What is Ankylosing Spondylitis?
Ankylosing spondylitis (pronounced ANK-ki-low-sing spon-di-LIE-tis), or AS, is a lifelong autoimmune disease — and form of arthritis —
that causes inflammation, pain, and stiffness mainly in the spinal joints. AS symptoms can be confused with symptoms of mechanical back pain,
which are primarily in the lower back. AS symptoms often start in the lower back, and can be difficult to diagnose, or are often not properly diagnosed at all.
Inflammatory Back Pain vs Mechanical Back Pain
There are 2 types of back pain:
Mechanical Back Pain. Caused by a specific injury or strain to the back, like lifting too much weight. Mechanical back pain is very common, occurring at least once in 85% of adults younger than 50. Mechanical back pain can be distinguished by:
- Being alleviated by bed rest
- Lasting less than 4-6 weeks
Inflammatory Back Pain. Caused by inflammation in the spinal joints, and not a result of any specific injury.
The back pain associated with AS is inflammatory in nature. Some symptoms to help determine if your back pain can be related to an inflammatory condition like AS are:
- Back pain and stiffness worsen with rest or inactivity, with pain often occurring at night or early in the morning
- Back pain and stiffness tend to be eased by exercise or movement
- Back pain lasting more than 3 months (chronic)
Disease impact
In the early stages of AS, the pain and stiffness often starts in the lower back,
but over time, it may move up the spine and into the neck. Patients with active disease experience greater levels of pain, swelling, and discomfort and may experience morning stiffness.
AS symptoms vary from person to person, and can have a wide range of effects.
One person's experience could be completely different from another person's. For some people, over time, AS can lead to fusion of spinal joints. In the more severe cases, AS can result in a forward-stooped posture.
Learn more about AS symptoms and how AS affects the body.
Who's at risk?
Ankylosing spondylitis affects men more than women, and disease onset usually occurs
before age 35 — peaking around age 28. A family history of AS can also increase risk of developing the disease.
Learn about other AS risk factors and potential
AS causes.
Unfortunately, diagnosing AS can be difficult. That's why it's important to learn as much as you can about the disease and to talk to your doctor about your back pain