Image Quiz: Chronically pruritic and odoriferous ears in a basset hound (Sponsored by Intervet/Schering-Plough Animal Health), Answer D
Correct! Performing a cytologic examination of the ear exudate is simple and provides valuable information rapidly. The exudate from this patient exhibits abundant numbers of large (much larger than bacteria), oval to peanut-shaped budding organisms. Based on this dog’s signalment, the characteristic appearance and smell of the exudate, and cytologic examination results, Malassezia otitis externa should be suspected. Malassezia dermatitis and otitis externa occur frequently in basset hounds. The gross appearance of exudate resulting from Malassezia otitis externa can be yellow to dark brown and is usually waxy in consistency. Cytologic examination of the exudate reveals the characteristic budding organisms described. Guidelines for quantitative yeast counts needed for significance are not reliable as they can be affected by factors such as smear thickness. Moreover, in a patient that is hypersensitive to Malassezia pachydermatis, only a few yeast organisms may be clinically significant.
Acknowledgement: The author wishes to thank Ross Bond, DVM, BVMS, PhD, DVD, MRCVS, DECVD, for the use of the photo in this quiz and for his technical guidance.