Ankylosing spondylitis and scoliosis both affect your spine, but they are different conditions.

Scoliosis is an atypical sideways curve in your spine that can lead to back pain. It’s estimated to affect about 2% to 3% of people in the United States. For most people, the cause of their scoliosis isn’t known. Sometimes it can be caused by underlying conditions such as spinal infections or cerebral palsy.

Ankylosing spondylitis is an autoimmune condition that’s usually characterized by pain and stiffness in your lower back. It’s estimated to affect 0.2% to 0.5% of people in the United States.

People with ankylosing spondylitis can also have inflammation in other parts of their spine or joints such as their ribs or shoulders. Some people develop problems with their eyes or internal organs.

Keep reading to learn more about the similarities and differences between ankylosing spondylitis and scoliosis.

Scoliosis symptoms

Scoliosis is characterized by an abnormal curvature of your spine that may cause:

Scoliosis can also lead to back pain from increased pressure on your vertebra. Back pain is more common in adults than children.

In a 2019 study, researchers found evidence that people with scoliosis are at an increased risk of many types of injuries, such as:

Ankylosing spondylitis symptoms

Ankylosing spondylitis primarily causes pain and stiffness in your lower back. It’s a progressive condition that may eventually lead to upper back or neck pain. Symptoms tend to go away or improve between flare-ups.

Ankylosing spondylitis can lead to other symptoms, such as:

Ankylosing spondylitis is an autoimmune condition characterized by chronic inflammation of your vertebrae and other joints. Researchers don’t know why it develops, but almost everybody with the disease has the gene HLA-B27. Most people with this gene never develop ankylosing spondylitis, though.

Doctors and other healthcare professionals don’t know why scoliosis develops in about 80% of people who have it. It’s referred to as idiopathic scoliosis when the cause is unknown. It’s thought genes inherited from your parents may make you more prone to getting it.

Some studies suggest it may be related to genes that play a role in the development of your muscles and extracellular matrix, a network of proteins that support many of your tissues.

The other 20% of scoliosis in people may be caused by factors such as:

Ankylosing spondylitis treatment

Ankylosing spondylitis can usually be managed with a combination of physical activity and medications. Treatment options include:

If less intensive options aren’t effective, a doctor may recommend surgery. The most common surgeries performed in people with ankylosing spondylitis include:

Scoliosis treatment

Treatment options for scoliosis include:

  • observation, or waiting to see if the curvature gets worse
  • bracing to prevent the curve from getting worse
  • surgery

Observation

Mild scoliosis curves tend to stay the same in adults. Curves greater than 50 degrees tend to get worse by about 1 degree per year.

Observation is usually recommended for children with mild curves under 20 degrees. Usually, a doctor will want to check your child’s spine about every 6 months with X-rays.

Bracing

Bracing can help the atypical curve in your spine from getting worse. It’s the only treatment that can potentially slow the progression of scoliosis in children who are still growing.

Surgery

Scoliosis surgery is usually performed during childhood to prevent the condition from progressing during adulthood. Surgery is usually only recommended if the spinal curve is greater than 50 degrees and there are signs of it getting worse.

Ankylosing spondylitis diagnosis

Ankylosing spondylitis can be difficult to diagnose in the early stages because inflammation may not always appear on imaging and symptoms can be similar to other conditions.

Doctors usually confirm the diagnosis with the results of imaging tests such as:

A diagnosis can usually be confirmed if imaging shows inflammation in the joints between your lower spine and pelvis and you have at least one of the following:

  • 3 months of lower back pain that gets better with exercise and doesn’t improve with rest
  • limited movement in your lower back
  • limited ability to expand your chest compared with what’s expected for your age and sex

Scoliosis diagnosis

The diagnostic process for scoliosis usually begins with a physical exam. If a doctor thinks you may have an abnormality in your spine, they’ll likely send you for imagining tests such as:

  • X-rays
  • CT scans
  • MRI

A doctor will give you a diagnosis of scoliosis if imaging reveals a curve in your spine greater than 10 degrees.

Ankylosing spondylitis and scoliosis don’t directly cause each other. More research is needed to understand if they’re linked.

In a 2022 study from Taiwan, researchers found that people with scoliosis were more likely to have ankylosis spondylitis than people in the general population. More research is needed to understand if this holds true in other populations.

It’s been suggested that changes in loading on the spine in people with scoliosis may increase the severity of symptoms in people with inflammatory arthritis, such as ankylosis spondylitis. But, in a 2020 study, researchers found people’s scoliosis in their lower back wasn’t associated with inflammatory or degenerative changes.

Ankylosing spondylitis and scoliosis are two conditions that affect your spine. Ankylosing spondylitis is an autoimmune condition that usually causes inflammation in your lower spine. Scoliosis is an atypical sideways curve in your spine that may lead to back pain.

Imaging such as X-rays plays an important part in the diagnostic process for both conditions. Surgery is sometimes used to treat either condition when more conservative treatment options fail.