Ankylosing spondylitis is a type of arthritis that causes inflammation in the joints and ligaments of the spine. It may also affect peripheral joints like the knees, ankles, and hips. Normally, the joints and ligaments in the spine help us move and bend. If you have ankylosing spondylitis, the inflammation in the joints and tissues of the spine can cause stiffness.
Many people with ankylosing spondylitis have mild episodes of back pain and stiffness that come and go. But others have severe, ongoing pain with loss of flexibility in the spine. In addition, other symptoms may develop depending on which other areas of the body are affected by the disease. Some people with ankylosing spondylitis develop eye disease (uveitis), skin disease (psoriasis), or gut disease (inflammatory bowel disease).