Very different. Reactive arthritis (previously called reiter's disease) is a self-limited arthritis that develops as an autoimmune response to an infection (some diarrheal infections, some sexually transmitted infections, some respiratory infections).Very painful swollen joints, sometimes with eye inflammation (uveitis), and urethral inflammation.Still's disease is systemic jia when in kids and is a chronic disease.
Reactive Arthritis. http://en.m.wikipedia.org/wiki/reiter_disease. http://www.medicinenet.com/script/main/mobileart.asp?articlekey=927.