Aural Hematoma in Dogs

Overview of Aural Hematoma in Dogs

Aural hematoma, commonly referred to as “pillow ear”, is an accumulation of blood within the cartilage layers of the dog’s ear. They usually appear as fluid-filled swellings on the concave (underneath) surface of the pinna, which is the pointed or floppy portion of the ear. The exact cause is poorly understood but any condition that leads to head shaking or ear scratching such as bacterial ear infection or ear mites may be responsible.

Aural hematomas can be painful to the touch and may aggravate an underlying ear disease. Left untreated, the swelling may eventually resolve on its own, leaving the ear deformed, a so-called “cauliflower ear.”

What to Watch For

Diagnosis of Aural Hematomas in Dogs

On a physical examination, a warm, fluid-filled swelling is noted on the inner surface of the ear. Eventually, the hematoma may become firm and thickened, resulting in a deformed “cauliflower” appearance.

Concurrent ear disease like infection or foreign material is common, but not always present.Radiographs of the skull may be indicated if your veterinarian suspects external or middle ear disease is present.Evaluation of the ear may show bacteria, yeast, ear mites, or foreign material to be present. Abnormalities in laboratory tests (blood work) are uncommon.

Treatment of Aural Hematoma in Dogs

The underlying ear disease must be treated appropriately.
Needle aspiration of the hematoma usually resolves the problem only temporarily. Recurrence is common with this technique.Surgical treatment is usually indicated.

Home Care and Prevention

Take your pet to a veterinarian to have the hematoma evaluated and to determine whether there is any underlying ear disease.

Delaying treatment will rarely result in a satisfactory or cosmetic outcome and fails to address the reason why the hematoma occurred in the first place.Check your pet’s ears frequently, at least once a week, for evidence of inflammation such as redness, swelling or pain.See your veterinarian as soon as head shaking, ear scratching or ear rubbing begins.

In-depth Information on Canine Aural Hematomas

Very few other medical problems resemble an aural hematoma. The fluid-filled swelling of the pinna is characteristic. Occasionally, an abscess or a tumor of the pinna might have a somewhat similar appearance.


An abscess may occur secondary to a penetrating foreign body or a bite wound. An infection could become established between the cartilage plates leading to the formation of a pocket of pus. Differentiation from a hematoma is simple, using needle aspiration. The abscess produces yellow or green pus; the hematoma yields blood.


A tumor of the pinna requires needle aspiration to obtain cells for examination on a slide, under a microscope. Differentiation between a bloody or fluid-filled tumor from a hematoma may be possible with this technique. Failing this, a biopsy specimen may be obtained. Tumors of the pinna are normally firm, fleshy or ulcerative (bleeding) and, therefore, quite different from an aural hematoma.

Veterinary care should include diagnostic tests and subsequent treatment recommendations.

Diagnosis In-depth

Your veterinarian will evaluate the ear closely and will palpate (feel) the swelling.

Your veterinarian will also examine the external ear canal. Visual inspection of the ear canal may be followed by otoscopic examination. Some dogs may tolerate this procedure quite well, but others may resist and squirm, necessitating sedation or even general anesthesia. For this reason, a detailed examination of the ear canal may be done at the time of surgical treatment of the hematoma.Visualization of the horizontal and vertical ear canal, together with the tympanic membrane or ear drum, is essential as part of the work-up for an underlying cause of the aural hematoma. Cultures may be obtained at this time to see what bacteria or fungi are growing in the ear and to what medications it is sensitive. Cotton-tipped swabs can obtain samples from the ear canal, be smeared onto a slide and evaluated under a microscope for parasites such as ear mites and yeast.Skull radiographs, in cases where underlying external or middle ear disease is suspected, are also obtained under general anesthesia. Radiographs are only necessary if the canal is narrowed and occluded, preventing visual evaluation of the ear drum. When available, computed tomography (CT scan) or magnetic resonance imaging (MRI) can be more helpful than radiography to evaluate involvement of the middle ear.

Treatment In-depth

Medical management by needle aspiration is rarely successful. Injection of steroids into the empty pocket, following drainage, has been reported. Recurrence with these techniques is extremely high.
Surgery aims to remove the hematoma, prevent recurrence and retain the natural appearance of the ear.The most common surgical technique involves making an S-shaped incision on the concave surface of the ear, over the hematoma, exposing the underlying cartilage from one end to the other. Blood and clot from within the swelling would be flushed out.Prior to surgical management, your pet should receive a thorough preoperative examination. At this time, blood may be drawn to check a variety of body systems before receiving general anesthesia. A urine sample and chest radiographs may also be necessary depending on your pet’s age and level of health.Under general anesthesia, the ear will be evaluated and, if necessary, cultured, and the ear canal will be cleaned and flushed.Sutures are placed through the skin on the concave surface, either through both cartilage plates and below the skin, or through both plates and out through the skin, and then back to the concave surface. The sutures are about 1 cm in length and run parallel to the major vessels of the ear; that is vertical, not horizontal. A sufficient number of sutures are placed around the incision to obliterate any remaining fluid pockets.Your veterinarian will NOT suture the incision closed. Instead, it will gap slightly to allow for drainage.Some veterinarians may prefer to insert a narrow (1/4 inch) latex rubber drain into the swelling, leaving this in place below a dressing for the ear for 10 to 14 days. The dressing will help apply pressure and the drain prevents fluid accumulation. A teat cannula, originally designed for use in milking cows, can be modified for the same purpose. Both alternatives work well, and your veterinarian may have had good success with these methods.A bandage can be used to protect the ear following hematoma surgery, but maintaining the bandage can be difficult. Patient tolerance for the bandage is often limited. When a bandage is used, the ear is placed over the top of the head, with non-adhesive dressings and cotton padding to protect the surgical site and offer gentle compression. Vetrap® or stockinette can be used as the outer layer. An Elizabethan collar may be a better alternative for many dogs. Where medications are required for the ear following surgery, the bandage can be a problem in that it restricts access to the ear canal.

Follow-up Care for Dogs with Aural hematoma

A veterinary consultation should be sought as soon as an aural hematoma is discovered, although this is NOT a surgical emergency in dogs.
Complete the course of medications (topical, oral or both) for the treatment of an underlying ear disease, if one was found.Where a bandage is used, check under the neck region to make sure it is not too tight and does not interfere with breathing.Monitor your dog for tolerance of a bandage or collar. Call your veterinarian if this is a problem.When there is no bandage, check the incision daily for excessive swelling or redness. A watery, bloody discharge is considered normal for the first few days following surgery.Return to your veterinarian in 10 to 14 days for suture removal. Most dogs will tolerate this procedure without the need for sedation.Check your dog’s ears frequently, at least once a week, feeling around the base of the ear for any pain or discomfort and looking down the ear canal for waxy build up, redness or any other type of discharge. The ear canal should be open, clean and not inflamed. If it is inflamed, you should consult with your veterinarian. Do not be tempted to probe the ear yourself with something like a Q-tip, as it is possible to damage inadvertently the canal or ear drum. If your pet has a history of ear infections, this type of monitoring will be even more important.At the earliest signs of head shaking, consult with your vet. Very few dogs that actually have outer ear disease go on to get an aural hematoma, but addressing the underlying ear problem early will help to prevent the occurrence of this troublesome secondary disease.