SYMPTOMS AND CAUSES OF ANKYLOSING SPONDYLITIS
Early symptoms of AS
The first symptoms of ankylosing spondylitis are usually pain and stiffness in the lower back and buttocks. However, sometimes, the pain may start in the neck rather than the back, especially in women.
Pain and stiffness may only be felt on one side or on alternate sides. Usually symptoms appear gradually, over a few weeks or months and can come and go (or “flare up”), eventually becoming persistent, chronic pain on both sides. It’s important to note that ankylosing spondylitis varies from person to person, and the onset of symptoms does, too.
Common AS symptoms
The pain AS causes lasts longer than 3 months, and you might notice the stiffness and pain are worse after you’ve been resting or sitting.
- Pain feels worse when resting
- Pain is alleviated when moving
- Back feels stiff upon awakening
If any of these symptoms sound familiar, talk to your doctor. Over time, AS can start to worsen. It may even begin to restrict your spinal movement and, in more severe cases, cause fusing of the spine.
Other symptoms may include:
- Fatigue The body uses energy to fight the inflammation of AS, and nighttime symptoms may affect sleep, which can contribute to fatigue.
- Peripheral joint pain In a minority of individuals, pain does not start in the lower back, or even the neck, but in a peripheral joint such as the hip, ankle, elbow, knee, heel, or shoulder.
- Loss of appetite In early stages of AS, individuals can experience loss of appetite.
- Sacroiliac joint inflammation This is a common AS symptom. Sacroiliac joints are located at the base of the spine where it meets the pelvis.
Other areas where AS can affect you
AS often affects the area where connective tissues, such as ligaments and tendons, attach to bone. This area is called the enthesis. Enthesitis is inflammation in those areas. Click or tap on the hot spots to show where AS can affect you.

NECK
Women in particular may feel symptoms in the neck before the lower back
SHOULDER BLADES
Inflammation can progress to include the shoulders
RIBS
In severe cases, ribs can fuse together, making breathing more difficult
LOWER BACK
Frequent pain and stiffness in the lower back and buttocks are the most common early symptoms
HIPS
Over time, AS can include pain and stiffness in the hips
Causes of ankylosing spondylitis
While the exact causes of ankylosing spondylitis are not understood, it is known that genetics plays a role. A protein called HLA-B27 is produced by a gene that is found in many people with ankylosing spondylitis. However, you do not have to be HLA-B27 positive to have AS; nor do the majority of people with this genetic marker have AS.
Scientists believe that other causes of ankylosing spondylitis may include:
- Other genes besides HLA-B27
- A triggering environmental factor, such as a bacterial infection
Other signs and symptoms associated with AS
If you have any of the following problems in addition to back pain and stiffness, make sure to tell your doctor.
- Family history of AS
- History of uveitis or iritis (inflammation of the eye)
- Frequent gastrointestinal issues that may be associated with Crohn’s disease or ulcerative colitis
- Itchy, flaky skin rashes or history of psoriasis
This information could be helpful to your doctor when ruling out or diagnosing AS.
Diagnosing AS is important, as advanced symptoms may include hunched posture, “bamboo spine” (the appearance of a spinal column that resembles bamboo), and a fused spine (when the spine fuses together), which can happen as a result of chronic progressive disease and uncontrolled inflammation.

“
I was in pain and thought I just needed to take it easy, but it was getting progressively worse.
”
Karen
Real AS patient

TAKE THE AS SYMPTOM
QUIZ
Find out if your back or neck pain and stiffness could be ankylosing spondylitis and then talk to your doctor about your symptoms.

FIND A
RHEUMATOLOGIST
If you have AS symptoms, talk to your doctor, who may refer you to a rheumatologist.