Chorea.

Two weeks after starting the oral contraceptive pill, a 16-year-old girl developed increasingly violent chorea and an evolving psychosis with prominent hallucinations, ideas of reference, and paranoia. An erythematous skin rash subsequently developed and Sydenham's chorea (SC) was diagnosed. Following neuroleptic medication and steroids, her chorea and psychosis subsided. This case illustrates that severe psychotic features can occur in SC. It is recommended that antistreptolysin O titres and antibasal ganglia antibodies are checked early in patients with evolving movement disorders and prominent neuropsychiatric features, as the window for modifying the course of this immune-mediated disorder may be narrow.