Raynaud's phenomenon is a disorder in which the blood vessels to the fingers and toes (digits) become abnormally closed off (constricted). The fingers and toes of individuals with Raynaud's phenomenon change color from white to blue to red, often causing them to feel numb. Raynaud's phenomenon is sometimes seen with autoimmune diseases, such as rheumatoid arthritis, scleroderma, and lupus, where the body's immune system turns against itself, causing various symptoms. Other causes of Raynaud's phenomenon include repeated trauma/vibration, abnormalities in the structure of blood vessels, and drug injection into one type of blood vessel (arteries).
During the winter months, I hear a lot of concern from patients about frostbite. Frostbite is a very real danger in extremely cold weather. However, patients often confuse other dermatological conditions – such as frostnip, Raynaud’s phenomenon, and pernio – with frostbite. I hope to clear up some of the confusion by explaining these conditions here.