Axial Spondyloarthritis Versus Degenerative Disc Disease
Reviewed by: HU Medical Review Board | Last reviewed: October 2022 | Last updated: April 2023
Axial spondyloarthritis (axSpA) and degenerative disc disease (DDD) are spine conditions that share many of the same painful symptoms. Sometimes it is hard for doctors to tell the 2 conditions apart. But even though they may look and feel similar, there are some important differences between them.1,2
What is degenerative disc disease?
When you are young, rubbery discs between the vertebrae of your back allow you to twist and bend. They also give you height. These discs start to wear down as you age. By age 40, most people have some disc degeneration.1
Sometimes, a disc fully wears away, which causes bone to rub against bone. The result is pain and stiffness. There are a few causes of DDD (also called spondylosis or osteoarthritis):1
- Age-related disc dryness
- Tears on the surface of the disc from day-to-day activities
There is not much blood supply to the discs in your back, so they cannot repair themselves if they are injured. An injured disc will start to wear away for good.3
You usually feel the symptoms of DDD in your lower back and neck. Pain ranges from mild to severe, and it may come and go. Pain also tends to worsen as you sit, bend, lift, or twist. It can spread to your:1-3
Weakness in your leg muscles or trouble lifting the front part of your foot (called foot drop) could be a sign of nerve root damage.1,3
How are axial spondyloarthritis and degenerative disc disease similar?
AxSpA and DDD can look alike, even to doctors. They share many of the same symptoms. Both conditions can cause:1-3
- Pain in the lower back
- Pain that spreads to the neck and buttocks
- Pain that comes and goes
The conditions may also look similar on X-ray and MRI images. Doctors use these images to look for changes to the spine that are linked to a form of axSpA called ankylosing spondylitis (AS). But these changes can happen because of damage from DDD as well as AS. Studies have shown that some people who were thought to have AS actually had DDD.4
Other similarities between DDD and axSpA include:5,6
- People with AS have a higher risk of hardened and narrow arteries (atherosclerosis). This condition also plays a role in DDD since arteries supply some blood to discs.
- People with AS and DDD may have higher levels of enzymes that break down cartilage and tissue in bones.
How are axial spondyloarthritis and degenerative disc disease different?
Although these conditions can look the same, there are some key differences:1-4,7
- AxSpA is caused by your genes and things in your environment. Degenerative disc disease happens when 1 or more discs in your back wear down.
- AxSpA typically appears before age 40. DDD usually happens later in life, after age 40.
- AxSpA pain is due to inflammation. DDD pain happens because of a lack of cushioning between discs in the spine.
- Inflammation from axSpA can cause symptoms other than pain. These may include lack of energy, anemia, bowel problems, and eye inflammation (uveitis).
How are the conditions treated?
Treatments for axSpA and DDD differ, but there is some overlap. Both conditions can be treated with:1-3
- Anti-inflammatory drugs
- Physical therapy
- Lifestyle changes, such as daily exercise
However, because AS is an autoimmune condition, treatment also includes the use of biologic drugs.1-3
There are also surgical treatment options for both axSpA and DDD. If their pain is severe, people with DDD may need to have surgery on the affected disc. Surgery may be needed with axSpA as well, though it is not as common and usually involves a hip joint replacement.1-3