Though ear infections are incredibly common in our canine patients, I do not encounter otitis interna (inner ear infection) much at all in my practice. The dog’s ear is designed to try and prevent infections from spreading internally, to protect the central nervous system. When a patient of mine does develop an internal ear infection, signs tend to be quite debilitating and can go on for some time.
Usually, it is those dogs who have been struggling with chronic ear issues for a long time that go on to develop inner ear infections.
What are inner ear infections in dogs?
An inner ear infection is when bacteria or fungi proliferate within the inner ear, causing a range of symptoms in the dog. For some dogs, they are triggered by polyps or foreign bodies (like grass awns) within the ears, and for others they are associated with atopic skin disease and chronic external ear infections.
‘Otitis Interna’ refers to inflammation within the inner ear and this is most often caused by an infection in our furry friends. The most common bacteria involved are Staphylococcus, Streptococcus and Pseudomonas1.
Impact to a dog’s quality of life
There is no doubt that an inner ear infection has a hugely negative impact on a dog’s quality of life and can make them absolutely miserable. They can develop a range of symptoms and are often in a great deal of pain.
Top symptoms of inner ear infections in dogs
- A red, inflamed, waxy and smelly outer ear
- Head shaking and head tilt due to inflammation of the VIII cranial nerve.
- Ear scratching
- Dizziness and loss of balance
- Nausea and vomiting
- Trouble eating, due to jaw pain
- Eye symptoms. This can include a reduced ability to blink, discharge of the eye and a droopy eyelid due to nerve inflammation.
- Horner’s Syndrome
- Reduced ability to hear
- Nystagmus (eye flickering from one side to the other)
What happens if inner ear infections are not treated fast enough?
Yes, inner ear infections are very concerning and cause our dogs a great deal of distress. The sooner they can be addressed, the more chance of a good outcome. If left untreated, signs can progress and dogs may develop worsening issues with their balance and food refusal due to nausea and oral pain. They may also become dehydrated, if vomiting and not wanting to eat.
Over time, the ear canal can become thickened and swollen, making it much harder for the medication to work.
Treatments & prognosis of inner ear infections
How we treat the inner ear infection depends on how long it has been present, the cause of the otitis and what sort of infection it is. It also depends on if this is the first occurence, or one episode of many.
For acute episodes when the dog is suddenly very unwell and off balance, we can manage them by admitting them to the hospital on an IV fluid drip with medication including anti-nausea drugs, anti inflammatories, pain relief and antibiotics.
Oftentimes the dog is put under a general anesthetic so we can swab the canal to determine which bugs are present, flush the ear removing any wax or debris and instil local medication.
When antibiotics are issued, this is usually for a long course of at least 6 weeks, to ensure the infection is completely eliminated.
For more ongoing cases that are refractory to treatment, surgical intervention may be required. Which surgery is best will depend on factors including how long the dog has had signs and which procedure is preferred by the surgeon. Some options include curettage of the tympanic cavity or a ventral bulla osteotomy2.
The prognosis is variable and depends on the bacteria involved as well as how long the issue has been ongoing for. Cases treated early on have the best prognosis. Severe and ongoing cases can lead to permanent neurological deficits and deafness.
What to do to help a dog with inner ear infections
If you suspect your dog has an ear infection, there are some things that can help while you await your vet appointment.
If your dog is scratching at their ear, protect it by using a buster collar.
Any wax, debris or pus can be cleared out of the ear with an ear cleaner and cotton wool and this can be done daily while the ear is infected. If the eardrum is ruptured, your vet may well advise you hold off on any cleaning.
Try to take your dog’s mind off the discomfort with things like food puzzles, training sessions and exercise.
Which dogs are more prone to inner ear infections?
There are certain factors that make a dog more likely to develop an ear infection and this would include:
- Underlying allergic skin disease
- The presence of ear polyps
- Floppy and hairy ears. This is because the ear canals are not well ventilated, so the conditions within the canals are moist and warm; ideal for bacterial proliferations.
- Lifestyle factors including regular swimming
With ear infections, we want to treat them as soon as we possibly can, to prevent them from spreading inwards and to ensure they do not grumble along.
Any allergic skin disease should be well managed with a combination of allergen avoidance and medication as needed.
Those with floppy ears may need regular ear cleaning. How often this is needed depends on the dog, but usually 1-2 times a month is sufficient.
After water gets in the ears (e.g. after swimming or grooming), they should be dried out thoroughly using cotton wool.
Your visit at the vet
Each visit will be different and should be tailored to the patient.
Questions your vet will ask you
Your vet will want to know if your dog is prone to ear issues and/or skin disease and will ask about any previous ear drops that have been used. They’ll also ask about the signs your dog has been experiencing and how they have impacted on their day to day life. Your vet will also enquire about any lifestyle risk factors, such as regular swimming.
What your vet may do during the consult
Your vet should perform a thorough physical exam which will include a neurological exam and an otoscopic exam of the ears.
However, if your dog is in too much pain to allow their ears to be examined, this may be done under sedation or anesthetic at a later date. Your vet is also likely to swab any infection at this time
Diagnosis & cost of diagnosis
Diagnosis is largely based on the symptoms your dog is showing and the appearance of their ear.
As well as examining the ears and taking a swab for culture and sensitivity ($200-300), your vet may suggest x-rays ($350-600) or a CT scan ($1,000-1,500) to examine the round bones of the ears and assess the extent of damage3.
- Otitis Interna in Dogs, Vetlexicon
- Harry W Booth Jr, Surgical management of otitis media and otitis interna
- Otitis media and interna in dogs, MSD Manual
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