Reactive arthritis is one of the family of spondylitis diseases. I have Ankylosing Spondylitis which is also a spondylitis disease. There is wonderful information about these diseases on the Spondylitis Association of America website. I have linked their name to their website so you can learn a little more about them. On the header on their home page is a link to "about Spondylitis"...that's where you need to go.