Raynaud's phenomenon is a condition where blood flow to toes and fingers, nose and ears, is restricted by spasms in the blood vessels, leaving the sufferer feeling cold. Fingers can turn blue and white from things most of us would consider moderately cool. The fingers will turn red when circulation begins again.
“ 'Five to seven percent of all otherwise healthy women have primary Raynaud’s,' the most common form that occurs without any underlying disease, said Dr. Robert Simms, a rheumatologist at Boston University. 'It’s considered part of a spectrum of responses to cold exposure.' Symptoms typically first arise between the ages of 15 and 30, but no one knows what causes the abnormal physiologic response to cold."
In many cases, the condition is a nuisance that necessitates wearing gloves when it's a bit cool out and putting on an extra pair of socks. Extreme cases of Raynaud's can turn out to be the first indication of lupus or scleroderma, which are autoimmune diseases.