Frostnip occurs when skin surfaces, such as the tip of the nose and ears, are exposed to an environment cold enough to freeze the epidermis. These prominent exposed surfaces become blanched and develop paresthesia and numbness but remain pliable. As they are rewarmed, they become hyperemic and are usually very painful. Pernio (chilblains) is an inflammatory skin injury caused by exposure to cold (often repeatedly) above the freezing point and may be idiopathic or secondary to connective tissue disease or cryoglobulinemia.