ASK THE EXPERT h OTOLOGY h PEER REVIEWED

Examination of the Ear

Louis Norman Gotthelf, DVM Animal Hospital of Montgomery Montgomery, Alabama

Pinnal & Preauricular YOU HAVE ASKED ... 1 Skin Examination CAUSES OF How should I conduct thorough Examination of the pinnae to assess for PINNAL DISEASE primary and secondary lesions can help ear examinations in my patients? formulate a list of differential diagnoses h Trauma and diagnostic tests (see Causes of Pin- h Hematoma nal Disease). Lesions found on the pin- THE EXPERT SAYS ... h Ectoparasites nae may also suggest conditions such as A thorough physical examination of the allergy, inflammatory/autoimmune con- h Immune-mediated ear should include 3 independent parts: ditions, infections, and infestations. disease h Keratinization defects 1. Pinnal and preauricular skin Pustules on the pinnae (Figure 1) can h Malassezia examination suggest either infectious (eg, pyoderma) spp and dermatophytes 2. Otoscopic examination or sterile disease (eg, pemphigus folia- 3. Tympanic membrane assessment ceus). Cytologic examination of the pus- h Neoplasia tules may show acantholytic cells and h Atopic and contact neutrophils indicative of pemphigus. dermatitis Neutrophils and bacteria can be seen in h some infectious causes of pustules. Papu- Endocrine disorders lar eruptions may also be seen with para- sitic diseases.

64 cliniciansbrief.com December 2016 Thick scale and erythema of the pinnal folding in pendulous-eared dogs may margins, particularly the apices, may indicate fly strike or mosquito bite VISUAL indicate sarcoptic mange, especially hypersensitivity in cats. Traumatic EXAMINATION when a “pinnal-pedal” scratch reflex injury to the pinna may mimic other OF THE EAR occurs in response to rubbing of the pin- conditions. CANAL nae. In addition, erythema, crusts, and h scale may be present with demodicosis Lichenification, erythema, hyperpig- The canine ear canal consists of overlapping or dermatophytosis. Low-power exam- mentation, and glandular hyperplasia of cartilage plates in a bent, ination of skin scrapings placed in min- the concave pinnae may indicate chronic funnel-shaped, tapered, eral oil on a microscope slide may help allergic dermatitis, often with concur- cylindrical structure that identify the presence of parasites. Fun- rent otitis externa. When found in provides the “L” shape to gal culture may be indicated. cocker spaniels, this may be a manifes- the vertical and tation of primary idiopathic seborrhea horizontal ear canals. If vasculitis is suspected as a result of associated with ceruminous otitis.3 Cats have more of an arc ulceration, necrosis, notching, and/or Topical drug reactions—particularly to shape to their ear canal scarring of the pinnal margin, a biopsy neomycin-containing otic medications— than do dogs. Before may be necessary to examine for capil- may also result in pinnal erythema and/ inserting the otoscope, lary thrombosis. Ear margin seborrhea, or erosions or ulcerations. palpation of the vertical a nonpruritic primary cornification ear canal should be performed to assess defect often found in dachshunds and Many pinnal tumors exist, including cartilage plasticity. Any Yorkshire terriers, may result in kerati- ceruminous gland adenomas in dogs pain or bony changes to naceous debris or alopecia along the ear and squamous cell carcinomas in the cartilage should be 1 margins. Cytologic examination of white-eared cats. noted. secretions may disclose colonization by h Malassezia spp. Bacterial and yeast otitis externa are typically confined to the ear canal A pinna that is no longer erect may indi- and/or pinnae. However, cate ear pain. Palpation of the pinnal bacterial exudates from cartilage, especially at the ear base, may chronic otitis externa indicate bony changes suggestive of pooling in the horizontal chronicity. Aural hematoma typically canal can cause erosion indicates pain or pruritus in the ear and of the eardrum leading to can result from violent head shaking, secondary otitis media or trauma, or autoimmune diseases.2 An interna. With neoplasia, aural hematoma on one side may result trauma, or severe otitis from otitis externa in the opposite ear. externa, extension of infection to surrounding tissues (cellulitis, abscess) Excoriation of the pinnal surface indi- is possible. cates self-trauma from pruritus that is often caused by otitis externa. Pinnal dermatitis and crusting with accumula- tion of purulent material on the base of the concave pinna may result from severe suppuration with otitis externa. d FIGURE 1 Pinnal erythema on the concave Hemorrhagic crusting of the ear tips of surface in an English bulldog with atopy. Note erect-eared breeds and of the pinnal the presence of pustules and papules.

