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Chronic Otitis in Dogs: What You Need to Know

Chronic Otitis  in Dogs: What You Need to Know | BetterVet


Ear infections can be miserable for both dogs and humans. Chronic ear infections in dogs are particularly nasty and can take a lot of time and effort to treat effectively.

You might have heard your veterinarian refer to your dog’s chronic ear infection as “Chronic otitis” – but what does this mean? What causes these long-standing, difficult-to-treat infections? Let’s have a look.  


What Is Chronic Otitis in Dogs?

“Chronic Otitis” is the technical term for a long-standing ear infection. 

  • “Otitis” is inflammation of the ear
  • “Chronic” means that the illness has been present for a while – usually a month or more. 

What Are the Symptoms of Chronic Otitis in Dogs?

Dogs with a chronic ear infection may have many different symptoms, including:

  • Redness around the outside of the ear
  • Swelling around the base of the ear
  • Itchiness around the ear, which may cause them to scratch the ear, or rub it along the floor
  • Pain when the ear is touched
  • Thick, sticky fluid coming from the ear.

If it is left untreated, chronic otitis is one of the most common causes of a middle or inner ear infection in dogs. The symptoms of an inner ear infection include:

  • Tilting the head to one side
  • Loss of balance
  • Falling to one side
  • Eyes flickering (“nystagmus”)

What Causes Chronic Otitis in Dogs? 

Chronic otitis is usually caused by a bacterial infection in the ear. These infections are not usually contagious (they cannot pass between dogs), but instead are caused by an overgrowth of the bacteria and yeasts that are naturally found within the ear. This overgrowth happens as a result of some sort of problem within the ear. 

Several different kinds of problems can cause chronic ear infections in dogs, including:

  • Seasonal allergies
  • Water in the ear, usually from bathing or regular swimming
  • A hormone problem, such as an underactive thyroid
  • Ear mites
  • A foreign body in the ear canal, such as a grass awn.

It is important that your veterinarian determines the exact cause of your dog’s ear infection, as the treatment for each of these conditions may be different. 


How Can We Diagnose the Cause of Chronic Otitis in Dogs? 

There are several different tests that your veterinarian may recommend to work out what is causing your dog’s ear infections. These include:

  • Taking some material from the ear and examining it under a microscope to look for signs of ear mites, and to try and see which types of bacteria are present.  
  • Taking a swab from the ear to see exactly which bacteria or yeasts are causing the problem, and to make sure that your dog is on the correct antibiotics.
  • Blood tests, including a thyroid panel, to check for underlying illnesses that might be weakening your dog’s immune system. 
  • Examining the ear under sedation or anesthesia to see if there are any signs of a foreign body within the ear, and to allow them to flush the discharge out of the ear. 
  • Allergy testing, which may include a special blood test or intradermal tests

Your vet will consider your dog’s age, breed, and any other symptoms that they may be showing, and recommend the tests that they think are appropriate. 

If your vet thinks that your dog may have an inner ear infection, then they may recommend referral to a specialist, as advanced imaging (MRI or CT scan) is needed to accurately diagnose the issues. Alternatively, x-rays can sometimes be used if advanced imaging is not available. 


How Can We Treat Chronic Otitis in Dogs?  

There are two parts to treating chronic ear infections in dogs – treating the infection itself and treating the underlying cause. 


Treating the Infection

It is important to make sure that your dog is receiving the correct antibiotics for their infection, which is why your veterinarian may take a swab to guide their treatment. 


Ear drops

The most effective way to treat an ear infection is with ear drops. They are better than tablet antibiotics for several reasons:

  • Ear drops go straight to where they are needed, rather than traveling all around the body as they do when they are taken as tablets. 
  • Tablet antibiotics only treat bacteria found in or on the skin that lines the ear canals (the passage within the ear), whereas ear drops can treat the bacteria hiding in the middle of the ear canal, too. 
  • Drops give a much higher concentration of antibiotics in the ear than tablets. 


When Are Ear Drops Not Suitable?

There are some situations where ear drops are not appropriate. For example, if your dog has a burst eardrum, then the drops may pass through the outer ear to the middle ear and inner ear. Certain drugs in ear drops can affect the inner ear, leading to issues with hearing and balance. In these cases, your veterinarian will discuss the options with you. 

Ear drops are less effective if there is discharge present in the ear canal as this can protect the bacteria from the antibiotics in the drops. Sometimes this can be treated by using an ear cleaning liquid before applying the ear drops. However, in more severe cases, dogs may need a general anesthetic to allow the vet to clean out the ear canal with sterile saline to remove the buildup. Sometimes this only needs to be done once, but occasionally it will need to be repeated several times. 

Middle and inner ear infections in dogs can be difficult to treat, and may require surgery and long courses of antibiotic tablets to fully heal. 


Treating the Underlying Cause

As well as treating the infection, it is important to also treat the underlying cause – the reason that your dog has developed this infection in the first place. 

The treatment will depend on what the underlying cause is. This might be as simple as removing a grass seed from the ear or might mean life-long treatment for skin allergies. Your veterinarian will discuss your dog’s particular condition with you, and come up with a treatment plan. 



Ear infections are itchy and painful for your dog and can be difficult and expensive to treat. If you suspect that your dog has an ear infection, then do not delay – book an appointment with a veterinarian today to get them checked out. 

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