Ear disease

• Predisposing factors for ear disease - conformation

  Excessive hair growth in canals (e.g. poodle)

  Hairy concave pinna (e.g. cocker spaniel)

  Pendulous pinna (e.g. basset hound)

  Stenotic canal (e.g. Shar Pei)
• Predisposing factors for ear disease - Excessive moisture


  Environment (heat & high humidity)

  Water (swimmer‘s ear, grooming cleaners)
• Predisposing factors for ear disease - obstructive ear disease

  Feline apocrine cystadenomatosis.

  Neoplasia & polyps.
• Predisposing factors for ear disease - primary otitis media


  Primary secretory otitis in CKCS, tumour or sepsis.
• Predisposing factors for ear disease - treatment effects

  Altered normal microflora (e.g. inappropriate cleaner)

  Trauma from cleaning or plucking
• What are the primary causes of ear disease?

  Parasites:

  • Otodectes cynotis
  • Demodex spp
  • Scabies

  Foreign bodies:

  • Grass awns

  Hypersensitivty:

  • Atopic dermatitis, food hypersensitivity, medications

  Keratinisation disorders:

  • Primary idiopathic seborrhoea
  • Hypothyroidism

  Glandular disorders:

  • Cocker spaniels, English springer spaniels & Labrador retreivers have increased ceruminous glands

  Miscellaneous:

  • e.g. feline proliferative & necrotising otitis externa
• Otodectes cyanotis

  Common cause of otitis

  Hypersensitivity disease:

  • Carrier/non-clinically affected state
  • Ectopic disease

  Most ear creams are effective with localised disease:

  • Selamectin or moxidectin spot-on
  • Likely that the isoxazoline group are effective.

  May need a cleaner +/- steroids.
• Foreign body otitis

  Grass seeds most common:

  • Late spring to end of summer
  • Often stimulate violent response in the affected individual - sudden onset.
  • Check the other!
  • Can be hidden in discharge and migrate into the middle ear.

  Painful - chemical restraint is essential in most.

  Beware the hair that looks like a grass seed and vice versa
• Hypersensitivity otitis


  OE is a very common complication of atopic dermatitis and food allergy.

  Primary otitis is often not recognised and so inadequately treated and dogs and cats present when there is secondary infection.

  Prevention of recurrence:

  • Treat primary disease
  • Ensure perpetuating factors are treated
  • Ensure owner knows to intervene early
• What are the perpetuating factors of ear disease?

  Pathological changes in the external ear canal:

  • Changes in canal wall
  • Inflammation causing failure of epithelial migration.
  • Acute change: oedema, hyperplasia
  • Chronic change: Proliferative change, canal stenosis, calcification of pericartilagous fibrous tissue.
  • Otitis media
  • Acute - foreign material, mucoprurulent exudate.
  • Chronic - biofilm formation, granulation material, bony change in the bulla.
• What are the presenting reasons of otitis externa?

  Aural/otic pruritus or head shaking

  Mild to marked exudate.

  Malodour

  head tilt:

  • Neurological or pain

  Deafness:

  • Often conduction
  • May be toxic/neurological
• What are the physical findings of otitis externa?

  Erythema, swelling, scaling, discharge (otorrhea), malodour and pain.

  Secondary:

  • Pinnal lesions are common
  • Pyotraumatic dermatitis
  • Haematoma
• What is the disease progression of otitis externa?

  Secondary disease follows the primary cause.

  Many/ most cases are not presented until secondary disease is present.

  • Malassezia
  • Staphylococci
  • Gram negative rods
  • If treated inadequately potential for anti-microbial resistance
  • In many cases Pseudomonas aeruginosa is end point.
• What is the treatment for otitis media?

  If intact drum - perform myringotomy and flush until clean.

  Using cytology and culture data:

  • Use aqueous antibiotics (usually home prepared) 2-3 times a day following cleaning with saline or an appropriate aqueous cleaner.
• MRI for diagnosing ear disease

  Far better appreciation of soft tissue structures.

  Expensive - may take significant part of the clients budget.

  CT is often as useful and a much cheaper alternative in many cases.

  Consider when wider neurological diagnoses.
• What is the cause of otitis interna?

  Extension of otitis media (majority)

  Haematogenous and ascending infection via the auditory tube.

  Adverse drug reaction.
• What are the clinical signs of otitis interna?

  Head tilt to the affected side.

  Spontaenous or rotatory nystagmus.

  Asymmetric limb ataxia with preservation of strength.

  Falling

  Vomiting and/or anorexia
• What is the diagnosis and treatment or otitis interna?

  Establish the presence of systemic disease and/or localised disease (OE/OM).

  Pruritus, headshaking and pain around the TMJ may be useful indicators of local disease.

  Otic examination

  MRI (possibly CT)

  In the absence of another cause, long term use of systemic antibiotics has been advocated
• What does the nature of the ear exudate indicate?

  Dry coffee grounds - Otodectes cynotis

  Moist brown exudate - staphylococcus spp, Malassezia

  Prurulent yellow/green exudates (malodorous) - Gram-negative especially Pseudomonas sp.

  Ceruminous discharge (often little smell) - allergy, endocrine (especially hypothyroidism), keratinisation defects, Bacteroides spp
• Sampling of ear exudate

  Parasites (Otodectes and Demodex) - mix gently in LP and coverslip.

  Wax samples - poor stickiness, using straining rack, apply methylene blue only and coverslip.

  Prurulent samples - stain as for cytology
• What is a biofilm?

  A common finding in otitis due to bacteria (and yeasts).

