1. Otitis Externa
Acute or chronic inflammation of the external ear canal more
commonly seen in dogs than cats
• Common causes include parasites, hypersensitivity
reactions, foreign bodies, obstructions, and autoimmune
diseases
• Perpetuating factors include, but are not limited to,
bacterial overgrowth/ infections, yeast overgrowth/
infections, canal hypertrophy, cerumen gland hyperplasia
and adenitis
2. Pre-disposing Factors
• Otitis externa is more commonly seen in humid
environments, and in the summer months associated with
atopy.
• Idiopathic Glandular Hyperplasia of Cocker Spaniels,
Springer Spaniels, excessive hair in the ear canals (Cocker
Spaniels and Poodles), pendulous pinnae , and stenotic ear
canals (ex: Shar Peis).
• Dogs that swim a lot in the summer months often have a
greater risk
3. Clinical Signs Associated with
Otitis Externa
• Head shaking, rubbing, scratching, discharge from the
external ear canal, aural erythema, alopecia of the ear
pinnae, hyperplasia of the ear canal wall, hearing deficits
and possibily generalized skin disease
• Chronic/End Stage Otitis externa: Calcification of
auricular cartilage
4. How do you diagnose Otitis
Externa?
• History, clinical signs, physical exam
• findings bacterial culture and sensitivity
5. Treatment Options
• Topical or Systemic corticosteroids
• Antibiotics
- repeat cytology every two weeks to determine if
treatment is working and whether changes need to be made
• Antifungal drugs
• Ear flushing
• Resolution often takes up to 3-4 weeks (for the treatment
of mites)
6. References
• Brown, M., Christopher & Joseph J. Bertone (2001). The 5- Minute Veterinary Consult Equine. Lippincott Williams &
Wilkins, PA.
• Cote, Etienne (2007). Clinical Veterinary Advisor Dogs and Cats. Mosby Elsevier, Missouri.
• Stashak, S. Ted (2002). Adams’ Lameness In Horses (5th ed.). Lippincott Williams & Wilkins, PA.
• Tilley P. L. & Francis W.K. Smith Jr. (2007). Blackwell’s Five-Minute Veterinary Consult: Canine & Feline (4th ed).
Blackwell Publishing, Iowa.
