He has difficulty getting out of bed and has recurrent stiffness after sitting too long. His chest expansion and neck movements are reduced. Tapping over the sacro-iliac joints hurts. He has pain and swelling over the insertion of his heel tendon. Inquiry reveals a story of earlier discharge from the penis or a relative with psoriasis.
Symptoms improve as the day goes on or with exercise.
X rays may show inflammation where the sacrum meets the pelvis. The vertebrae look squarish rather than nipped-in at the waist. There is inflammation alongside the vertebral cushioning discs. If these areas calcify, the spine will look like bamboo. Lastly perhaps 2 to 4 peripheral joints may be involved rather than the many seen in rheumatoid arthritis, and usually only large joints.