Aetiology of canine otitis externa: a retrospective study of 100 cases

Abstract

The objective of this retrospective study was to investigate in 100 dogs with otitis externa (OE) the possible associations between signalment, history, clinical and laboratory findings and the various primary, secondary and perpetuating causative factors of ear canal inflammation. The age of the dogs ranged from 3 months to 14 years (median: 4.75 years) and they included 45 males and 55 females. Cocker spaniels, Jura des Alpes and Brittany spaniels were significantly overrepresented among dogs with OE when compared to the hospital canine population. In the majority of the cases, OE was chronic-recurrent (63%) or bilateral (93%). Allergic dermatitis (43/100 dogs), grass awns (12/100) and otoacariasis (7/100) were the most common primary causative factors; no primary factor could be incriminated in 32 cases and more than one was found in three dogs. Malassezia spp. (66/100 dogs), cocci (38/100) and rods (22/100) were the secondary causative factors, while ear canal stenosis (38/100) and tympanic membrane perforation-otitis media (25/100) were the most important perpetuating factors. Atopic dermatitis and adverse food reactions-associated OE was more common in females and dogs with a history of pruritic skin disease, while grass awn-induced OE occurred in cocker spaniels and acute cases. Tympanic membrane perforation was less frequent in atopic dermatitis and adverse food reactions-associated OE, but more common when otoscopic and ear canal cytological examination revealed the presence of grass awns and rods, respectively. Finally, cocci overgrowth was positively associated with ear canal stenosis.

Perfil clínico e microbiológico de cães com e sem otoacaríase

“…Ainda, o exudato pode mudar de aparência e se tornar purulento, em decorrência de infecção secundária fúngica e/ou bacteriana, deixando o ambiente do conduto impróprio para a sobrevivência dos ácaros. Saridomichelakis et al (2007) demonstraram resultados próximos aos relatados quando avaliaram 100 cães com otite externa de diferentes etiologias. Dentre estes, sete animais apresentavam otoacaríase com secreção otológica associada, sendo: três (42,9%) cães com secreção escura semilíquida, um (14,3%) com secreção amarelada semilíquida, um (14,3%) com secreção ceruminosa, um (14,3%) com secreção escura mais endurecida e um (14,3%) sem secreção.…”

“…Os fatores causadores da otopatia são classificados como: predisponentes, primários, secundários e perpetuantes (Saridomichelakis et al, 2007).…”

“…Esses fatores primários podem iniciar uma inflamação e esta ser intensificada pelos fatores secundários, as infecções bacterianas e fúngicas. Ainda de acordo com a cronicidade das alterações, podem ocorrer os fatores perpetuantes, que são mudanças permanentes do conduto auditivo, membrana timpânica e orelha média (Gotthelf, 2007;Saridomichelakis et al, 2007;Oliveira et al, 2012).…”

Treatment of Canine Otitis Externa Using Video Otoscopy

“…The concavity was observed even more clearly by rotating the video otoscope's light source 180 degrees. In contrast, conventional procedures performed with a handheld otoscope do not permit * CORRESPONDENCE TO: USUI, R., Usui Animal Hospital, [4][5] Midorino, Utsunomiya, Tochigi 321-0136, Japan. e-mail: rei@u-a-h.com confirmation of this concavity due to their inability to remove hair and debris.…”

“…Numerous studies have described methods to treat otitis externa, but the condition is prone to relapse and chronicity [1,3,5]. The most common method of treatment involves cleansing the ear canal by applying a cleansing solution or ceruminolytic solution into the ear canal and manually massaging the outer ear, followed by application of ear drops.…”