Ear Infections (Otitis Externa) in a Dog or Cat
Image by German photographer Elke Vogelsang
It’s time for a pop quiz! What is the number one reason for vet visits? If you said ear infections, you’re right!
According to Veterinary Pet Insurance, this was the number one reason for canine vet visits in 2015. It also made the top 10 for cats, at number seven. With just a little background knowledge on ear infections, you may be able to recognize this problem sooner and clear it up more quickly in your pets.
The ear canals in cats, and especially in dogs, are much longer than humans. It begins with a vertical ear canal, which makes a turn to become a horizontal ear canal, before reaching the tympanic membrane, or ear drum. Most ear infections are in these canals, on the outside of the ear drum. We call this otitis externa.
Identifying Otitis Externa (Ear Infection) in a Dog or Cat
The most commonly noticed signs are scratching the ears and shaking the head. However, some dogs and cats don’t give such clear clues. You may have to check the ears for discharge.
It’s normal to have a tiny amount of waxy or dirty debris caught in the folds of the ears, but if you see larger amounts of red-brown or creamy yellow discharge at the opening of the ear, this could be otitis.
Often times the discharge is malodorous and the skin of the affected ear(s) will be red.
Other signs that people sometimes notice are groaning and leaning into your hand more when scratching one ear over the other, discomfort, or the sound of liquid deep in the canals when you rub the ear.
Treating Ear Infections in a Dog or Cat
When you bring your pet in to see us, we will use an otoscope, with light and magnification, to examine the canals and tympanic membrane. By doing this, we will be able to make sure there is no foreign body present, such as plant material, and we will be able to check the health of the tympanic membrane.
If we suspect an infection, we will swab the discharge lining the canal and roll it onto a microscope slide. A microscopic exam of the discharge enables us to rule out ear mites, a less common cause of infection in house pets. Staining the slide will highlight any yeast and/or bacteria on the rest of the microscopic exam.
It is important to know what organisms are present in order to choose the best treatment and to monitor the resolution of the infection.
The Reasons for Repeated Ear Infections
Dogs and cats that get repeated infections often have an underlying condition predisposing them. Some dogs are simply born with very narrow ear canals (shar peis), long droopy ear flaps that cover the canals (retrievers and spaniels), or excessive hair in the canals (poodles), all of which trap moisture in the ears, setting up a perfect environment for the skin’s normal yeast or bacterial inhabitants to flourish and overgrow.
Endocrine diseases such as hypothyroidism and Cushing’s disease can be predisposing factors, too. These diseases are sometimes also accompanied by hair loss and other skin infections.
Younger cats may have a polyp, or tissue growth that predisposes them to infection. A less common cause in middle-aged to older pets can be tumors.
However, most commonly we see allergies as an underlying cause of otitis externa. These allergies may either be environmental allergies, called atopy, or food allergies.
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