Auli Toivanen, MD and Paavo Toivanen, MD
Reactive arthritis is a disease affecting mostly young adults. Owing to a greater general awareness the diagnosis has become more common during recent years. It is well established that ReA is caused by an infection, mostly in genetically susceptible individuals. The pathogenetic mechanisms are still poorly understood, and the treatment rests mainly on anti-inflammatory drugs or steroids. Vigorous and early treatment of the triggering infection may prevent the development of ReA but this is rarely possible in everyday clinical practice. Despite its name, the disease should be considered as a general disorder that affects not only the joints. The prognosis is not as good as earlier believed, and relapses or chronic development are not unusual.