They are generally a result of poor circulation, which can be aggravated by smoking. Chilblains are areas of itchy, purple-red, swollen skin. They are caused by hypersensitivity to cold. When the skin of a cold-sensitive child is exposed to cold and damp, the blood vessels beneath the skin close up to conserve heat, causing the skin to become numb and pale. When the blood vessels dilate again with warmth, the skin becomes red and itchy.
Chilblains usually appear toes and fingers and on the back of the legs.