Hey there, pet parents. Is your dog shaking their head, scratching at their ears, or holding their head to one side? Is there a bad smell coming from their ears? If so, you are likely dealing with one of the most common reasons that dogs see a vet: an Ear Infection, or Otitis Externa. Let's listen in on this very common problem.
What is Otitis Externa?
"Otitis" means inflammation of the ear, and "externa" means the external ear canal. So, otitis externa is an inflammation or infection of the external ear canal. This is the long, L-shaped tube that runs from the ear flap down to the eardrum.
The warm, dark, and moist environment of a dog's ear canal is the perfect breeding ground for bacteria and yeast. When the conditions are right, these organisms can overgrow and cause a painful infection.
Why Do Dogs Get Ear Infections? The Underlying Cause is Key.
This is the most important thing to understand about ear infections in dogs: the infection itself is almost always secondary to an underlying problem. A normal, healthy ear does not get infected. There is always an underlying reason that has changed the environment in the ear canal, allowing the bacteria or yeast to overgrow.
If you don't identify and manage the underlying cause, the ear infections will just keep coming back.
The most common underlying causes are:
- •Allergies: This is the #1 cause of recurrent ear infections. Both environmental allergies (atopy) and food allergies cause inflammation of the skin, including the skin that lines the ear canal. An inflamed ear is a perfect place for an infection to start. If your dog has recurrent ear infections, they have allergies until proven otherwise.
- 1Ear Mites: These are a common cause of ear infections in puppies and kittens.
- 2Anatomy: Dogs with long, floppy ears (like Basset Hounds and Cocker Spaniels) have poor air circulation, which traps moisture and creates a perfect environment for infection.
- 3Moisture: Dogs that swim a lot can get water trapped in their ears.
- 4Foreign Bodies: A piece of grass seed (a foxtail) can get stuck down in the ear canal and cause a nasty infection.
Spotting the Signs of an Ear Infection
- •Head Shaking.
- •Scratching or Pawing at the Ears.
- •A Bad Odor from the ears.
- •Redness and Swelling of the ear canal.
- •Discharge: The type of discharge can give a clue to the type of infection.
- •A brown, waxy discharge often points to a yeast infection.
- •A yellow or green, pus-like discharge often points to a bacterial infection.
- •Pain: The ear may be very painful to the touch.
- •A Head Tilt.
How Vets Diagnose an Ear Infection
- •Otoscopic Exam: Your vet will use an otoscope to look down into the ear canal to assess the level of inflammation and to check if the eardrum is intact.
- •Ear Cytology: This is the most important step! Your vet will take a swab of the discharge from the ear, stain it, and look at it under a microscope. This allows them to see exactly what they are dealing with: yeast, bacteria (rods or cocci), or both. This guides the choice of medication.
- •Culture and Sensitivity: If the infection is very severe or is not responding to treatment, a sample may be sent to the lab to culture the bacteria and see which antibiotics will be effective against it.
Treatment: Clean and Medicate
The treatment for a simple ear infection involves two main parts:
- •Cleaning the Ear: You can't just put medication into a dirty, debris-filled ear. The ear must be thoroughly cleaned to remove the gunk so the medication can get to the skin. Your vet will show you how to do this at home with a good ear cleaner.
- 1Medication: Based on the results of the cytology, your vet will prescribe a medicated ear drop. This is usually a combination product that contains an antibiotic, an antifungal, and a steroid to reduce inflammation. It's critical to use the medication for the full prescribed course, even if the ear looks better.
Your vet will want to recheck the ear after a few weeks to make sure the infection is completely gone.
The Key to Prevention
Remember, the key to preventing ear infections from coming back is to manage the underlying cause. If your dog has recurrent ear infections, you must work with your vet to diagnose and manage their underlying allergies. This is the only way to break the cycle of chronic ear problems.
Sources & Further Reading:
- •VCA Animal Hospitals - Ear Infections in Dogs (Otitis Externa)
- 1American Kennel Club - Dog Ear Infections: Symptoms, Causes, and Treatment