Ear infections, causing painful itchiness and irritation, are one of the most common problems afflicting dogs.

Although ear infections themselves are problematic, there are usually underlying causes of the inflammation of the external ear canals that become inflamed with bacterial or yeast overgrowth. With overgrowth of these organisms, inflammation of the ear canal increases causing swelling and narrowing the tubes. Inflammation also causes an increase in the wax production. External ear infections may progress to involve the middle and inner ear, leading to more serious signs of disease.

Chronic infection can permanently damage the ear canal and cause pain, neurologic signs, and deafness.


Symptoms may vary a great deal, depending on the severity of the ear infection. 

External ear infections may progress to involve the middle and inner ear, leading to more serious signs of disease:

  • External ear infection (otitis externa)
  • Painful, itchy sensitive ears
  • Cry or groan
  • Rubbing or scratching at ears
  • Shake their heads
  • Discharge, redness and odour from the ears
  • Scabs or crusting on the inside of the outer ear
  • Narrowing or even closing of the canals
  • Middle ear infection (otitis media)
  • Pain when opening mouth or reluctance to chew
  • Paralysis of the nerves in the face
  • Dry eye
  • Hearing loss
  • Abnormal pupil size
  • Inner ear infection (otitis interna)
  • Inability to keep balance, stand, or walk
  • Nausea or vomiting
  • Head tilting/shaking
  • Walking in circles


While bacteria are associated with ear infections, your veterinarian will determine the reason for your dog’s discomfort and if there is a certain disorder or disease that is the primary reason that the ear infections develop. 

These conditions include:

  • Foreign objects in the ear
  • Trauma to the body, such as head injuries
  • Ear mites increasing the likelihood of bacterial infection
  • A specific strain of yeast (Malassezia) that can lead to infection
  • A fungus (Aspergillus) linked to ear infections and inflammation
  • Conformation: Large floppy ears cover the canal, trap moisture and decrease airflow creating the perfect environment for bacteria and yeast
  • Allergies
  • Hypothyroidism can lead to a variety of different side-effects, including dry skin, bacterial infections and subsequent chronic ear infections
  • Polyps or tumours in the ear canal


Depending on the underlying cause, ear infections can resolve quickly or develop into a chronic condition. Your veterinarian will perform a complete physical exam of your dog, including the use of an otoscope to look down the ear canal. Other tests or procedures may be performed for an accurate diagnosis. 

Some additional tests your veterinarian may recommend include:

  • Cytology, which identifies if yeast, bacteria, or other microorganisms are present 
  • A culture to determine which type of bacteria is present
  • Blood tests to rule out hypothyroidism, autoimmune disease, or other underlying problems

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