Black & Tan Coonhound Club of GB

Ear Disease: a summary

Ear disease is a common problem in many breeds of dogs, affecting the variety of ear shapes and sizes. Unfortunately, ear disease can often be a recurring problem and this is usually because the underlying primary cause has not been detected and/or effectively treated. Want to learn more about canine ear anatomy and what happens when the ear is diseased? Dechra has a created touch-screen 4D interactive ear model: 

 

 

The causes of ear canal inflammation and infection (otitis externa) can be split into 3 categories: Primary, Predisposing and Perpetuating/Secondary

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Primary causes: These factors directly cause ear inflammation  

 

• Hypersensitivity/allergies: Atopic dermatitis (the most common, caused by allergies to environmental allergens like pollens or house dust mites), Adverse Food Reactions (food allergy or dietary intolerance), Contact hypersensitivity 

 

• Parasites: such as ear mites, scabies/’fox mange’ mites, Demodex canis mites, some species of fleas (rabbit fleas) and ticks 

 

• Foreign bodies such as grass seeds/awns, loose hair, sand, dirt, medication concretions (grooming powders-please don’t use these!) 

 

• Disorders of the ceruminous glands affecting ear wax production  

 

• Other less common disorders such as hypothyroidism, some autoimmune diseases, some inflammatory conditions, dermatophytosis/’ringworm’ 

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Predisposing factors: These increase the risk of development of ear disease but do not directly induce it: 

 

•  Conformation/shape of ears– Long, dangling ear flaps (pendulous pinnae)*, hairy ear canals/hirsutism, narrow ear canals 

 

• Excessive moisture – ‘Swimmer’s ear’, high humidity environment 

 

• Excessive cerumen (wax) 

 

• Ear canal obstruction with tumours and/or polyps 

 

• Generalised disease affecting ear health such immune suppression, viral disease, some cancers or metabolic disease  
   

*Especially with breeds such as the Black and Tan Coonhound with large, floppy ears, it is important to note that ear shape is considered a predisposing factor and NOT a primary cause of ear disease, therefore not all Black and Tan Coonhounds will have ear disease, but they are all predisposed because of the Scent hound ear shape and size. 

 

Perpetuating/Secondary Causes: These factors prevent resolution of the disease 

 

• Progressive changes to the ear canal tissues (from longstanding/chronic inflammation and recurrent infections), which affects normal wax production, often with swelling and blockage of the ear canal. Eventually, this can lead, in some cases, to irreversible changes, such as scarring, middle ear disease, and bone and cartilage involvement.   

 

 

• Secondary infections are very, very common, and will contribute to the progressive changes mentioned above. Common microorganisms seen are yeast organisms (commonly Malassezia pachydermatis and/or Candida sp.) and/or bacteria (commonly Staphylococcus pseudintermedius, Streptococcus sp., Pseudomonas sp., Proteus sp., Escherichia coli).

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Unfortunately, in some longstanding ear disease cases, with irreversible changes in the ear canal anatomy, major surgical intervention can be the only long-term solution. It is therefore imperative to identify the primary underlying cause of the ear disease along with appropriate control of any secondary infections and inflammation.  

 

Some cases may require referral to a veterinary dermatology specialist who may have specialized equipment such as a video-otoscope to accurately assess, clean/flush and treat the ear canal. Allergy testing may also be advised, along with a dietary trial to rule in/rule out a dietary component to the disease. Assessment of ear infections is done with using microscopy/cytology and sometimes followed with bacterial culture if antibiotic-resistant strain of bacteria is suspected (Pseudomonas sp.).