Introduction

Otitis externa is one of the most common and multifactorial disorders accounting for upto 10-20% of consultations in canine practice (Scott et al., 2001). It is defined as an acute or chronic inflammation of the epithelium of the external ear canal which may also involve the pinna and it results from a combination of dynamic changes affecting the anatomical, physiological and microbiological status of the external ear canal. The most recent classification for the aetiology of otitis externa has been proposed by Griffin (2010). In this system the aetiology of otitis externa can be divided into primary and secondary causes which directly cause inflammation in the ear and perpetuating or predisposing factors that prevent resolution of the disease and lead to recurrence if they are not dealt with adequately. The practicing veterinarian may get frustrated as the relapses are very common due to treatment failures and if left untreated the consequences may be very serious (Kumar et al., 2002). This study presents the prevalence of otitis externa in in relation with age, breed and gender.

Materials and Methods

All the clinical cases of canines reported at the college veterinary hospital, Tirupati during the period from December 2013 to July 2014 formed the subject to the present study. The prevalence was calculated taking into account of the otitis externa cases detected out of the total dogs screened. Dogs with otitis externa were further analysed in relation to age, breed and sex.

Results and Discussion

During the period under study, screening of 610 cases presented at College veterinary hospital, Tirupati revealed that otitis externa accounted for 42 dogs (57 ears) and thus, out of all maladies of dogs the overall prevalence of otitis externa stood at 6.88% (Table 1). However, it is not always easy to determine the accurate prevalence of otitis externa in canine population, as mild cases are not always detected by the owner. Findings of the present study were in close agreement with a report by Carlotti (1991) who reported the prevalence rate of otitis externa as 5-12% respectively.

Table 1: Prevalence of otitis externa in dogs

Out of the dogs affected, 27 dogs had unilateral otitis externa and 15 dogs showed signs of bilateral otitis externa with a percent prevalence of 64.28 and 35.71 respectively (Table 2) with the involvement of 57 ears. Among the 27 dogs with unilateral otitis externa, 15 dogs (55.55%) had the infection of right ear and the remaining 12 dogs (44.44%) had the infection of left ear.

Table: 2: Type of otitis externa

In the present study, in different age groups i.e., upto 1 year, >1year to 3 years, >3 years to 5 years and >5 years was recorded as 17.54%, 29.82%, 19.29% and 33.33% respectively. High prevalence of otitis externa (19 out of 57 ears i.e., 33.33%) was seen in the age group of >5years (Table 3) and one explanation for this finding is that the age group between 5-8 years commonly suffers from well- established hypersensitivity diseases and disorders of keratinization (August 1986). Carlotti (1991), and Logas and Kunkle (1994) reported that otitis externa was common in dogs in the age group of five to eight years. On the contrary Nuttal (1998), and Zur et al., 2011, observed no age predilection in dogs suffering from otitis externa. Agnihotri et al., 2014 reported maximum prevalence of otitis externa in dogs of age between 1 and 3 years followed by dogs between 3 and 6 years of age.

Table 3: Age wise prevalence of otitis externa

Otitis externa was recorded in different breeds like German shepherd, Pug, Labrador retriever, Pomeranian, Dalmatian and others, of which higher prevalence was observed in Labrador Retriever (22.80%), followed by Pug (17.54%), German Shepherd (15.78%) and Pomeranian (14.03%) (Table 4).

Table 4: Breed wise prevalence of otitis externa

The difference can be explained by the fact that Labrador retriever, Pug, and German shepherd breeds are comparatively more popular breeds in the local area. However, Bass (2004) reported that Labrador retrievers have more apocrine tubular glands than other breeds, which predispose them to otitis externa. He also reported that breed related differences lead to otitis externa in many dogs. Similarly Pugh et al. (1974) stated that conformation abnormalities in Labradors produces an environment which favours the growth of yeasts either alone or in combination with staphylococcal organisms, resulting in otitis externa. On the contrary, Nuttal (1998) observed no significant difference between breeds in the occurrence of otitis externa.

In the present investigation, otitis externa accounted for 61.40% in male dogs and 38.59% in female dogs (Table 5). Since dog owners usually prefer male dogs as companion animals, it is quite possible that the higher prevalence recorded in male dogs might be primarily related to this selective preference of the pet lovers. The findings of the present study corroborate with the reports of earlier workers like Pugh et al. (1974) and Kiss et al. (1997) who also suggested higher occurrence of otitis externa in male dogs.

Table 5: Gender wise prevalence of otitis externa

On the contrary, Fernandez et al., 2006, reported that female dogs were more affected than males with otitis externa. Saridomichelakis et al., 2007, stated that otitis externa was observed in 45 males and 55 females out of 100 dogs with otitis externa in their study. However August (1988), Carlotti (1991), Nuttal (1998), and Zur et al., 2011 reported no indication of sex predisposition for canine otitis externa.

Conclusion

In view of recording the prevalence of otitis externa, screening of 610 cases presented at College veterinary hospital, revealed prevalence rate to be 6.88%. Right unilateral otitis externa was more common and highest prevalence was seen in the age group of > 5years. Male dogs were mostly susceptible and mostly seen in Labrador retrievers.

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