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Otoscopic Examination In most dog breeds, the narrower horizontal 2 In nonanesthetized patients, an oto- ear canal has significantly fewer hair follicles scope cone of the proper diameter is gently with minimal glands. The exceptions are the inserted into the vertical ear canal. Once the American cocker spaniel, which has more ear canal lumen is centered in the eyepiece, glandular tissue density along the ear canal the otoscope cone is advanced deeper into the than do many other breeds,4 and the stan- ear canal. This technique avoids painful dard poodle, which anecdotally seems to scraping of the sides of the ear canal. have a higher density of hair follicles along the ear canal. As the canal narrows and bends, the pinna is grasped gently and moved outward and downward to straighten out the ear canal. After making the bend into the horizontal ear canal and advancing the speculum, the eardrum should be visualized (Figure 2).

In nonclinical dogs without any apparent signs of otitis externa, only a quick otoscopic examination is necessary. After a veterinar- ian becomes familiar with the normal canine and feline ear, pathologic changes should be easy to identify.

Some patients—healthy or otherwise—will require sedation or anesthesia. Sedation is also recommended for any patient that is markedly painful and/or fails to respond to d FIGURE 2 Examination of the ear with an otoscope. The empiric therapy. This is especially important pinna is elevated to examine the vertical ear canal and is for patients with unilateral ear disease as a gently pulled down and out to examine the horizontal source of discomfort (eg, foreign body lodged ear canal. in the ear canal).

The Ear Canal The ear canal is lined by a modified epidermis. The wide vertical ear canal con- tains hairs surrounded by sebaceous glands, as well as aprocrine glands unassociated with hair follicles. The normal vertical ear canal glistens because of the cerumen coating (Fig- ure 3). On examination of the ear canal with the otoscope, the skin of the vertical and hor- izontal ear canals should be nonerythema- tous. The epithelium of the ear canal is d FIGURE 3 Normal canine vertical canal. Blood vessels smooth. A network of blood vessels in the are visible in the dermis through the thin epithelium. A dermis is present. glistening coating of cerumen is present on the epithelial surface.

66 cliniciansbrief.com December 2016 Cerumen Cerumen is composed of apocrine (watery) and sebaceous (lipid) secretions as well as desquamated keratinocytes. Normal ceru- men coats the epithelium, protects against pathogens, and aids in prevention of water loss from the ear canal epithelium. Its sticki- ness helps trap particles and other debris.

In human cerumen, antimicrobial lipids (eg, sapienic and lauric acids) and antimicrobial peptides can be beneficial against many fungi d FIGURE 4 Cerumen gland hyperplasia. Inflammation in and bacteria. These substances have yet to be the ear canal results in increased secretions from the identified in canine or feline cerumen.5 Ceru- apocrine glands, which enlarge above the epithelial men changes its composition in the presence surface. of disease; it becomes less waxy and more hydrated. Normal cats have scant, thin ceru- Parasites men but may produce excessive cerumen in Live ear mites may be seen via otoscope response to diseases such as atopy or endo- crawling along the epithelial surface when crine disease. a patient’s head is held as still as possible. Cats tend to have larger numbers of mites; Removal of mild cerumen accumulations in the white-colored mites in the ear canal are normal ears using ear cleaners is not recom- seen crawling along the dark brown otic mended. The normal process of epithelial secretions. Other parasites (eg, ticks, flies) or migration removes accumulated ceruminous foreign material (eg, grass awns, seeds) may secretions as the surface epithelial cells be seen in the canal. move toward the outside of the ear canal to maintain ear health. In many ear diseases, Stenosis & Swelling this physiologic cleaning mechanism is dis- Any change in the epidermis, such as with rupted and copious cerumen accumulates in ceruminous gland hyperplasia or ulceration, the ear canal. is significant and should be noted Figure( 4). In a patient with inflammatory ear disease, Hair Loss thickening of the epithelium may obscure Clinical signs of otitis with exudate in the ear visualization of blood vessels. The clinician canals may result in a depilatory effect from should assess for presence of stenosis. caustic enzymes dissolving the keratin that Some dog breeds (eg, shar-peis, pugs) have comprises the hairs—similar to the hair loss small-diameter ear canals as part of their seen on the body in the form of an acute, moist standard conformation. Differentiation dermatitis or hot spot. Clinically, this is iden- between swelling and stenosis is necessary. tified as an absence of hair found in the ear Stenosis results from permanent pathologic canal during the acute phase of otitis externa. changes within the epidermis of the ear canal With resolution of ear disease, hairs will (Figure 5, next page). regrow as the epithelium returns to normal, and new hair growth can be seen on otoscopic examination at recheck. FOR RELATED VIDEOS, GO TO cliniciansbrief.com/article/examination-ear

