Definition of Reactive arthritis

Reactive arthritis: A chronic form of arthritis featuring the following three conditions: (1) inflamed joints; (2) inflammation of the eyes (conjunctivitis); and (3) inflammation of the genital, urinary or gastrointestinal system.

Reactive arthritis is the preferred name for what was called Reiter's syndrome since it is thought to involve the immune system which is "reacting" to the presence of a bacterial infection in the genital, urinary, or gastrointestinal system. Accordingly, certain people's immune systems are genetically primed to react aberrantly when these areas are exposed to certain bacteria. The aberrant reaction of the immune system leads to inflammation in the joints, eyes, and genital, urinary or gastrointestinal system.