Veterinarian column: Otitis externa in dogs

by Alice's Dog & Cat獣医師

Alice’Dog&Cat Veterinarian Column

Do you have problems such as having your dog's ears become dirty when trimming or having recurring otitis externa? Otitis externa in dogs is not just a disease of the ears, but is often associated with atopic dermatitis or allergies. It is necessary to fully understand the cause of otitis externa and provide appropriate treatment. In this article, we will explain in detail about otitis externa in dogs.

◎ Causes of otitis externa

Otitis externa is often caused by a combination of factors.

Main cause: This alone causes otitis externa.


・Parasite (ear mite)

・Foreign matter


・Others (seborrhea, endocrine disease, secretory gland abnormalities)

Secondary causes: Occurs in combination with the main cause and other secondary causes.



- Improper ear cleaning

Exacerbating factors: Factors that worsen otitis externa

・Narrowing of the auditory canal

・Epithelial migration disorder

・Changes in earwax lines

・Otitis media

Predisposing factors: Factors that increase the risk of developing otitis externa

・Ear morphological problems (drop ears, narrow auditory canal)

・Environment (high temperature and humidity)

・Closed lesions

◎ Examination for otitis externa

・Observation of the external auditory canal using an otoscope

・Earwax examination: Confirmation of growth of bacteria and Malassezia. If bacterial growth is observed, drug susceptibility testing. Presence or absence of ear mites.

・Blood test: Endocrine disease, allergy test.

・Video otoscope examination, CT/MRI examination: Performed when severe otitis externa or otitis media is suspected.

◎ Treatment of otitis externa

・Cleaning the external auditory canal

・Ear drops: There are different types of ear drops, such as liquids, creams, etc., different materials, durations, anti-inflammatory effects, and antibacterial agents. )

・Oral medications: Steroids (taken orally if swelling or inflammation is severe) Antibacterial drugs (if bacterial growth is observed, appropriate antibiotics are taken orally based on the susceptibility test results) Antifungal drugs (Malassezia (Administer orally if the proliferation is severe.)

・Surgery: If medical treatment is difficult, surgery such as auditory canal resection may be performed.

◎ Prevention of otitis externa

If there is an allergy or endocrine disorder that is the main cause, be sure to treat the underlying disease. Also, have your dog's ear canal checked at a veterinary clinic once every 1-2 months .

The treatment cost for otitis externa is around 3,000 yen for cleaning, ear drops, and examination, but the cost may be higher because drug sensitivity tests and blood tests may be performed if necessary. However, if the underlying disease is not treated, it may recur or become chronic, so this test is necessary if an underlying disease is suspected. When otitis externa becomes severe, it takes time to treat it. If you notice dirt or odor in your pet's ears, take him to a veterinarian as soon as possible and receive thorough treatment until the dog's ears are completely cured.