Definition of Phenomenon, Raynaud's

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 of Raynaud's phenomenon.

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.

The phenomenon is named for the French physician Maurice Raynaud (1834-1881).