  Biofilms = extracellular matrix material produced by bacteria, usually when the bacteria are in large numbers and in close proximity.

  Leading to lack of penetration of antibiotic and disinfectant agents.

  Increased difficulty in cleaning.
• What are the cytological reasons of otitis interna?

  Rods are seen. The most suitable antibiotic treatments can only be chased if the organisms are known.

  Marked prurulent or pyogranulomatous discharge without organisms being noted. Possibility of finding a pathogen that is relevant, but also may grow organisms that are irrelevant clinically.
• What are the clinical reasons for bacterial culture on otitis interna?

  In the event of treatment failure.

  If there is a suspicion of MRS species.

  If considering video otoscopy or ear flush for diagnosis or treatment in bacterial otitis as in the event of an adverse event following these procedures, systemic antimicrobials may be required.
• Ear cleaning products - Cleanaural

  Good cleaner

  Good antimicrobial properties

  Staph killed at 1/32 Pseudomonas killed at 1/8 and Malassezia killed at 1/32.

  However quite ’stingy’ in inflamed ear.

  Unlikely to be ‘otosafe’
• Ear cleaning products - epiotic

  Fair to good cleaner

  Fair to good antimicrobial properties - Staph killed at 1/2 Pseudomonas killed at 1/8 and Malassezia killed at 1/8.

  Dry effect on the canal.

  Comfortable in the ear.

  Probably not otosafe

  General purpose
• Ear cleaning products - Otodine

  Watery cleaner

  Doesn’t sting.

  Poor ceruminolytic action.

  Good to fair antimicrobial properties:

  • Staph killed at 1/2
  • Pseudomonas killed at 1/8
  • Malassezia killed at 1/8

  Appears otosafe in the dog

  Prurulent otitis
• Ear cleaning products - Cerumaural & Otoact


  Dissolve and mobilise waxy, greasy discharge.

  No antimicrobial properties

  Considered to be otosafe

  Cerumaural greasier than Otoact

  Waxy (ceruminous) otitis.
• Ear cleaning products - TRIZ EDTA

  Poor ceruminolytic properties

  No antimicrobial activity (by itself)

  Appears otosafe

  Pre-treatment and base for other treatments only.

  Base for additions or as pre-flush.
• Ear cleaning products - TRIZ EDTA with added N-acetyl cysteine


  Disrupts biofilm

  Some antimicrobial activity

  Appears to be otosafe

  May be irritant in the inflamed ear.

  Biofilm busting
• Treating otitis


  Remove/reduce microbes

  Reduce swelling, discomfort or pain.

  Normalise canal lumen and function.

  Polypharmacy is the rule - medications contain:

  • Antibiotic
  • Antifungal
  • Anti-inflammatory
• Inflammatory otitis due to CAD, no overgrowth

  Treat underlying inflammation with a local or systemic drug. Cleaner in this situation may be unhelpful.
• Cocci bacteria &/or yeast overgrowth with minimal inflammation

  Likely waxiness of exudate.

  Antibiotic/antifungal not needed.

  Treat infection alone with topical steroids and cleaner.

  Erythroceruminous otitis externa
• Cocci bacteria &/or yeast infection consistent inflammation

  Appropriate poly pharmacy product (narrow spectrum or without essential use in human medicine).

  Prurulent otitis externa.

  Relatively low risk of tympanic rupture, low waxiness of the exudate
• Rod infection +/- cocci & yeast significant inflammation

  Appropriate poly pharmacy product, lilely systemic steroids and use antibiotics with good action in pus. Consider possible otitis media.

  Medium risk of tympanic rupture. Low likeliness of waxiness of the exudate.

  Prurulent otitis externa
• Chronic severe inflammatory otitis externa usually rods

  Appropriate poly pharmacy product. Systemic steroids and possibly flush under GA. Likely biofilm, drum likely compromised.

  High risk of tympanic rupture, low likeliness of waxy exudate.

  Prurulent otitis externa.
• What are the three treatment principles of ear disease?


  Remove/reduce microbes.

  Reduce swelling, discomfort and pain.

  Normalise canal lumen and function.
• Erythroceruminous otitis


  Clinically:

  • Red, why itchy ear.
  • Often a feature of allergic skin disease.

  Cytology shows cocci +/- Malassezia, squames, but no neutrophils:

  • Microbial overgrowth.

  Treat:

  • Cleaner appropriate for the level of discharge
  • Corticosteroid alone.

  
• What is the treatment for acute prurulent otitis?

  First line ointment based on cytology and otoscopy.

  Once to twice daily therapy 7-14 days.

  • Canaural/ Surolan/ Easotic
  • Sufficient amount.

  Alternatively, Neptra or Osurnia (once or twice respectively).

  Combined with a suitable cleaner e.g.

  • Otodine/TRIZChlor - watery, disinfectant and doesn’t sting
• Chronic allergic otitis

  Long term Malassezia and S.pseudintermedius dysbiosis and overgrowth.

  Treat the ear prophylactically with steroids +/- steroids cleaner to prevent flares.

  Currently no products with marketing authorisation for this use.

  Commonly used products include, Cortavance (hydrocortisone aceponate spray), dexamethasone diluted in sterile water or by adding dexamthasone to cleaning products.

  This usually results in better overall control and prevents flares.
• What are the clinical signs of Pseudomonas otitis


  Redness, pruritus, pain and discharge, often accompanied by ulceration and pain.

  Often secondary features of lichenification around the pinna and perpetuating changes in the canal.

  Often obvious malodor.