Raynaud’s phenomenon is a disorder of blood circulation in the fingers and toes (and less commonly of the ears and nose). It affects small arterial vessels causing them to collapse due to exposure to cold, emotional stress or vasoconstrictive agent (medication or smoking).
Abnormal nerve control of the blood-vessel diameter causes small capillary to collapse (A). Finger colour first turns white (B) due to lack of blood supply, then blue (C) due to lack of oxygen. Frequent attacks can lead to serious lack of tissue oxygen at fingertips and thrombosis that can result in tissue death – gangrene (see picture below).
Raynaud’s phenomenon (RF) can be seen also with: rheumatoid arthritis, scleroderma, lupus erythematosus, frostbite, hormone imbalance and cancer.
Image source: National Heart Lung and Blood Institute