1 in 100

Nearly 1 in 100 Americans have spondyloarthritis, about 1% of the population.


The typical age of onset spondyloarthritis is between 17 and 45.


people in the U.S are estimated to have axial spondyloarthritis.

What is spondyloarthritis?

Spondyloarthritis is an umbrella term for several chronic inflammatory conditions that are characterized by inflammation in the spine (“spondylitis”) and joints (“arthritis”). Researchers are generally unsure about what causes the group of conditions, but know that they are immune-mediated, which means that they all involve inflammation that likely result from an abnormal response from your immune system.

The types of spondyloarthritis include: ankylosing spondylitis, reactive arthritis, psoriatic arthritis, enteropathic arthritis, undifferentiated spondyloarthritis, and juvenile spondyloarthritis.

Who is affected?

Anyone can be diagnosed with spondyloarthritis, and ages of diagnosis vary for each type of the condition. Juvenile spondyloarthritis typically produces symptoms before age 16, while ankylosing spondylitis generally starts between ages 20 and 30. [1] [2]

Researchers are unsure about what causes spondyloarthritis, but the main gene involved in all types is HLA-B27. If you have the gene, you may be more at risk of developing the condition. [3]

About six percent of the general population has this gene, and a blood test helps you determine whether you have it. [4] A positive test result means that you have proteins called antigens on your disease-fighting white blood cells, and that you are more at risk of developing spondyloarthritis. But not everybody with HLA-B27 develops the condition.

What happens in your body?

For many people with spondyloarthritis, the first and primary symptom is pain in the lower back and hips, especially after inactivity and in the morning. Pain can occur in other areas as well, and can range from mild to severe.

Common symptoms of spondyloarthritis include: [5] [6] [7]

Ankylosing spondylitis

  • Lower back and buttock pain and stiffnes
  • Pain or swelling in the heel or foot
  • Pain in your ribcage, such as when you exhal
  • Reactive arthritis
    • Joint pain and stiffness in knees, ankles, and feet
    • Eye inflammation

Psoriatic arthritis

  • Stiffness, pain, and tenderness in one or more joints
  • Swollen fingers and toes, which can resemble sausages

Enteropathic arthritis

  • Stiff, sore back
  • Full body aches
  • Abdominal pain
  • Diarrhea

Undifferentiated spondyloarthritis

  • Back pain
  • General stiffness of the body
  • A history of swelling in the feet and hands

Juvenile spondyloarthritis

  • Pain around the heels or toes, around the knee, and in the lower back

How do I know if I have spondyloarthritis?

It is important to get an accurate diagnosis as quickly as possible to make sure that the condition does not worsen. The best way to do this is by visiting your doctor and, if possible, getting a referral to visit a rheumatologist, a doctor who specializes in treating spondyloarthritis.

Some ways that your doctor can assess whether you have the condition is through reviewing your medical history, and conducting a physical examination or lab tests (such as blood tests and imaging tests).