Canities subita

Canities subita, also called Marie Antoinette syndrome or Thomas More syndrome, is an alleged condition in which hair turns white over a short span, attributed to extreme stress or trauma. Its popular names come from historical cases, including Queen Marie Antoinette of France, whose hair was reported to have turned stark white overnight after her capture following the failed flight to Varennes during the French Revolution, and Sir Thomas More, whose hair reportedly turned white the night before his beheading. Although a number of cases of rapid hair greying have been documented, the underlying physiological changes have not been sufficiently studied.