By University of Illinois College of Veterinary Medicine
Head-shaking, scratching at the ears and a foul smell are common signs that an ear infection is brewing.
Amelia White, a veterinary dermatology resident at the University of Illinois College of Veterinary Medicine in Urbana, said ear infections are usually caused by an underlying problem, so it is important to treat both the ear infection and the primary cause to completely resolve the problem.
"Owners often bring the pet in after noticing odor and discharge in the pet's ears," White said. "Most of the time, these bacterial and yeast infections of the ears turn out to be secondary to a primary cause, but it can take time and several tests to arrive at a diagnosis."
Some of the most common primary reasons for external ear infections are food and environmental allergies, external parasites such as mites and ticks, foreign bodies, cancer, a problem of the endocrine system such as hypothyroidism and autoimmune diseases.
Owners might be tempted to clean the gunk out of their pets' ears themselves, prior to visiting the veterinarian, but White recommends against this. Cleaning could cause further damage to the ears if owners have not been instructed on proper ear-cleaning techniques.
"Never use cotton swabs, which can cause impaction of wax deep in the canal. They can cause trauma to the ear canal or eardrum and can break off within the canal," White said.
Another reason not to clean the infected ears is to allow the veterinarian to see the disease in its most natural state. After the veterinarian determines the cause of the infection, the owner can be shown the appropriate follow-up care.
The veterinarian will begin by examining the ear canal using a hand-held otoscope to see if there are any abnormalities with the ear canal tissue or eardrum. If debris is present, the veterinarian will obtain a sample for microscopic examination for parasites, bacteria, yeast and inflammatory cells.
Depending on the severity and frequency of the infections, a veterinarian may recommend more advanced diagnostic techniques, such as deep ear flushing, video otoscopy, radiographs, CT scan or even MRI. Referral to a specialist is recommended in chronic or unusual cases of ear infection.
White said identification and treatment of the primary cause of infection is the most important aspect of therapy, because if the primary cause is not addressed, the ear infection will return rapidly or fail to respond to therapy.
Typical treatment includes ear cleaners to remove debris, topical ear medications to treat for parasites and/or infection — and occasionally systemic antimicrobials or anti-inflammatory medications. These are all easy to administer at home.
"If left untreated, an ear infection may spread to the middle or inner ear, which can lead to neurologic problems and deafness," White said.
So how can an owner prevent ear infections in their pet? White said normal dogs should not develop ear infections, but some predisposing factors can lead to ear infections in normal pets.
Examples include frequent swimming or bathing, narrow ear canals, long floppy ears, traumatic plucking of hair from the ear canals and overly aggressive cleaning of the ears. Unless a pet is participating in an activity that may predispose it to infection, such as daily swimming, then regular ear cleaning is not recommended in normal pets.
"I also recommend not to pluck the hair from the ear canals of dogs during grooming, as this creates inflammation within the canal that often leads to secondary infections," White said. "If you are concerned about the routine care plan for the ears of your pet, I always recommend discussing this with your veterinarian in order to develop the best health plan for the pet."
An archive of pet columns from the UI College of Veterinary Medicine is available at http://vetmed.illinois.edu/petcolumns/. Requests for reprints of this article may be directed to Chris Beuoy, email@example.com.