Chilblains are an abnormal vascular reaction to cold. In cold conditions small arteries and veins narrow to conserve heat which is a normal response to low temperatures.
Chilblains occur upon rewarming when widening of the vessels is not uniform and, as a result, circulation is obstructed. This causes a small red and superficial area of swelling to form. At various stages, chilblains can be white, blue, red or purple and can be numb, itchy or throbbing.
Chilblains can occur on the fingers, toes, heels, lower leg, nose or ears. They may be singular or multiple and will usually resolve within 3-5 weeks. Sometimes this does not occur and the chilblains will breakdown or even ulcerate.