Otitis Externa/Media in Cats & Dogs (Santoro) Flashcards
Otitis externa
Inflammation of the ear canal
Otitis media
Inflammation of the bulla
Otitis interna
Inflammation canaliculi and/or cochlea
Predisposing factors of otitis externa
- Conformational defect (hair, stenosis)
- Swimming/humidity
- Obstructive ear disease (neoplasia, polyps, foreign body)
- Trauma
- improper ear cleaning
- topical irritants
- Excessive cerumen production
- Systemic dz (catabolic states, immune suppression, debilitation)
Primary factors of otitis externa
- Disease, enough for inflammation
- Foreign bodies
- Allergies
- Autoimmune diseases
- Endocrinopathies
- Parasitic diseases
- Masses
Otodectes cynotis (ear mite)
- Non-burrowing psoroptid mite
- On skin surface
- Protected by thick, brown (coffee ground) crust
- Feed on lymph & blood
Primary factor of OE
Otobius megnini (spinous ear tick)
- Larvae & nymphs induce inflammation
- Drops to ground as adult
Primary factor of OE
Eutrombicula alfreddugesi (chigger)
- Bite causes irritation & variable pruritis
- Seasonal - late summer/fall
Primary factor of OE
Otodemodicosis
- More common in cats
- Ceruminous otitis externa
- Suspect immynosuppression
- FeLV, FIV, diabetes, neoplasia
- Ear swab, no need to scrape
Primary factor of OE
Sacroptes scabiei canis (canine scabies)
- Usually ear tips, but can be otitis externa
- Severe pruritis
- Female burrows in epidermis and layws eggs
- Thick, yellow crusts
Primary factor of OE
Notoedres cati (feline scabies)
- Medial, proximal pinnae
- Face, eyelids, neck, feet, perineum
- Female mites burrow
- Intense pruritis
- Highly contagious
- Abundant mites
Primary factor of OE
Intraluminal tumors
- Relatively uncommon
- Obstructive lesions
- Ulceration & necrosis
- Malignant (cats > dogs)
- Ceruminous gland adenocarcinoma
- Squamous cell carcinoma
- mast cell tumors
Primary factor of OE
Nasopharyngeal polyp
- Congenital, bacterial, calicivirus
- Chronic uni/bilateral otitis, mass in ear canal, head tilt
- Treat surgically
Primary factor of OE
Apocrine cystomatosis
- Cysts of apocrine glands
- Adult animals
- Solitary, well-circumscribed, smooth, bluish tense swelling
- Located on concave surface of pinna, vertical ear canal
- Uni or bilateral
- Treat: benign neglect, surgery
Primary factor of OE
Atopic dermatitis
- Erythema & inflammation
- Initially pinnae, vertical canal
- Entire ear canal when chronic
Primary factor of OE
Causes of contact allergy in the ear
- Neomycin/gentamycin
- Miconazole 1%
- Propylene glycol
Primary factor of OE
Primary idiopathic seborrhea
- Incr. cerumen production
- Altered cerumen composition
- Delayed desquamation and stenosis
- Often progress to calcifying otitis externa/media in cocker spaniel
Primary factors of OE
Endocrinopathies as a primary factor of otitis externa
- Hypothyroidism, sex hormone imbalance
- Incr. mucin deposition in dermis
- Hyperplasia/hyperkeratosis of epidermis
- Altered fatty acid production
Primary factor of OE
Autoimmune diseases as primary factors of otitis externa
- Pemphigus foliaceus
- Pemphigus erythematosus
- Systemic lupus erythematosus
Juvenile cellulitis
- Puppies
- Vesiculopustular dz
- Dachshunds, golden retrievers, pointers
- Purulent otitis w/ head & facial lesions
- Blepharitis
- Lymphadenopathy
Primary factor of OE
Secondary factors of otitis externa
- Infection secondary to the inflammatory process
- Bacteria
- Yeast