The disease most commonly begins between 16 and 40 years of age. Back pain is the usual presenting symptoms. Its onset is gradual and is often accompanied by constitutional disturbances. The pain usually disturbs sleep and is associated with morning stiffness and stiffness after immobility. In the late stages of the disease, there may be reduction in spinal pain as the axial skeleton becomes ankylosed.
Symptoms improve with exercise.
Diagnosis is often delayed, symptoms being ascribed to lumbar disc disease. Although primarily an articular disease of the axial and peripheral skeleton, other organs may be involved. Iritis may be a presenting feature. Aortitis and myocarditis are causes of death. Patients with severe ankylosing spondylitis may exhibit chronic fibriotic changes in the upper lung that resemble tuberculosis.