Chronic Canine Otitis
Robert A. Kennis DVM, MS, DACVD
Canine and feline otitis continues to be one of the most requested topics for continuing
education seminars. The multi factorial components make diagnosis and treatment more
complicated than other dermatologic diseases. Compounding the difficulty of treatment is the
limited number of otic preparations licenced and safe for instillation into the ear canal. The
focus of this presentation will center on treatment options for refractory otitis. A brief discussion
on the predisposing and primary causes of otitis will also be covered. Because feline otitis and
treatment there of can be very different, comparative aspects will be addressed. Finally, surgical
options of treating otitis will be reviewed.
Otitis externa is defined as an acute or chronic inflammation of the ear canal and or
pinnae. It may be unilateral or bilateral. Otitis media describes inflammation beyond or
including the tympanic membrane (ear drum) and bullae. Otitis interna is reserved for cases of
documented neurologic symptoms including vestibular signs.
The causes of otitis are best evaluated as predisposing, primary, and perpetuating factors.
Usually there are many factors involved and otitis should not be viewed as mainly a bacteria or
yeast infection. On physical examination, it is usually these perpetuating factors that get all the
attention. Obviously, we need to resolve the bacteria or yeast component but we must ask
ourselves “what is a nice healthy dog doing with an ear infection?”
Predisposing factors are those that make the conditions favorable for an otitis situation to
occur. Stenotic ear canals are the classic predisposing factor. However, stenotic ear canals can
also be considered a perpetuating factor in a chronic infection situation. Inappropriate topical or
systemic medications can be predisposing factors. Ear canal maceration due to excessive
moisture from swimming or bathing can disrupt the epithelial barrier enough to allow