There is a broad range of symptoms caused by ankylosing spondylitis. Although symptoms can vary widely, the first symptoms typically noted by patients include:

  • Sacroiliitis, an inflammation of the sacroiliac joint where the spine attaches to the pelvis. This causes pain in the buttocks that can radiate down the thigh, but does not go past the knee.
  • Gradual onset of lower back pain, buttock pain or hip pain with stiffness over a period of weeks or months
  • Unlike back pain from other causes, pain from this type of arthritis is worse during periods of rest or inactivity. Patients may wake up from sleep with severe pain.
  • Early morning stiffness and limited movement which improve with a warm shower or light exercise
  • Tenderness over the inflammation site (most often over the first joint of the lowest part of the spine, the sacroiliac joint)
  • Weight loss and/or loss of appetite
  • Unexplained fatigue
  • Fever and night sweats
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Changes in the Location of Joint Pain

The initial pain caused by ankylosing spondylitis is not always located in the lower back. For example, females have reported experiencing pain in the neck more frequently than males. Children almost never experience pain in the back, but rather in their heels or knees.

In addition to lower back involvement, other symptoms include:

  • Joint pain. 50% of patients with ankylosing spondylitis will develop inflammation of joints in the arms and legs. Inflammation that causes knee pain, shoulder pain, or ankle pain is most common.

  • Enthesitis. Inflammation of the spots where ligaments and muscles attach to bones is a common source of pain, stiffness and restriction of the joints. In addition to the spine, enthesitis affects the plantar fascia of the foot and the Achilles tendon.
  • Eye pain. Eye inflammation (iritis) occurs in 25% of ankylosing spondylitis patients. Iritis causes redness and eye pain and can be a serious condition. Iritis requires immediate attention by an ophthalmologist.
  • Respiratory difficulty. The rib cage may fuse which can limit normal expansion of the lungs and cause breathing difficulties.
  • Cardiac problems. Rarely, ankylosing spondylitis can affect the heart.

  • Shoulder and knee stiffness. As stiffness in the lower back limits the patient’s movement, flexibility in these smaller joints also decreases.