Otitis externa is characterized by itchy ears, redness, local swelling, malodor and often a discharge. The nature of the odor and discharge depends on what the causative agent is.
The term otitis externa does not imply a cause; simply that the canal is inflammed. As mentioned above, foreign bodies such as grass awns, moisture (as from swimming in a lake), bacteria, yeast, and mites are all potential causes of inflammation and resulting infection or infestation, in the case of mites. Another potential cause is allergies, typically inhalant, causing red, swollen, and itchy ears.
If known, one would list the cause of the otitis before the term, such as: bacterial otitis externa or fungal otitis externa to be more specific.
Treatment of otitis externa depends on the cause. A good ear flushing is helpful for most cases of otitis externa. Antibiotics in the ear (and possibly by mouth as well) will help with bacterial problems and foreign body penetration. Antifungal and antiparasitic solutions will help with yeast and mites.
If your pet has a bad odor from the ears, is scratching or shaking the head constantly, please see your veterinarian as soon as possible to prevent further damage to the ears and ear drums.

