I started with a diagnosis of reactive arthritis (still called Reiter's Syndrome at the time), after an intestinal infection. After 10 years of feeling fine and unmedicated, but with occasional flare-ups, I suddenly went downhill and my diagnosis was changed to ankylosing spondylitis (modified New York criteria). To my knowledge, there is very little research on the separation or progression between reactive arthritis and ankylosing spondylitis.