Tympanic Membrane Rupture and Middle Ear Infection in Dogs

What are the tympanic membrane and middle ear?

The tympanic membrane, or eardrum, is a thin membrane that separates the outer ear canal from the middle ear. The middle ear contains three tiny bones that transmit sound. The eustachian tubes are also located in the middle ear and connect it to the nasopharynx—the area behind the nose.

What causes an eardrum to rupture?

An eardrum may rupture due to trauma, infection, exposure to toxins, sudden severe changes in atmospheric pressure, very loud noises, or contact with a foreign object.

What is a middle ear infection?

If the eardrum tears or is punctured, bacteria and fungi from the outer ear canal may enter the sensitive middle ear, resulting in a middle ear infection (otitis media). A middle ear infection can also occur due to a polyp or mass (benign or malignant tumor). Rarely, an infection in the nose or throat can move up the eustachian tube into the middle ear.

What are the signs of a ruptured eardrum or middle ear infection?

Middle ear infections are often accompanied by inner ear infections and disruptions in balance and equilibrium. Signs that your dog may have a ruptured eardrum or middle ear infection include:

• Discharge from the ear (often thick and pus-like or bloody)
• Sudden hearing loss
• A red or inflamed ear canal
• Pain when touching the ear
• A head tilt
• Stumbling

Facial nerve paralysis may occur in some cases. Signs include:

• Nystagmus (darting of the eyes back and forth)
• Drooping of one side of the face and mouth
• Inability to blink 
• Completely closed eyelid

How are ruptured eardrums and middle ear infections diagnosed?

Ear examination: A thorough ear examination by your veterinarian, sometimes requiring sedation or anesthesia, is necessary to diagnose a ruptured eardrum. The ear canal may need to be flushed with warm saline so your veterinarian can see the eardrum clearly. 

Additional tests may help identify a rupture. Your veterinarian may look for tiny air bubbles that form deep in the ear canal when your dog breathes. Another test involves placing a special dye, fluorescein, into the ear canal. If the dye passes through the middle ear and exits through the nose, the eardrum is ruptured.

Imaging: Skull radiographs (X-rays) help determine the severity of a middle ear infection. Your veterinarian may recommend CT or MRI scans to provide more detailed information.

Fluid sampling: A myringotomy is usually performed in cases of middle ear infections. A myringotomy involves obtaining a sterile sample of the fluid within the middle ear for culture and analysis. It is usually performed under sedation or anesthesia as part of the thorough ear examination. Your veterinarian will discuss whether this diagnostic test is necessary for your dog.

How are these conditions treated?

A thorough ear flushing, usually under sedation or anesthesia, is required in most cases. Your veterinarian will use appropriate medications and sometimes water-based flushing solutions (most often TrizEDTA). Depending on your dog’s condition, your veterinarian may prescribe:

• Topical antibiotics may be prescribed based on your dog's specific condition. 
• Oral antibiotics may be used (e.g., amoxicillin/clavulanate, enrofloxacin, cefpodoxime, or marbofloxacin).
• Antifungal medications may be used (e.g., ketoconazole or itraconazole).
• Systemic corticosteroids, typically prednisone, may be beneficial in dogs with severe inflammation and pain.

Surgery is sometimes needed and is typically reserved for patients thought to have severe, irreversible changes of the outer ear occurring at the same time as a middle ear infection. If surgery is recommended for your dog, your veterinarian will discuss the reasons why, the risks involved, and the expected outcomes with you.

What is the prognosis?

Many dogs heal without significant complications. Most ruptured eardrums heal without surgery within three to five weeks. Middle ear infections often require oral antibiotics or antifungal medications for four to six weeks. Most dogs need frequent recheck examinations and follow-up care to ensure the infection is resolving, and the eardrum is healing properly. Follow your veterinarian’s instructions to help prevent serious complications or prolonged healing.

In severe cases with nerve damage, there may be hearing loss and permanent changes in the face, lips, and eyes. Your veterinarian will give you a more specific prognosis based on your dog’s specific condition.