Ear Infections Caused by Yeast in Dogs

The ear flap and inner structures of a dog

Yeast overgrowth can have many underlying causes but allergy is particularly common as is the dog’s ear getting wet. Add to that, the fact that yeast loves dark and most places and you’ll see that the dog ear almost screams for yeast to set up shop.

For dogs that have recurrent issues with yeast, regular (weekly) ear washes with a veterinary product that acidifies and dries the canal is called for. 

Yeast infections are the most common type of ear infection in dogs. The yeast organisms are fungi called Malassezia and they are normal (in small quantities) on the skin and in the ears. When the ear becomes inflamed and the environment changes, the yeast take advantage, overgrow and results in the glands of the ears producing a brown greasy ear discharge. 

It is especially itchy and somewhat smelly. It isn’t long before the pet is seen scratching at his ears, shaking his head, or holding one ear slightly dropped. Discharge and odor may be noticeable to the owner.

Complications of Ear Infections

Aural Hematoma
When a dog with uncomfortable ears shakes and scratches vigorously, a blood vessel in the earflap may rupture. This leads to bleeding into the tissues of the ear flap. The usual recommendation is to have the blood clots removed and the ear flapped sutured together under anesthesia. 

Proliferative Ear Canal Change and Middle Ear Infection
A routine ear infection is uncomfortable enough but if the infection persists, it can become an even bigger problem. The infection can lead to proliferation and scarring in the canal which makes the infection especially difficult (and potentially impossible) to clear up. Yeast organisms are joined by resistant bacteria and the infection becomes even more difficult to address.

Over time, the ear canal may mineralize and the middle ear may come to be involved, leading to nerve damage. Affected animals may have a head tilt, a lack of balance, and unusual back-and-forth eye movements (called “nystagmus.”) These symptoms are called vestibular signs”and are a complication of middle ear infection. 

Severe and chronic cases may result in permanent damage, which becomes another issues entirely. The good news is, yeast infections are easily treated. But because yeast takes a while to grow, it also takes a while – sometimes several weeks to kill.

It may require surgical intervention to remove the vertical portion of the ear canal (lateral ear resection)  or even remove and seal the ear canal (ear canal ablation). It is important to control ear infections before they reach this stage if at all possible.

Don’t stop treatments until your veterinarian rechecks the ear and looks at the discharge under a microscope and tells you that the infection has resolved.

Treatment 

Yeast under a microscope

Level One: The Simple Ear Infections
Most ear infections are cleared up simply with professional cleaning followed by medication at home. If only mild debris is present in the ear canals, simple disinfection and washing of the ear is adequate; however, in many cases, a full ear flush is needed to even examine the eardrum. For patient comfort, we recommend sedation for this procedure as the ears are sore and the instruments can be damaging if the pet jumps at the wrong time. A sample of ear discharge is commonly examined under the microscope so as to assist in selecting medications for home use. After a 2-3 weeks home treatment, the ear canals are rechecked to be sure the infection is gone. In most cases this completes treatment but for stubborn cases, we must proceed to the next step.

Level Two: On-Going Ear Infections
Some dogs have chronic ear problems (the infection is not controlled by general medication or returns when general medication is discontinued). In these cases, the ear discharge should be cultured so that the precise organism can be pinpointed and treated specifically. Regular treatment at home with disinfecting ear washes should become part of the pet’s grooming routine.

Further testing may be in order to determine why the infection continues to recur. Allergy is the most common reason for recurrent ear problems but hormone imbalances can also be underlying causes.

Level Three: The End-Stage Ear
Some ear infections simply cannot be controlled with the above steps. These cases have transcended medical management and must proceed to surgical management. What this entails will depend on the state of the ear canal. Your veterinarian will make recommendations accordingly.

About the author: Hilary Granson

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