Virginia Simpson and Chance

Ear Infections

by Elizabeth Gigis, DVM, West Chester Veterinary Center

The most common cause for a dog to start shaking his head and scratching his ears is an ear infection.  Most dogs have otitis externa, or an ear infection of the external ear canal.  Dogs have a vertical and horizontal ear canal, and both are very long.  In addition, many dogs have floppy ears, and this will trap dirt and moisture in the ear canal.  Another common history is that the dog has had a bath or gone swimming.  Water will sit in the ear canal and this will make the ear canal inflamed and infected.  Many breeds such as poodles will also have hair in the ears, when not plucked regularly, will trap dirt and moisture, leading to infection.  Other common causes are allergies, a foreign body in the ear (such as a plant) or ear mites.

All ear infections should be treated at the veterinarian’s office.  Most topical preparations available over the counter for ear infections are not effective.  If a dog’s ear drum is ruptured and some topical preparations are placed in the ear, then this can cause permanent damage to the inner ear and possibly even loss of hearing.  A veterinarian will be able to look into the dog’s ear with an otoscope, a device with a light and a long cone, visualizing changes in the ear canal and the ear drum.   Next, an ear cytology is usually performed to determine the cause of the ear infection.  This is done by taking ear exudate, smearing it on a slide, staining the slide, and examining it under a microscope.  That way, the cause of the infection can be appropriately treated.  The most common cause of an ear infection is bacterial, yeast or mixed bacterial/yeast infection.  Ear mites may also be visualized under the microscope.  

Complications of ear infections can include a ruptured ear drum, where you may see some loss of balance, a head tilt, or unusual eye motion back and forth.  These are all signs of vestibular disease.  Middle ear infections can also cause paralysis of the facial nerve, which manifests as drooping of the skin and loss of sensation on that side of the face.  Dogs that are very uncomfortable will scratch and shake excessively.  This may lead to breakage of the small blood vessels in the ear pinna (external ear flap).  The ear pinna will suddenly appear puffy and soft.    This is called and aural hematoma.  The veterinarian will treat this by draining the blood, placing a drain tube, and treating the ear infection. 

If your dog has chronic, recurrent ear infections, then he may have an underlying condition such as allergies or a hormonal imbalance.   Many dogs with food allergies will have ear infections as a primary symptom.  If your dog has chronic, year-round allergies, it may be pertinent to place him on a food trial.  Seasonal allergies or “atopic dermatitis” can also cause ear infections.  Commonly, dogs will get ear infections at a certain time of year.  There is allergy testing and treatment available for dogs.    Hormonal imbalances that contribute to chronic ear infections include hypothyroism and Cushing’s disease.  The thyroid controls the body’s metabolism.  Cushing’s disease is an over-production of steroid hormone.  Both of these diseases are diagnosed with blood testing and are treatable.  It will likely be very hard to control the ear infections if one of these underlying conditions is present, until the condition is controlled. 

Ear infections can sometimes be present for months to years.  It is important to obtain a diagnosis early, before chronic ear changes.  It is also important to have regular check-ups, use ear medications at home as prescribed, investigate all possible underlying conditions, and do weekly preventative maintenance.   With the combination of aggressive diagnostics and treatment, almost all ear infections can be successfully treated. 

Elizabeth Gigis, DVM
West Chester Veterinary Center
7330 Liberty Way, West Chester, OH 45069