In Raynaud's phenomenon, smaller arteries that supply blood to the skin constrict excessively in response to cold, limiting blood supply to the affected area.
The fingers, toes, ears, and tip of the nose are commonly involved and feel numb and cool in response to cold temperatures or stress. It's often accompanied by changes in the color of the skin.
Treatment beyond self-care, such as dressing warmer, usually isn't needed.
Consult a doctor for medical advice
Sources: Mayo Clinic and others.
More than 200,000 US cases per year
Treatable by a medical professional
Lab tests or imaging often required
Chronic: can last for years or be lifelong