:

  • Helps keep AS from getting worse
  • Eases pain and stiffness
  • Helps ensure you can get around well

A combination of aerobic, strength-building, stretching, and balancing exercises is best. Work with a physical therapist (PT) on a safe and effective exercise plan.

An anti-inflammatory diet may also help keep AS from getting worse. Eat lots of:

Avoid highly processed foods made with lots of sugar, white flour, unhealthy fats, and chemical additives.

The Stages of Ankylosing Spondylitis

AS often slowly moves up from the base of your spine to your neck. Imaging tests like MRIs can show how serious it is based on how much of your spine is affected. The changes in your spine can be hard for doctors to spot in the first few years, then become more visible.

If the inflammation from AS gets worse, it may affect other parts of your body besides your spine. It often happens in the entheses, the spots where ligaments and tendons attach to your bones. You might have pain in your:

  • Ribs
  • Shoulders
  • Hips
  • Thighs
  • Heels

You can get other inflammatory conditions, too. About a third of people with AS have eye inflammation at least once, often in the iris. Symptoms include:

If this happens at any time over the course of your AS, get care right away to prevent vision loss.

Up to 70% of people with AS have inflammation in their digestive tract, though many don't notice any symptoms. Up to 10% get an inflammatory bowel disease (IBD) like Crohn’s or ulcerative colitis. About 10% of those with AS get psoriasis.

Treatment as AS progresses: NSAIDs can have side effects, including liver and kidney damage. So be sure to take them exactly as your doctor prescribes. If you don't get relief from them, your doctor might suggest a stronger drug called a biologic.

The first one you'll try is likely to be a tumor necrosis factor inhibitor (TNFi) like:

If TNFis don’t help enough, your doctor may try a biologic called an IL-17 inhibitor, like ixekizumab (Taltz) or secukinumab (Cosentyx).

You might also work with an eye specialist, a gastrointestinal (GI) doctor, or a dermatologist.

Advanced Ankylosing Spondylitis

If you have more advanced AS, your doctor may tell you that your spine has fused. That happens when new bone grows between your vertebrae, joining them together.

The more this happens, the less movement you have in your spine. It happens slowly, but it sometimes leads to complete spinal fusion over time.

Fusion in your spine can put you at a high risk for fractures. It can also make your spine curve forward, leading to a hunched-over posture. Physical therapy can help.

Scarring can also spread to the joints between your spine and ribs. And it can move to the areas where your ribs meet your breastbone. You may find it hard to take deep breaths. A respiratory therapist can show you ways to breathe easier.

When advanced AS scars the nerves at the base of your spine, it can lead to neurological problems. They could include a condition called cauda equina syndrome, which may cause:

If this happens, you'll work with a neurologist to manage the symptoms.

AS does not usually lead to these serious problems. To avoid them, take your medications as prescribed and follow your doctor's instructions. Go to all your checkups, even when you’re not having symptoms.

When to Call Your Doctor

Call your doctor if you notice new or worsening symptoms. In particular, you should call your doctor if you have AS and notice: 

  • Breathing problems
  • Vision problems
  • Pain in your chest
  • Serious pain in your back or joints
  • Unexplained weight loss
  • Noticeable stiffening of spine
WebMD Medical Reference



Cleveland Clinic: “Ankylosing Spondylitis.”

Johns Hopkins Medicine: “Ankylosing Spondylitis.”

Spondylitis Association of America: "Overview of Ankylosing Spondylitis, "Most Common Symptoms," "2019 Axial Spondyloarthritis Treatment Recommendations: A Brief Overview For Patients And Families," "Possible Complications: How Is a Person Affected?" "Changing Your Diet," "Exercise."

StatPearls: "Ankylosing Spondylitis."

Johns Hopkins Arthritis Center: "Ankylosing Spondylitis."

Annals of Rheumatic Diseases: "Staging of patients with ankylosing spondylitis: a preliminary proposal."

Rheumatology: "Progress in our understanding of the pathogenesis of ankylosing spondylitis."

Frontiers in Immunology: "The Early Phases of Ankylosing Spondylitis: Emerging Insights From Clinical and Basic Science."

Advances in Pharmacological and Pharmaceutical Sciences: "Disease-Modifying Effects of Long-Term and Continuous Use of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Spondyloarthritis."

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