Phenomenon, Raynaud's

A condition resulting in discoloration of fingers and/or toes when a person is exposed to changes in temperature (cold or hot) or emotional events.

The skin discoloration occurs because an abnormal spasm of the blood vessels causes a diminished blood supply.

Initially, the digits involved turn white because of diminished blood supply, then turn blue because of prolonged lack of oxygen and finally, the blood vessels reopen, causing a local 'flushing' phenomenon, which turns the digits red.

This three-phase color sequence (white to blue to red), most often upon exposure to cold temperature, is characteristic of Raynaud's phenomenon.</P> NTER><IMG height=326 alt='Raynaud's Phenomenon illustration' src='http://images.medicinenet.com/images/ABRAYNA.GIF' width=305></CENTER> Raynaud's phenomenon occurs with a number of conditions including rheumatic diseases (scleroderma, rheumatoid arthritis, systemic lupus erythematosus), hormone imbalance (hypothyroidism and carcinoid), trauma (frostbite, vibrating tools), medications (propranolol/INDERAL, estrogens, nicotine, bleomycin) and, rarely, cancer.</P> The phenomenon is named for the French physician Maurice Raynaud (1834-1881).