Ankylosing spondylitis scleritis

Ankylosing spondylitis (AS) is a chronic systemic disease of unknown origin, involving the spinal joints, sacroiliac joints, and tissues around the joints. In the early years it was considered a clinical type of rheumatoid arthritis (RA). In recent years, this disease is considered to be an independent disease completely different from RA. Diseases that can cause spinal joint disease also include Reiter syndrome (RS), psoriatic arthritis, and inflammatory bowel disease (IBD).