Chronic Otitis in Cats: Clinical management of primary, predisposing and perpetuating factors

Abstract

Practical relevance: Chronic otitis can be one of the most frustrating diseases to manage for a small animal practitioner. While it occurs less commonly in the cat than the dog, it is no less challenging. The purpose of this review is to discuss the common and uncommon causes of chronic otitis in the cat within the clinical framework used for diagnosis and treatment. The focus is on diseases that affect the ear canal, rather than those restricted to the pinnae.

Clinical challenges: Otitis is multifactorial, which complicates management. A common clinical mistake is to focus solely on treating the infection present. Only by addressing all factors will a clinician successfully control chronic otitis. For the purposes of this review, the authors have adopted the established model of separating primary, predisposing and perpetuating causes of otitis. Primary factors are those that directly cause otitis (inflammation); predisposing factors are those that put the patient at risk for development of otitis; and perpetuating factors are those that result in ongoing clinical signs of otitis or that prevent clinical resolution.

Audience: This review is aimed at veterinarians who treat cats and particularly those with an interest in feline dermatology and otology.

Equipment: While many practitioners rely on a hand-held otoscope, a video-otoscope can be very helpful for the diagnosis and treatment of chronic otitis.

Evidence base: This review presents up-to-date information regarding the diagnosis and treatment of chronic otitis in cats, with emphasis on the most recent peer-reviewed literature.

Keywords: Chronic otitis; Otodectes cynotis; inflammatory aural polyp; otitis externa; otitis media.

Figure 1

CT of a 6-year-old castrated male domestic shorthair cat with unilateral otitis media and otitis externa. Note the bony septum (arrow) that divides the medial (M) and lateral (L) compartments of the tympanic bulla. On the left side, there is fluid filling the bulla, and the bulla and septum are sclerotic secondary to chronic otitis media

Figure 2

Cytology from a normal feline ear with mild staining artifact

Figure 3

Proliferative and necrotizing otitis externa in a 1-year-old castrated male Siamese cat; (a) at initial presentation and (b) after 1 month of therapy with oral ciclosporin, topical tacrolimus 0.1% ointment, and systemic and topical antimicrobials to treat secondary infection

Figure 4

Otoscopic image of an inflammatory aural polyp in the ear canal of a 1-year-old spayed female domestic shorthair cat

Figure 5

One of the authors (BB) examines the ear canal of a 2-year-old castrated male domestic shorthair cat with otic pruritus using a video-otoscope

Figure 6

Ceruminous gland cystomatosis in a 12-year-old spayed female domestic mediumhair cat