Ear Infections - July 2020

This month’s article concerns ear infections, more often seen in dogs, and sometimes seen in cats. They range from mild to severe, acute to chronic, and causes for them can be varied. The fancy name veterinarians call it is otitis externa (referring to inflammation in the outer ear canal), although there can be ear infections that go deeper into the middle or inner parts of the ear. I will mostly discuss the outer ear infections, since this is what we mostly see at our clinic.

What are predisposing factors for this problem? The breed of the dog may influence whether or not it will have ear infections throughout its life. Cocker and Springer spaniels have a genetic condition which causes a gland in the skin of the ears to overgrow, causing those breeds to be more prone to otitis externa. Other breeds such as poodles or miniature poodles have excess hair in their canals which can predispose to ear infections. Other types of dogs such as spaniels, beagles, and basset hounds have long, hanging ear flaps that can aid in commonly developing this problem. English bulldogs, chows, and shar-peis often develop narrowed ear canals, leading to a higher chance to develop ear inflammation.

Signs of ear infection are as follows: scratching ears, shaking head, rubbing head, foul odor coming from ears, or waxy or creamy discharge seen in ear canals. Sometimes, there are no obvious outward signs, and it may be found on a yearly check-up or on a visit for another problem. If the infection is bad enough, a head tilt may be seen, and could mean the problem may be deeper than the outer canal. Other disorders that are associated with this problem are hot spots, aural hematomas (blood filling up in the ear flap after excessive scratching or head shaking), and middle ear infections (otitis media). Dogs with allergies can present with ear inflammation as well, which may be the only sign of the allergy.

When we diagnose an ear infection, we often need to find out what may be growing in the ear canal if there is a significant quantity of debris or discharge involved. Taking a sample from the ear and microscopically identifying the general type of bacteria or yeast helps in determining the treatment. This also aids in planning if the dog needs a long term maintenance plan if the dog is prone to this problem. The use of an otoscope helps to view the extent of inflammation in the ear canals, which help determine what type of anti-inflammatory medication is needed for therapy. Also, we need to see if the eardrum is intact in severe cases. Rarely, samples for a bacterial culture from the ear are needed for the determination of the best treatment.

Treatments for otitis externa are varied, depending on the severity of the problem. Some cases can be mild, and only anti-inflammatory drops are needed for that patient. In severe cases, a sedated deep ear flush is needed prior to actual therapy due to the extent of the discharge or debris in the ear canals. Cleaning the ears prior to the placement of ointment or drops to treat is very important because the wax, pus, or other debris can interfere with the medication, leading to a non-resolving infection. Ear cleaners or flush can be used to treat or prevent ear problems from occurring or getting worse. Some dogs may have to receive weekly or bi-weekly cleanings for maintenance. The amount of inflammation in the canals can cause mild irritation to severe pain in dogs with ear problems. Pain can determine what kind of medication is needed. Steroids are usually included in topical ointment for the ears, and are essential in resolving the inflammation in the ear or ears. Oral steroid medication is sometimes needed if the pain associated with the infection is moderate to severe, and if the ear canals are narrowed due to the inflammation. Antibiotics and antifungal medication are usually needed as well, depending on what is growing in the ear canal, and they are usually included in ear ointments. Oral antibiotics are NOT helpful in treating these infections if only the outer canal is involved. They can be used to treat middle or inner ear infections if needed in severe cases.

Ear infections in cats are not as common, the most likely reason for a kitten or younger cat to have this problem is due to ear mites. Dark brown or black discharge in a kitten’s ears means it is likely to have these little buggers. Diagnosis is simple, a swab is taken of the discharge and viewed under the microscope, and the mites are seen. Treatment is simple, either a liquid is placed directly in the ears, or Revolution (selamectin) is placed on the skin to eradicate the mites. Uncommonly, puppies can get ear mites as well. Himalayan or Persian cats may be predisposed, and older cats may develop growths (benign or cancerous) in their ear canals, leading to inflammation or infection.

Otitis externa is a very common condition seen at St. Francis Hospital for Animals. It can vary from being a mild issue or a chronic condition that often requires treatments. If you think your pet has this problem, give us a call, or ask about it at your next visit. Have a great summer!

Dr. Jaime Kozelka
St. Francis Hospital for Animals