Sydenham's chorea is an inflammatory reaction sometimes occurring after a streptococcal infection, although it may be associated with other conditions as well.In addition to chorea, the acute attack is almost always characterized by psychiatric symptoms such as irritability, obsessions and compulsions, tics and psychotic symptoms.
Chorea occurs most commonly between the ages of 7 and 14 years with the peak incidence at 8 years. It is rare after puberty and exceedingly uncommon after the age of 20 years. In the 1950's chorea occurred in approximately 50% of cases of acute RF. The incidence has declined substantially with chorea now being a component of less than 10% of cases of acute RF.