Ankylosing spondylitis is characterized by inflammation and swelling of the spine and the sacroiliac joints. It affects other body parts like eyes, heart, lungs and kidneys. It results from some genetic factors especially HLA-B27 and frequent gastrointestinal infections. The symptoms of ankylosing spondylitis begin in early adulthood between the age-group of 20-30 years. However, they may occur in early childhood or much later.

The most prominent symptoms of ankylosing spondylitis are diffused pain and stiffness in the buttocks and lower back. The pain and stiffness may become worst in the morning and during night and may be improved by light exercise or warm shower. The pain may worsen after prolonged sitting or rest and may improve with exercise and activity. Other symptoms associated with early stages of ankylosing spondylitis are loss of appetite, mild fever and general discomfort.

Inflammation of spine may give rise to stiffness and pain in low back, neck, upper buttock area and remaining area of spine. The severity of symptoms and complications may vary patient to patient. Patients with severe and chronic inflammation of spine may give rise to total bony fusion of spine which is known as ankylosis. It can lead to complete loss of mobility of spine. There may be difficulty in walking or standing. These fused spines are brittle and susceptible for fractures. The lower neck (cervical spine) is more vulnerable area for fractures. Sometimes, patients with ankylosing spondylitis can develop Achilles tendinitis which may cause stiffness and pain in the back of heel. In addition to that, plantar fasciitis (inflammation of tissues of bottom of foot) is frequently found in people with ankylosing spondylitis.

Other symptoms of ankylosing spondylitis are associated with involvement of other organs. When the disease becomes chronic and severe, there may be cause forward curving of the upper torso (thoracic spine) which can reduce the breathing capacity. There may be inflammation and scarring of the lungs due to ankylosing spondylitis which may cause coughing and shortness of breath. Breathing difficulty can be one of the serious complications of ankylosing spondylitis.

Advanced ankylosing spondylitis can cause deposition of protein material known as amyloid into the kidneys resulting in kidney failure. Progressive kidney disease can give rise to nausea and chronic fatigue. Besides this, if the heart is affected by this disease, there may be valve problems such as aortitis (inflammation of the largest artery, aorta). Inflammation of other body parts can give rise to some other conditions such as inflammatory bowel disease, anemia and iritis (painful and inflamed eyes).