Raynau's phenomenon (pronounced /reɪˈnoʊz/) (rāy-NŌZ), in medicine, is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other extremities, named for French physician Maurice Raynaud (1834 - 1881). The cause of the phenomenon is believed to be the result of vasospasms that decrease blood supply to the respective regions. Emotional stress and cold are classical triggers of the phenonmenon, and the discoloration follows a characteristic pattern in time: white, blue and red.