Ankylosing spondylitis and scoliosis can both affect the spine. Although they have similarities, they are separate conditions.

Ankylosing spondylitis is a form of arthritis that causes joint inflammation. It primarily affects a person’s spine.

Scoliosis is an unusual curving of the spine. A person can be born with this condition, or it can develop over time.

Read on to learn more about the differences between ankylosing spondylitis and scoliosis, including their causes, symptoms, and treatments.

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While both ankylosing spondylitis and scoliosis can affect the spine, they typically cause different symptoms.

Ankylosing spondylitis

The most common symptoms of ankylosing spondylitis are chronic back pain and stiffness.

It is a progressive condition, which means it can worsen over time. Inflammation can spread to the joints between the vertebrae, which are the bones in a person’s spine.

In severe cases, ankylosing spondylitis can cause the vertebrae to become fused and rigid. As a result, the vertebrae can be prone to fractures.

Ankylosing spondylitis can affect other joints, such as the:

  • knees
  • ankles
  • hips
  • shoulders
  • feet

It can also affect the joints between the ribs and spine. This can make breathing difficult.

Many people with ankylosing spondylitis have flares of mild back pain and stiffness that come and go. Others may have chronic, severe pain and limited flexibility in their spine.

Other symptoms of ankylosing spondylitis include:

  • vision changes and eye pain due to inflammation within the eyes
  • fatigue
  • loss of appetite
  • weight loss
  • skin rashes such as psoriasis
  • abdominal pain
  • loose bowel movements

Symptoms can worsen with inactivity. A person may find that exercise and movement help improve their symptoms.

Learn more about ankylosing spondylitis.

Scoliosis

Scoliosis is a condition that causes a person’s spine to curve sideways. This curve can range from mild to severe.

Scoliosis commonly occurs in children and adolescents. The American Association of Neurological Surgeons notes that symptoms generally develop at ages 10–15 years.

Symptoms of scoliosis can include:

  • uneven shoulders
  • one or both shoulder blades sticking out
  • the head not being centered directly above the pelvis
  • one or both hips being raised or unusually high
  • an uneven rib cage
  • an uneven waist
  • a change in the texture or appearance of the skin covering the spine
  • the entire body leaning to one side
  • back discomfort
  • heart and lung issues
  • paralysis

Learn more about scoliosis.

Ankylosing spondylitis and scoliosis also have different causes.

Ankylosing spondylitis

Experts do not yet know the exact cause of ankylosing spondylitis, but some believe it may develop due to a combination of environmental and genetic causes.

A gene called HLA-B27 may increase a person’s chances of developing ankylosing spondylitis. This gene helps a person’s immune system tell the difference between proteins that the body’s cells produce and ones that invading organisms produce.

However, a person may have the HLA-B27 gene and not develop ankylosing spondylitis. Additionally, a person without the gene can develop the condition.

Other genes that may have an association with the development of ankylosing spondylitis include:

  • ERAP1
  • IL1A
  • IL23R

Scoliosis

The cause of scoliosis can depend on which form of the condition a person has.

Scoliosis has three forms:

  • Idiopathic: Idiopathic scoliosis accounts for around 80% of all cases. A doctor will diagnose idiopathic scoliosis if they cannot find a cause for the condition.
  • Congenital: A person who has congenital scoliosis is born with the condition. It can occur if one or more vertebrae do not form completely or do not separate properly.
  • Neuromuscular: Neuromuscular scoliosis occurs due to health conditions that affect nerves or muscles. It can be a result of muscle weakness or wasting. Conditions that cause neuromuscular scoliosis include cerebral palsy and muscular dystrophy.

Treatments for ankylosing spondylitis involve managing a person’s symptoms, while treatment options for scoliosis involve correcting the curvature of the spine.

Ankylosing spondylitis

There is no cure for ankylosing spondylitis. However, a doctor can use certain treatments to help a person manage their symptoms.

Most people with ankylosing spondylitis take medications for the symptoms. These medications can include:

  • over-the-counter anti-inflammatory medications
  • biologic medications, which interrupt specific immune signals to reduce inflammation
  • Janus kinase (JAK) inhibitors, which help stop inflammation from inside certain cells
  • corticosteroids to reduce pain and inflammation

A doctor may also recommend that a person receive physical therapy to help:

  • reduce pain
  • strengthen neck and back muscles
  • strengthen core and abdominal muscles
  • improve posture
  • improve and maintain flexibility in joints

A doctor may recommend surgery if a person has severe joint damage that affects their daily activities. This surgery may involve joint repairs or replacements.

Scoliosis

The method a doctor uses to treat scoliosis can depend on several factors, such as:

  • whether the person is still growing
  • how severe the curve is
  • the location of the curve
  • how likely the curve is to worsen

Once a doctor has assessed a person’s condition, they may recommend one of the following treatment approaches:

  • Observance: Mild cases of scoliosis may not need treatment. However, if a doctor believes the condition may worsen, they may reexamine a person every few months or years.
  • Bracing: Bracing is effective only in children and adolescents who are still growing. It involves wearing a brace around the torso to help prevent the curve from worsening. The amount of time a person needs to wear a brace can vary, but it may be 16–23 hours per day.
  • Surgery: A doctor may recommend surgery for a person who has a spinal curve of more than 40 degrees that is progressing. Surgery aims to correct the curve and fuse areas of the spine to prevent curving.

Diagnosis for both ankylosing spondylitis and scoliosis typically involves imaging tests such as X-rays.

Ankylosing spondylitis

A doctor may ask a person about their medical history and perform a physical exam when diagnosing ankylosing spondylitis.

They may also order certain imaging tests, such as X-rays or MRI scans. Additionally, a doctor may recommend blood tests to:

  • find out whether a person has the HLA-B27 gene
  • check for inflammatory markers
  • check a person’s blood count

Scoliosis

A doctor may diagnose scoliosis by:

  • asking about a person’s medical history
  • performing a physical examination
  • using imaging tests such as X-rays, CT scans, or MRI scans

The following are some questions people frequently ask about ankylosing spondylitis and scoliosis.

Can ankylosing spondylitis cause scoliosis, and vice versa?

No, ankylosing spondylitis and scoliosis cannot cause each other. However, a 2022 study in Taiwan found that the rate of ankylosing spondylitis was three times higher in people who had scoliosis. More research is necessary to learn more about this association.

What can be mistaken for ankylosing spondylitis?

The following conditions have similar symptoms to ankylosing spondylitis:

  • rheumatoid arthritis
  • chronic back pain
  • fibromyalgia
  • psoriatic arthritis
  • enteropathic arthritis
  • diffuse idiopathic skeletal hyperostosis

Can you live a long, healthy life with scoliosis?

Yes, a person with scoliosis can live a healthy life. If they have a curve that does not need surgery, they can participate in the same activities as someone without the condition.

A person who has had surgery for scoliosis will usually be able to do the same activities as a person without the condition. However, they may need to consult their doctor before trying some activities.

Ankylosing spondylitis and scoliosis are two conditions that can affect a person’s spine. Although they have some similarities, they are separate conditions.

If a person or their child has symptoms of either condition, they should consult a healthcare professional.