Canine Otitis Externa and Otitis Media Study Guide

Overview and Clinical Importance

Otitis externa is an inflammatory condition of the external ear canal affecting approximately 10-20% of canine patients presenting to veterinary practices. It represents one of the most common dermatological complaints in dogs and is a frequent topic on the NAVLE. Understanding the multifactorial nature of otitis, including primary causes, secondary infections, predisposing factors, and perpetuating factors (PSPP classification), is essential for successful diagnosis and management.

Otitis media (middle ear inflammation) occurs in 50-89% of dogs with chronic otitis externa and significantly complicates treatment. Foreign bodies, particularly grass awns (foxtails), represent an important primary cause of acute, often unilateral, otitis that requires prompt identification and removal.

Anatomy of the Canine Ear

External Ear

The canine external ear consists of the pinna (auricular cartilage) and the external ear canal. The ear canal is L-shaped, composed of a vertical canal (approximately 2.5 cm long, runs ventrally from the pinna opening) and a horizontal canal (extends medially at approximately 75-degree angle to the tympanic membrane).