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d FIGURE 5 Stenosis of the ear canal can result from d FIGURE 6 Ulceration of the ear canal. Note the sebaceous hyperplasia, inflammation, or scarring. disruption of the surface epithelium.

d FIGURE 7 Multilobulated tumor mass in vertical ear d FIGURE 8 Dark waxy exudate in a patient with canal Malassezia spp otitis

For swelling of the ear canal caused by often associated with a severe, chronic bacte- inflammation, it may be necessary to delay rial otitis externa (often Pseudomonas spp). a complete examination of the ear canal until The bacteria releases cytopathic enzymes anti-inflammatory therapy (eg, systemic resulting in ulceration (Figure 6). Tumors or topical corticosteroids) decreases the within the ear canal may be present and swelling. should be noted (Figure 7).

If changes do not reverse, the prognosis for Exudates medical management is poor, and total ear Note the character and volume of exudates. canal ablation and/or bulla osteotomy is rec- In general, a presumptive diagnosis of the ommended. If the ear canal epithelium is infection type can be made based on texture smooth and pink in color but the ear canal and color. Dark brown waxy or dry exudates diameter is narrowed, hyperplasia of the suggest yeast otitis in dogs or ear mite infes- sebaceous glands may be present. tation in cats (Figure 8). In dogs, creamy, tan-colored moist exudates tend to suggest Ulceration gram-positive (eg, Staphylococcus spp) bacte- Ulceration of the ear canal epithelium is most rial infections (Figure 9).

68 cliniciansbrief.com December 2016 d FIGURE 9 Tan, creamy wax in a patient with d FIGURE 10 Purulent moist material in the ear canal in a staphylococcal otitis patient with Pseudomonas spp otitis

d FIGURE 11 Hairs in the horizontal ear canal d FIGURE 12 Feline nasopharyngeal polyp in the obstructing the view of the eardrum horizontal ear canal

Purulent liquid or mucoid exudates with a move from the middle ear to the external ear white, yellow, greenish, or black color may canal through a hole in the eardrum. indicate a gram-negative (eg, Pseudomonas spp) bacterial infection (Figure 10). Hemor- All otic exudates should be sampled for cyto- rhagic exudates can indicate ulceration of the logic examination to characterize the type of ear canal or ulceration of a tumor mass. An organisms present (ie, cocci, rods, yeast). An ear canal epithelial examination may not be erythemic and exudative ear canal may often possible until the exudates are flushed out of result in pruritus and pain without infection. the ear canal and the epithelial surface is This would support inflammatory disease of a exposed. primary nature (eg, allergy).

