Predisposing factors such as moisture act to increase the risk of development of otitis externa. In one study, the most common primary factors leading to otitis externa were: allergies, masses, endocrine disease, and autoimmune disease ( 6). Primary factors are those that directly induce inflammation within the external ear canal, such as hypersensitivity disorders. Otitis externa develops due to primary, predisposing, and perpetuating factors. The location and type of these lesions can help identify the primary factor in development of the chronic otitis externa. In any case of otitis externa, it is of utmost importance to perform a thorough dermatologic examination of the patient as approximately 76% of cases of chronic otitis externa will have other dermatologic lesions ( 1). In these cases surgery is often required ( 2). The vertical and horizontal canals can also mineralize and will be hard upon palpation. This leads to a more guarded prognosis as it is indicative of proliferative changes to the canal ( 1, 2). Patients may display pain on palpation of the ear canal if the canal is thickened, firm, and less pliable following chronic disease. If the infection has extended deeper into the middle or inner ear, causing an otitis media or otitis interna, neurological signs such as head tilt, vestibular disease, hearing loss, and pain when opening the mouth or swallowing might also be present ( 2). Some older studies also show that Labrador retrievers, miniature poodles, Afghans, Scottish terriers, fox terriers, Maltese, and German shepherds are also predisposed ( 1).Р”Вogs presenting with Pseudomonas otitis externa ( Figure 1) may exhibit one or a combination of the following clinical signs: head shaking, aural pruritus, malodor from the ear, erythema, alopecia, signs of self trauma to the pinnae and pre-auricular region, shyness around the head, discharge from the ear canal, aural hematoma, and ulceration of the external ear canal ( 1, 2). However, breed predispositions do exist and breeds such as cocker spaniels, Jura des Alpes, Brittany spaniels, golden retrievers, and West Highland white terriers are overrepresented ( 5). Previous reports indicate that younger individuals are more prone to development of otitis externa and these same studies document no gender predilection ( 5). Selecting antibiotics for treatment can be problematic due to the bacteriumРІР‚в„ўs resistance to many classes of antibiotics, and treatment is further complicated by the growing number of multidrug resistant strains ( 3, 4). It is not a normal inhabitant of the canine ear and when it leads to infection, it can be challenging to manage ( 1, 2). Pseudomonas aeruginosa is a ubiquitous Gram-negative bacillus found in soil, water, and decaying organic matter.

are among the most common bacterial pathogens in cases of infectious otitis externa, with Pseudomonas aeruginosa being the most common Gram-negative isolate ( 1, 2). Pseudomonas aeruginosa, Staphylococcus pseudintermedius, Escherichia coli, and Klebsiella spp. In many instances of otitis externa, secondary infection with bacteria or a fungus such as Malassezia pachydermatis, will be present. Otitis externa is defined as inflammation of the external ear canal consisting of the pinna, and the vertical and horizontal ear canals up to the level of the tympanum. In general practice, the percentage of canine cases presenting for otitis externa ranges from 7.5% to 16.5% ( 1). Otitis externa is a common complaint in veterinary medicine.

Dog ear drops otomax