Ankylosing Spondylitis vs. Scoliosis: What Are the Differences?

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Ankylosing spondylitis (AS) and scoliosis are both conditions that affect the spine. However, they have some key differences. Scoliosis only affects the spine, while AS can spread to other joints, possibly affecting vision, skin, and internal organs.

This article discusses the differences between ankylosing spondylitis (AS) and scoliosis, including their symptoms, causes, diagnosis, and treatment.

A young person with long dark hair having her spine looked at by a healthcare provider in an office.

Natalia Gdovskaia / Getty Images

Symptoms

Ankylosing spondylitis is arthritis that most often affects the spine, causing inflammation in the joints and tissue attaching bone to bone (ligaments). As the disease progresses, it also leads to stiffness. In severe cases, people with AS can become "stuck" in a bent-over posture.

Scoliosis is an abnormal sideways curve that develops in the spine. This condition is most commonly identified in childhood or early teenage years. It affects around 6 to 9 million people in the United States.

The primary symptom of AS is back pain and stiffness. Other AS symptoms include:

  • Pain and stiffness in other joints of the body
  • Difficulty breathing
  • Decreased appetite
  • Weight loss
  • Diarrhea
  • Stomach pain
  • Fatigue
  • Vision changes

Most people with scoliosis do not have pain when they are first diagnosed. The symptoms of scoliosis are primarily structural—meaning they affect the "shape" of the body—and can cause the following:

  • The head is positioned "off center"
  • One shoulder blade is higher than the other
  • A "hump" on one side of the back when bending forward
  • Uneven sides of the pelvis
  • Arms hang asymmetrically on the sides of the body
  • Ribs protrude on one side
  • The body leans to one side

Causes

Ankylosing spondylitis (AS) is an autoimmune disorder in which the body attacks its own joints and soft tissues. The cause of AS is unknown, but there are risk factors that can increase your chances of getting AS.

AS Risk Factors

Around 80% of scoliosis cases happen without a specific cause (idiopathic). Scoliosis can also be part of a birth defect (congenital) or develop as a side effect of another disease that affects the muscles or nervous system.

Diagnosis

Diagnosis of ankylosing spondylitis or scoliosis begins with a physical exam. AS can cause difficulty moving the affected joints, which leads to decreased range of motion. Scoliosis can be detected by looking at the angle of the spine when a person is bent over.

Imaging is an important part of diagnosing both conditions. Imaging tests can include:

  • X-rays: Used to detect and monitor joint damage from AS and assess the severity of the deformity in the spine from scoliosis
  • Computed tomography (CT scan): Provides more detail about bone damage and assesses the spinal canal that runs through the bones of the spine
  • Magnetic resonance imaging (MRI): Uses magnets and radio waves to produce images that can be used to assess soft tissue and nerve damage that can occur with scoliosis or AS

Treatment

The treatment for either ankylosing spondylitis or scoliosis depends on how severe the condition is but can include medications, physical therapy, and in some cases, surgery.

Medications

Ankylosing spondylitis is an inflammatory condition. Medications that decrease inflammation are used for treatment. Medications that can be used for AS include:

Medication is not used to treat scoliosis.

Physical Therapy

People with AS and scoliosis can both benefit from physical therapy treatment, which can include:

Bracing for Scoliosis

Bracing can be a treatment option for scoliosis, but only if the condition is diagnosed when a person is still growing and the curve of their spine measures between 25 and 40 degrees.

For most young people, wearing a brace can help prevent the curve from getting worse—as long as it is worn 16 to 23 hours per day until they're done growing.

Surgery

Surgery can be a treatment option for ankylosing spondylitis or scoliosis—but only if the condition is severe.

Surgery can help stabilize joints in the spine or straighten it out in people with AS. If AS affects other joints, joint replacement surgery might be required.

Surgery is not usually indicated for scoliosis in children unless the curve of the spine is more than 40 degrees and continues to get worse. For adults, a spinal curve of more than 50 degrees, with nerve damage, can indicate that surgery is needed.

Summary

Ankylosing spondylitis (AS) and scoliosis are conditions affecting the spine, eventually leading to deformities. However, AS can spread to other areas of the body. The exact cause of these conditions is not known. Diagnosis of AS and scoliosis is made through a combination of physical examination and imaging.

Treatment for AS typically includes medication to decrease inflammation. Both conditions are treated with physical therapy and surgery in severe cases.

A Word From Verywell

Ankylosing spondylitis and scoliosis can cause spine deformities that can significantly affect your quality of life. Compliance with your treatment is key for managing symptoms and, in some cases, can slow the progression of the disease. Talk to your healthcare provider about additional treatment options, such as physical therapy, to improve your overall function.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Ankylosing Spondylitis.

  2. American Association of Neurological Surgeons. Scoliosis.

  3. Johns Hopkins Medicine. Scoliosis.

  4. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Ankylosing Spondylitis: Fiagnosis, Treatment, and Steps to Take.

By Aubrey Bailey, PT, DPT, CHT
Aubrey Bailey is a physical therapist and professor of anatomy and physiology with over a decade of experience providing in-person and online education for medical personnel and the general public, specializing in the areas of orthopedic injury, neurologic diseases, developmental disorders, and healthy living.