CHAPTER 37 OTITIS EXTERNA, MEDIA, AND INTERNA 553
Fig. 37.4.Suppurative otitis externa with secondaryPseudomonas aeruginosainfection in an adult male-
castrate mix-breed dog.Pseudomonasspp. infection often causes a foul-smelling, yellow-green exudate with
erosion and ulceration of the epithelial lining of the canal. Mucoid appearance to the discharge may indicate
biofilm production.
Fig. 37.5.Polypoid cerumen gland hyperplasia causing functional obstruction of the external ear canal in an
11-year-old male-castrate cocker spaniel.