"or bring on an attack of St Vitus' dance"
8 year old American girl who suffered from St. Vitus Dance (1913)
Public Domain8 year old American girl who suffered from St. Vitus Dance (1913) - Credit: Lewis Wickes Hine (U.S. Library of Congress)

 St. Vitus Dance is the old name for an illness which usually occurs in children and teenagers under eighteen. It is often linked to rheumatic fever.

The face, feet and hands of those suffering from St. Vitus Dance will jerk uncontrollably. Those with the illness may also have trouble walking and writing, and suffer from headaches.

The jerky movements stop when someone is asleep, and the illness usually goes away of its own accord after a few months.

Today, the illness is called Sydenham's chorea or chorea minor.