The bottom line: RS3PE etiology is not known; however, there are many factors that may play a role in its development. It has been hypothesized that nvironmental factors or infectious agents may predispose to this condition.
Finnell Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome: a review of the literature and a report of three cases. The Journal of foot and ankle surgery 2000 vol:39 iss:3 pg:189 -193
RS3PE is a short duration illness, usually remitting within 18 months. The predominance is male and characteristically negative serological tests. Specific rheumatological laboratory tests including rheumatoid factor and antinuclear antibody are negative in the majority of patients.