||Hematoma of the auricle is typically the consequence of blunt trauma, such as boxing or twisting of the pinna. The skin on the lateral surface of the auricle is tightly attached to the underlying perichondrium, and the small vessels that lie in between the perichondrium and the underlying auricular cartilage are easily ruptured by a shearing force.
If a vessel is torn, blood extravasates in the subperichondrial plane to elevate the perichondrium from the underlying cartilage. The subperichondrial hematoma forms a soft blue or purple bulge that distorts the normal contours of the ear. If not aspirated or drained, the hematoma will persist, depriving the underlying cartilage of its perichondrial nourishment thereby producing avascular necrosis of the underlying cartilage. A frequent late sequela is organization of the hematoma with the development of a "cauliflower ear."