Overview:

The L-shaped nature of a dog’s ear does not allow fluid to drain effectively from the openings. Thus, otitis externa can occur, which refers to the ear canal becoming inflamed. The lining of the ear canal may become inflamed which stops the flow of fluid and air, both in and out of the ear. otitis media (inflammation of the middle ear) can also develop in animals with otitis externa. This condition is similar to the problem found in children where pressure and pain is caused by the build up of fluid behind the eardrum. Both conditions are common in dogs, more so in breeds such as Cocker Spaniel and German Shepherd.

In younger pets, ear mites is the main cause of otitis externa. The parasites are associated with extreme itching and a brown discharge. Allergies (sensitivity to the environment or food) is a common underlying cause in adult dogs. Older dogs can develop tumors which can cause blockage of the ear canal as well as a secondary infection. Other causes of air flow blockage are small ear canals (common in Shar peis), foreign bodies or long and floppy ears such as those of a Basset hound. Hormonal problems and underlying skin conditions can also impact the development of otitis externa.

Signs and Symptoms:

The early symptoms of otitis externa are often mild, however they develop if left untreated or not treated effectively. Signs can include:

  • The underside of the ear may appear to red or thick under the ear or where hair is not present
  • Continuous scratching of their ears or shaking their head
  • A strong and unpleasant smell originating at the ears
  • A cauliflower-like appearance of the ear once the ear canal is blocked
  • The presence of a bacterial infection could cause a white thick discharge from the dog’s ears

The pain associated with the condition, especially when it develops into the middle ear, can cause personality or behavioral changes. This can include unwillingness to chew food or open their mouth wide and shying away from being petted on the head. They may also become less responsive as the blockage of the ear canal can cause sound to become muffled.

Diagnostics:

Otitis externa can usually be treated medically, except when there is a tumor or foreign body present or any other blockage which causes the ear canal to narrow. Firstly, your veterinarian will need to determine what is the cause of the condition. To do this, they can perform:

  • An otoscopic exam. This involves viewing the ear canal with a lighted scope. A sample may be taken from your pet’s ear to determine if yeast, mite or bacteria is a problem that your dog has.
  • Culture of discharge. This can help your veterinarian indicate the bacteria present and what antibiotics should be administered.
  • CT scan or X-rays. This is used to determine the severity of the case and whether or not the middle ear is effected. In the case where the ear canal has calcified and is no longer bendable, surgery may be necessary.
  • Blood test. The thyroid gland and blood chemistries will be examined for potential signs of systemic illness.
  • Allergies can be assessed through skin scrapes or allergy testin

Treatment:

If there is no blockage present, discharge and inflammation can be treated through medical management. Ear canals will we cleaned and flushed, sometimes the middle ear will also be drained to decrease the amount of fluid build-up. Organisms such as bacteria, mites or yeast will be killed through the appropriate treatment. To relieve the discomfort of the condition, your veterinarian may also provide pain medication. In the case of allergies, a diet change or shots may be required.

Removal of the ear canal is required when the pet has calcification, tumors, traumatic separation or other blockages. The surgery is known to be very complex and should only be performed by a qualified veterinarian.

Surgical Options:

  • Bulla osteotomy and total ear canal ablation
  • Vertical ear canal ablation
  • Lateral ear canal resection

Aftercare and Outcome:

After surgery, some restrictions are necessary to ensure recovery. These include:

  • Prevention of scratching of the ear incision which can be done with an E-collar (cone shaped).
  • Abnormal blink response may require that eye drops are administered for two weeks.
  • Oral pain medication.
  • Antibiotics are necessary in the presence of severe infection.
  • If the pet has stitches, they can be removed about 10-14 days post-operation.
  • If there are underlying disease, medical management may be required for life so that clinical signs do not recur.

Potential postoperative complications can include:

  • The inability to blink or abnormal blinking of the eye on the side of the surgery due to facial nerve damage. This occurs in a quarter to a half of cases. Damage is permanent in 10-15% of these cases.
  • Loss of balance can cause a head tilt.
  • In some cases, infection or secretory tissues remain and cause drainage to occur for month to years after surgery.

Hearing ability usually does not have a noticeable change as dogs with a case of severe otitis externa often have poor hearing ability prior to surgery.

Being prepared for ear problems in specific dog breeds, such as the Cocker spaniel, is essential. These dogs need to have their ears checked at least once or twice annually. If there is an infection present, it should be treated promptly to avoid development of further complications. Dogs who are prone to allergies should also be checked every year.

The underlying cause of otitis externa will determine the the prognosis of surgical treatment. Total ablation of the ear canal is a very successful procedure, however problems may recur if there is no control of underlying diseases or allergies. There is a much lower success rate for dogs who receive a lateral ear canal resection, especially when the ear canal is severely diseased.

Total ear canal ablation in a dog: