Canine Otitis externa – Treatment and complications
Otitis externa is a very common aliment in dogs caused by an inflammatory process of the external ear canal, resulting in either an acute or chronic nature.
Chronic cases are due to changes in the external ear in response to long periods of inflammation which increases humidity and pH of the external ear, risking a higher predisposition to infection. The most common pathogens found in the dog’s ear canal are Staphylococcus spp. and Malassezia spp. Some pathogens produce a biofilm that leads to persistent infection despite adequate therapy.
If acute and without complications, otitis externa can be easily treated. Chronic cases are the real challenge, where client education and follow ups have a central role in the prevention of the end-stage of the disease. There are many factors that play a role in this disease, some are predisposing factors like excessive hair inside the ear canal. Others are perpetuating factors, for example microorganisms that are not the cause of the otitis but exacerbate the inflammatory response, creating a vicious circle. The latter can justify treatment failure for most cases.
The complete treatment of otitis externa consists of treating the infection and inflammation and identify the underlying factors that contributed to the development of the otitis externa in the first place.
Cytological analysis is extremely important for decision making and cleaning the ears before any topical therapy is mandatory in order for the medication to be effective. Most dogs will benefit from anti-inflammatory therapy and glucocorticoids. In specific cases, it can help break the biofilm but this cannot be used for prolonged periods. Recurrence of the disease, despite documented resolution, indicates the need of analyzing all possible underlying primary causes and predisposing and perpetuating factors.
There are very few measures to prevent otitis externa, detection of mild and early cases is essential to prevent further development of the disease. These measures combined with client education and frequent follow-ups can help prevent the progression into chronic otitis, hearing loss, otitis media and end-stage disease.
Bajwa, J. (2019). Canine otitis externa – Treatment and complications. The Canadian Veterinary Journal. La Revue Veterinaire Canadienne, 60(1), 97–99.
