An aural hematoma is a collection of blood, either fresh or clotted, within the pinna (ear flap). When a hematoma is present, the pinna will appear very thick and spongy. The swelling may involve the entire pinna or it may involve only one area of the ear.

How did my cat get a hematoma?

The external ear has a layer of skin on both sides and a layer of cartilage sandwiched between the two skin layers. Blood vessels run just beneath the skin. When something irritates the ear canal, the cat responds by scratching or shaking its head. Excessive or violent shaking causes one or more blood vessels to break, resulting in bleeding into the space between the ear cartilage and skin on the inner surface of the ear.

How is an ear hematoma treated?

As well as treating the hematoma, it is important to treat the underlying cause of the aural hematoma. The majority of cats that develop a hematoma have an infection or other inflammatory ear condition that caused the excessive scratching and head shaking. In some cases, there may be a piece of foreign material lodged in the ear canal such as a tick, piece of grass, etc. It is also possible that a foreign body initiated the shaking but was later dislodged. Cats with a bleeding or clotting disorder may also develop an aural hematoma, with or without a history of trauma.

“The hematoma should be treated as soon as possible to minimize the chance of permanent disfigurement of the ear.”

The hematoma should be treated as soon as possible to minimize the chance of permanent disfigurement of the ear. Most ear hematomas are treated with surgery. The actual surgical technique varies with the individual circumstances and veterinarian’s preference but always involves the same basic steps.

• The blood is removed from the pinna. This is accomplished by making a small incision at each end of the hematoma. A drain tube may be passed through the hematoma and sutured to the ear to remove any more blood or serum that accumulates in the area. Alternatively, the skin over the hematoma may be incised and opened completely. This is more likely to be used for more serious hematomas and for those in which the blood has clotted.
• Space, where the blood accumulated, is obliterated. Since the skin over the hematoma has been pushed away from the cartilage, it must be reattached to it to prevent another hematoma from occurring. This is accomplished by placing a series of sutures (“stitches”) that are passed completely through the ear flap.
• The pinna is stabilized to prevent further damage. Shaking after the ear pinna has been sutured at this time may cause further damage to the ear. In some cases, the pinna is laid on top of the cat’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.

Once the hematoma has been surgically corrected, if an underlying cause is found, such as an infection, an allergy, or a foreign body, it will be treated.

What follow-up treatment is needed?

Drainage tubes or bandages may be removed by your veterinarian after three to fourteen days. In some cases, there may be one or more drainage holes from the drain or incision, which will be left to heal by scar tissue. The sutures may be removed after 2 weeks if the ear is completely healed; in severe cases, some or all of the sutures may be left in place for up to two weeks longer. If discharge occurs from the surgery sites before they close, it should be cleaned off with mild cleansing soap.  If an infection was present, it will be necessary to recheck the ear canal to be sure that the infection is gone. Otherwise, another hematoma may occur.

If it is a blood blister, won’t it disappear with time, just like a bruise?

If left untreated, the hematoma may be slowly reabsorbed, but the associated inflammation damages the surrounding ear tissues and resulting in a distorted, cauliflower-shaped ear. Aural hematomas are very painful, and for humane reasons, they should be treated.

Can you just drain the swelling?

Drainage may result in a temporary correction, but the hematoma returns within one to two days in the vast majority of cases. The longer the hematoma is left untreated the greater the likelihood of permanent damage and disfigurement. Drainage may be used if the hematoma is very small, or if the patient cannot undergo surgery for some reason. Anti-inflammatory medication is usually prescribed in these cases. The success rate is less than 50%.