CANINE
Welcome to the NAVLE Canine Dermatology section, your go-to resource for mastering key dermatological topics in canine patients.
This section provides detailed notes on common skin conditions such as atopic dermatitis, pyoderma, mange, and fungal infections. You'll gain insights into their pathophysiology, clinical presentation, diagnostic techniques, and effective treatment strategies.
Designed to support your NAVLE preparation, these notes also highlight essential preventive care practices and management tips, ensuring a comprehensive understanding of canine dermatology.
Notes:
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Practice what you’ve learned by reviewing our sample NAVLE-style questions — click here to get started!
Explore additional sections of the NAVLE Canine Notes:
NAVLE Sample Questions:
Question 1:
A 4-year-old Cocker Spaniel presents with chronic otitis externa that has not responded to empirical antibiotic treatment. Otoscopic examination reveals thickened ceruminous debris and stenosis of the vertical ear canal. Cytology shows numerous cocci and neutrophils. What is the most appropriate next diagnostic step?
A) MRI of the ear canal
B) Myringotomy with middle ear culture
C) Deep ear flush under anesthesia and culture
D) Topical glucocorticoid therapy trial
Question 2:
Which of the following organisms is most commonly associated with chronic, recurrent otitis externa in dogs and has a characteristic “budding” peanut shape on cytology?
A) Staphylococcus pseudintermedius
B) Pseudomonas aeruginosa
C) Malassezia pachydermatis
D) Proteus mirabilis
Question 3:
A 6-year-old Labrador Retriever is undergoing treatment for Pseudomonas-associated otitis externa with topical gentamicin. The dog begins to show signs of head tilt, ataxia, and horizontal nystagmus. What is the most likely cause of these new clinical signs?
A) Intracranial extension of infection
B) Congenital vestibular disease
C) Ototoxicity from topical gentamicin
D) Vestibular neuronitis
Answer & Explanation
Question 1:
Correct Answer: C) Deep ear flush under anesthesia and culture
Explanation:
This dog has signs of chronic, possibly resistant otitis externa. A deep ear flush under anesthesia allows better visualization, removal of debris, and sample collection for cytology and bacterial culture and sensitivity, which is critical to guide targeted therapy. Cocker Spaniels are predisposed to chronic otitis due to conformation and ceruminous gland hyperplasia.
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A myringotomy is more appropriate if otitis media is suspected but not first-line.
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Topical glucocorticoids are helpful adjuncts but not sufficient as a next diagnostic step.
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MRI is used to evaluate deeper tissues, such as for suspected otitis media/interna or masses, but not first-line.
🔗 Further reading:
Merck Vet Manual - Otitis Externa
Question 2:
Correct Answer: C) Malassezia pachydermatis
Explanation:
Malassezia pachydermatis is a yeast organism commonly associated with chronic otitis externa in dogs. It appears as oval to peanut-shaped organisms with budding when stained with Diff-Quik. It often accompanies allergic dermatitis or endocrine disorders, contributing to inflammation and cerumen overproduction.
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Staph pseudintermedius is a common bacterial pathogen but not yeast.
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Pseudomonas aeruginosa causes resistant otitis, often with ulceration.
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Proteus mirabilis is less common and usually part of polymicrobial infections.
🔗 Further reading:
Merck Vet Manual - Otitis Externa: Etiology
Question 3:
Correct Answer: C) Ototoxicity from topical gentamicin
Explanation:
Gentamicin and other aminoglycosides are ototoxic, especially if the tympanic membrane is ruptured or the drug penetrates into the middle or inner ear. Clinical signs such as vestibular dysfunction (head tilt, ataxia, nystagmus) suggest inner ear involvement. The risk increases with chronic inflammation and barrier disruption.
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Intracranial extension is rare and would present more severely.
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Congenital disease occurs in younger dogs.
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Vestibular neuronitis is rare and idiopathic; drug toxicity is more likely in this context.
🔗 Further reading:
Clinician’s Brief - Managing Canine Otitis
