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An Urban Experience
WSVA7-0294
DERMATOLOGY
DIAGNOSIS OF OTITIS EXTERNA AND MEDIA
T. Nuttall1
1University of Edinburgh, Royal Dick School of Veterinary Studies, Roslin, United Kingdom
DIAGNOSTIC APPROACH TO OTITIS EXTERNA AND MEDIA
Dr Tim Nuttall
Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Roslin, UK.
tim.nuttall@ed.ac.uk
Introduction
The initial diagnosis of otitis is straightforward, but
further examination and tests are needed to identify the organisms and extent of inflammation to select the most appropriate treatment. It is also important to determine the primary, predisposing, perpetuating and secondary factors in cases of chronic and recurrent otitis. Diagnostic steps include:
• Signalment and history
• Clinical examination
• Otoscopy or video otoscopy
• Cytology
• Culture and antimicrobial susceptibility testing
• Imaging – radiographs, CT and/or MRI Signalment and history
Clinical examination
Erythroceruminous otitis
Erythema and a ceruminous discharge; erosions and ulcers are rare. The inflammation, discharge and chronic pathological changes vary from mild to severe. The
ears are more pruritic than painful. Staphylococci and Malassezia are most common.
Suppurative otitis
Pain, inflammation, ulceration, hemorrhage and purulent discharge. Pseudomonas is most common, but Proteus, other rods, staphylococci or streptococci can also be found. Malassezia is rare.
Clinical features of common primary causes of otitis
· Otodectes are associated with dry, dark brown, waxy debris. Mites may be seen in the canal or on microscopic examination of cerumen. They may be difficult to find if there is a hypersensitivity and low mite numbers.
· Atopic dermatitis and adverse food reactions are the most common cause of recurrent otitis in dogs; otitis may be the only clinical sign, but most dogs have skin lesions elsewhere. There is a diffuse erythema of the ventral pinna and vertical ear canal. Eosinophilic granuloma syndrome lesions may
be seen in the ear canals of cats with or without lesions elsewhere.
· Contact reactions to topical medications result in ongoing inflammation and a white to purulent discharge with mature non-degenerate neutrophils but few organisms. There is often a history of an initial response followed by relapse and pain on administration.
· Immunosuppressive diseases include hypothyroidism, hyperadrenocorticism and sex hormone alopecias (seborrhoeic otitis externa).
· Keratinisation disorders result in scaling and seborrhoea of the pinnae and ear canals.
· Immune-mediated diseases can cause ulceration and inflammation of the pinnae and the ear canals. Pustules on the concave aspect of the pinna are common with pemphigus foliaceus. Punched out ulcers and notches can be associated with vasculitis. Juvenile cellulitis causes severe oedematous otitis in young puppies.
· Ceruminous gland tumours (rarely other tumours) can obstruct the ear canal and cause otitis. External tumours can compress and infiltrate the ears.
· Foreign bodies (e.g. grass seeds) are usually easily seen and removed, but might need flushing out under sedation.
· Feline naso-pharyngeal polyps may originate from the naso- pharynx, auditory tube or middle ear. Most have otitis media with or without otitis externa.
· Ceruminous/sebaceous hyperplasia is seen in Spaniels, and occasionally other breeds and cats.
   Young Old
  Otodectes; inflammatory polyps (cats) Neoplasia
   Breed
 Atopic dermatitis Keratinisation defects (cocker spaniels) Primary secretory otitis media (PSOM) (CKCS and brachycephalics)
   Conformation & anatomy
  Hairy ears and/or narrow ears Ceruminous hyperplasia Pendulous pinnae (spaniels)
   Sex
  Sertoli cell tumour
   Acute onset
   Foreign body, immune-mediated diseases
   Recurrent disease
  Underlying primary condition
   Chronic disease
 Underlying primary condition Perpetuating factors Antimicrobial resistant infection
   Unilateral
  Neoplasia, polyp, foreign body
   Bilateral
   Generalised underlying condition
   Contagion
 Otodectes, Sarcoptes, dermatophytosis
   Management
   Swimming Ear cleaning and/or plucking hairs
   Other clinical signs
 Demeanor, appetite, polyuria/polydipsia, pruritus etc.
   Seasonality
  Atopic dermatitis, foreign bodies, trombiculids, biting insects
 Previous treatment
 Response to treatment Contact reaction
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 42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS
  































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