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. Ankylosing spondylitis emphasizes low back and shoulder involvement. Reiter's reactive arthritis may involve urethral discharge, eye inflammation, diarrhea, spondylitis, and inflammation in knees, ankles and toes.
Psoriatic arthritis involves a variety of joints and the skin.
Treatment has at least 4 components. The patient needs lifelong daily exercise to maintain spinal flexibility. The areas of aching enthesis may need steroid injection or support. The joint pain will respond to piroxicam or indomethicin. If ineffective more powerful drugs can be used.