An aural (ear) hematoma is a collection of blood, serum, or clotted blood within the pinna (earflap). When present, the pinna will be very thick. The swelling may involve the entire pinna or it may involve only one area.
The earflap is composed of two layers of skin surrounding a layer of cartilage. The cartilage gives the earflap its shape. Blood vessels go from side-to-side by passing through the cartilage. Violent head shaking or an injury to the pinna can cause the vessels to break; however, in some cases, the cause remains undetermined.
The cause of aural hematomas is often unknown. Vigorous shaking of the head and ears has been thought to be responsible, yet a large percentage of affected animals develop hematomas without shaking their head. Disease of the ear canal is also considered to play a role, but not all animals with aural hematomas have ear disease (otitis). Scratching or biting of the ears can also cause aural hematomas.
The most consistent clinical sign is a thickened earflap. The pet may have a history of head shaking. Debris or odor may occur in the ear canal if an infection is present. Ear mites could be found to be an inciting factor.
A physical examination of the earflap is usually all that is needed to make the diagnosis.
There are two approaches to treatment: a medical approach and a surgical approach
This is the simplest and least invasive procedure; however, it is not always successful. Surgical treatment is warranted if medical treatment fails.
The blood in the earflap is aspirated with a syringe and needle. One of several medications, often a cortisone-type drug, is injected into the space from which the blood was taken. The earflap is taped over the head in dogs. The pet is checked in 3-7 days to assess the outcome of treatment. If ear mites have been observed or an ear infection is present, those conditions are also treated.
There are several surgical approaches to the treatment of aural hematomas. The blood is removed from the pinna through an incision(s). The incision is then either left open or a rubber drain tube (or cannula) is passed through the hematoma and sutured to the ear. This assures drainage of any more blood or serum that accumulates in the area.
Since the skin over the hematoma has been pushed away from the cartilage, it must be reattached to prevent another hematoma from occurring. The space where the blood accumulated is obliterated by placing a series of sutures that are passed through the earflap.
The pinna is stabilized to prevent further damage. In dogs, the pinna is laid on top of the dog's head and bandaged in place. Although the bandage may be somewhat cumbersome, it will prevent further damage to the pinna and allow proper healing to progress. Since cats have erect ears, it mey not be necessary to bandage their ear in place. The use of an Elizabethan collar is essential to keep the pet from damaging their ear further or removing their bandage.
Another important aspect of treatment is dealing with the cause of any potential head shaking or scratching. The ears should be examined for infection, ear mites, or foreign bodies, and appropriated treatment should be started.
The drain tube or cannula is generally removed in about 3-5 days, and the bandage and sutures are removed in about 10-14 days.
If an infectionor infestation was present, it will be necessary to recheck the ear canal to be sure that the infection is gone. Otherwise, another hematoma may occur.
Usually the prognosis is good for recovery, but it is not uncommon for the hematoma to recur at least once.