||The pinna, by virtue of its exposed location, presents a large surface area in relation to its blood supply and is consequently subject to damage from extreme cold.
The effect of cold temperature is increased by exposure to wind and by the presence of moisture on the exposed skin.
Exposure to very low temperatures causes a severe and prolonged vasoconstriction of the capillary walls, resulting in damage to these walls.
The anaesthesia which occurs in those areas of the skin exposed to the cold allows a significant amount of damage to occur “silently” without the patient's knowledge.
The superior third of the pinna is most commonly affected by frostbite.
Frostbite is usually characterized by a reddish or blue discoloration of the pinna, often accompanied by serum-filled blisters which resemble a second-degree burn.
A frostbitten ear should be gradually rewarmed and protected by a sterile dressing in order to prevent the development of secondary infection.
Early surgical debridement is best avoided, since it may take several months for the delineation between viable and dead tissue to occur.