Ear Hematoma in Dogs

A hematoma is defined as swelling created by a broken blood vessel after bleeding has occurred inside a tissue. Auricular or ear hematomas are fluid-filled swellings of various sizes that develop on the concave surface of ear of dogs, cats, and pigs. The condition is far more common in dogs than cats. The pathogenesis for the development of the lesions is not completely understood, but head shaking or ear scratching due to itching is thought to be the main cause. In dogs, the condition is frequently related to the presence of otitis externa (inflammation or infection of the external auditory canal, the auricle, or both). Treatment of ear hematomas usually requires a surgical intervention and medication to treat otitis externa. 

Ear hematoma's are fluid-filled pockets on the inside of the earflap. When something causes vessels to rupture, they bleed under the skin and form a fluid-filled pocket. Ear hematomas are commonly seen in floppy-eared dogs, but they can occur in any breed. A problem with a dogs ear is usually quite visible and a quick check-in with a veterinarian can confirm presence of a hematoma.

Dogs with this condition will present with a soft fluid-filled swelling in one or the two ears. The earflap will feel fluctuant, like a water balloon because it may be partially or completely swell with blood. The swelling will vary in size, in some cases it may be so large that the opening of the ear canal is blocked. The extra weight of the earflap may be uncomfortable for the animal and it may lead to a permanent change in the shape of the ears. Most animals will show signs of pruritus (itching) like head shaking and ear scratching.

• Otitis externa and trauma - It is thought that the presence of otitis externa leads to head shaking, which in turn, can lead to trauma. Head shaking can cause separation of the skin of the external ear cartilage, leading to vessel rupture and hematoma formation. However, hematomas may be found in cases where there is no obvious ear disease or trauma and be absent in cases of extreme otitis externa or pruritus, for example, in cases of Sarcoptes infestation.
• Autoimmunity - In 1986 Kuwahara proposed that the development of aural hematoma formation was due to an immune mediated process, based on the results of testing 40 affected dogs. However, there has been contradictory evidence for this theory.

Diagnosis of ear hematoma is based on the presence of unilateral or bilateral soft ear swelling that is filled with blood or bloody fluid. The veterinarian will collect a sample of the fluid inside of the swelling using fine needle aspiration in order to make the diagnosis. In addition, it is important to diagnose what is causing the condition. Otitis externa can be diagnosed if there is bad odor on the ears, excessive secretion, and/or inflammation. A bacterial culture and other laboratory analysis may be needed to determine what is causing the otitis and to choose the best treatment option available. The canal must be visually examined with an otoscope.

Any underlying ear infection needs to be addressed.

Mild heamatomas may be drained with a needle in the conscious pet but re-filling is relatively common. Injecting the area with steroids may prevent re-filling.

Ear hematomas usually require surgical treatment. The surgery requires general anesthesia and consists of making an incision in the affected ear in order to drain all the fluid that has been accumulated between the skin and the auricular cartilage. Several sutures (the amount will vary depending on the size of the hematoma) are placed parallel to the line of incision to minimize the chance of damaging the ear blood vessels and to promote adhesion of the skin to the ear cartilage. The incision will remain open to allow drainage of the ear. Some veterinarians will place a pressure wrap for seven days on the ear to promote further drainage and prevent re-accumulation of fluid in the ear. Pressure wraps following surgery is not usually required in cats, and is not often tolerated. Sutures will be removed 14-21 days after the surgery. The veterinarian will prescribe pain medication, antibiotics and other medication required to treat otitis externa, if present.

This procedure is relatively safe and animals have a good prognosis, however, there are some risks associated to general anesthesia as with any other surgery. Early diagnosis and intervention ensures a good outcome so it is essential to contact the veterinarian as soon as you observe signs of ear hematoma.

After the surgery the veterinarian will give you indications about the postoperative care and monitoring. Some of the recommendations may include:

• The ear canal should be cleaned, dried and treated with an appropriate medication at the end of the procedure.
• Clean the incision and massage out any small pockets of fluid that accumulate postoperatively.
• Using an Elizabethan collar until the sutures are removed and the hematoma and otitis externa are resolved.
• Adequate treatment and consistent follow-up of otitis externa, if present.

The prognosis for resolution of aural hematomas is good, but recurrence is more likely if underlying otitis externa is not treated and controlled. Once a hematoma has occurred in one ear, the other ear should be closely examined for otitis. Adequate treatment of otitis externa and close monitoring is essential to prevent pruritus and head shaking, which may lead to recurrent ear hematoma development.