Otitis externa

Otitis refers to inflammation and/or infection of the ear and is one of the most common diseases of dogs and cats. The medical name for inflammation of the outer ear canal is 'otitis externa.' It is estimated that up to 20% of the dog population is affected by this disease.

Signs vary from:

  • Odour from the ears
  • Scratching or rubbing of ears and head
  • Discharge in the ears
  • Purulent disease of the outer ear
  • Redness or swelling of the ear flap or canal
  • Shaking of the head or tilting it to one side
  • Pain around the ears
  • Changes in behaviour such as depression or irritability
  • Blood sac (othaematoma) of the ear flap

It is less common in cats with the exception of those with a polyp in the ear canal or other inciting causes. Several different bacteria and fungi can cause otitis and the mite Demodex can cause otitis externa in dogs and cats.

The various causes of otitis externa may be classified as follows:


1.Primary factors- capable of causing otits in a normal ear.

  • Allergies- such as food allergies, contact allergies or hypersensitivities to airborne allergies.
  • Parasites- such as mites, ticks.
  • Foreign bodies – such as hair or grass awns.
  • Abnormalities in the production of keratin
  • Cancer or endocrine problems.

2. Predisposing factors- alter conditions within the ear, thereby making it more prone to infection and inflammation.

  • Pet’s anatomy- such as pendulous ears e.g. bassets, dachshunds & spaniels
  • Climate – e.g. humid environments
  • Pet’s behaviour- such as regular swimming which creates an excessively moist ear canal.

3. Perpetuating factors- allow for the disease to continue sometimes even if the primary cause has been removed.

  • Bacterial infections- e.g. E.coli, Pseudomonas, Staphylococcus
  • Yeast infections- e.g. Malassezia

As there are many potential causes of ear problems, one cannot just say it is a bacterial infection, dispense antibiotics, and assume it will go away. Often, more work is needed. Your veterinarian can use an otoscope to look down into the ear canal and determine the amount of inflammation present, if the ear drum is involved, and if there are any foreign bodies, tumours, or other potential causes of the problem. Swabs of the ear can be taken, smeared on a microscope slide, stained, and examined for bacteria, yeast, and mites. A thorough history and physical exam may help determine if this could be a hormonal, allergic, or hereditary problem. If these are suspected, further diagnostic testing would be needed. If a bacterial infection does not respond to the first antibiotic therapy, a culture and sensitivity may need to be performed to select a different antibiotic.

The key to healthy ears is to keep them clean. Check your dog’s ears weekly. A slight amount of waxy buildup may be present in normal ears. If your dog swims a lot, has pendulous ears, or a history of ear disease, routine cleaning (often once to three times per week) is recommended.
Remember, if your dog is showing severe discomfort, the ears have a bad smell, or the ear canals look very abnormal, do not delay in contacting your veterinarian.

Disclaimer: Zoetis takes no responsibility for any claims that may arise from information contained in this information sheet. Individual situations may vary from location to location and it is recommended that you consult your veterinarian before any management or treatment decisions are implemented.

Vrywaring: Zoetis neem geen verantwoordelikheid vir enige eise wat mag voortspruit uit inligting vervat in hierdie inligtingsdokument. Individuele situasies varieer van plek tot plek en dit word voorgestel dat u eers u veearts kontak alvorens enige bestuurs- of behandelingsbesluite geïmplementeer word.