Mucus should never be found in the external Additional Considerations ear canal; there are no goblet cells in the epi- Bacterial culture and antibiotic susceptibility thelium. Goblet cells abound in the lining of testing may be helpful to determine appro- the middle ear, which is a mucous membrane. priate treatment, especially in refractory Excessive amounts of mucus can be found in cases. Bacterial culture rarely reports growth the middle ear when it is inflamed and may of Malassezia spp yeasts; therefore, sending a

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culture off without cytology may result in tion along the floor of the horizontal canal. information that has no bearing on the otitis These hairs can be seen occluding the view of case being treated. Some bacteria cultured the eardrum (Figure 11, previous page). from the ear may not be the pathogen(s) per- petuating the ear disease. A feline inflammatory polyp originating from the middle ear may also be seen as a fleshy There is significant variability in antibiotic mass protruding into the horizontal canal susceptibility testing among reference labora- (Figure 12, previous page). tories.6 Susceptibility testing may be used as a guideline in selecting topical ear therapy. The Tympanic Membrane Assessment author’s preferred tools for determining 3 Examination of the tympanic membrane The eardrum whether an antibiotic is helping include fol- (ie, eardrum) is crucial and can be performed must be low-up ear examinations to assess clinical in almost all healthy patients without sedation. examined to improvement and comparative cytologies to determine if it determine the presence, reduction, or absence The eardrum has 2 parts: is normal or damaged or if of microorganisms from previous examina- purulent, tions. Resistance to an antibiotic on suscepti- h Pars flaccida: an upper, fleshy, vascular ceruminous, or bility testing may be misleading when treating portion keratinaceous exudates are otitis externa, as these susceptibilities are h Pars tensa: a thin, translucent portion present in the reported for blood levels. Topical antimicro- bulla behind it. bial levels may be hundreds of times more con- The pars tensa transmits sound vibrations centrated in the ear canal and may be effective through the bones of the middle ear to the in the face of reported in vitro resistance. cochlea. Embedded in the pars tensa is the manubrium (handle) of the malleus bone. In Ceruminoliths, concretions of dried medica- dogs, there is a gentle hook to the malleus tions, and foreign bodies are more often seen that points rostrally; in cats, this structure is in the horizontal canal. Occasionally, epilated thinner and straight. The pars flaccida pro- hairs will fall into the horizontal canal and vides the blood vessels that feed the pars become embedded in the thick wax accumula- tensa (Figure 13).

An area of germinal epithelial cells several cell layers thick covers the malleus bone along the pars tensa. The epithelial cells of this germinal center replace themselves regu- larly, and the older cells move off the ear- drum toward the horizontal ear canal, carrying any debris present on these cells. This keeps the eardrum pliable and relatively free of cerumen accumulation.

Damage to the tympanic membrane caused by trauma (eg, chewing activity of ear mites, previously ruptured eardrum that has healed) or chronic infection disturbs this epithelial d FIGURE 13 Normal left eardrum in a dog. Note the tip of the malleus bone points migration process. When epithelial migration rostrally. is slowed, as with age or from disease, debris,

70 cliniciansbrief.com December 2016 d FIGURE 14 Wax plug (ceruminolith) on the eardrum d FIGURE 15 Tissue mass behind the eardrum. Note the malleus bone in the pars tensa, indicating the mass is behind the eardrum.

condition can look like a ceruminolith. The mucoid secretions dissolve in water and can be removed with a water or saline flush of the horizontal canal.

Because the normal pars tensa is translucent, the bulla cavity can be seen when enough light (using a video otoscope) transilluminates the bulla. In otitis media, fluid, if present, can be seen behind the eardrum in the form of bub- bles, blood, serum, or pus. Increasing pressure d FIGURE 16 Bulging eardrum caused by increased fluid from exudate accumulation can cause the pars pressure in the middle ear tensa to bulge outward. Both of these condi- tions result in marked pain; pressure must be cerumen, and hairs accumulate on the ear- relieved by myringotomy. Any tissue mass in drum. A ceruminolith may develop on the ear- the middle ear will obscure the ability to view drum on the external ear canal side (Figure the middle ear (Figure 15). Occasionally, in 14). These plugs may also consist of dried cats, a middle ear polyp can be seen through mucus or medication that has hardened in the the eardrum as a fleshy mass in the bulla. horizontal canal. The eardrum may be opaque from chronic Cerumen accumulation against the eardrum, inflammation and thickening and/or hyper- in addition to stenosis and hyperplasia, can keratosis. If the eardrum is opaque, the mid- impede conduction of sound waves and result dle ear cannot be evaluated visually from the in temporary hearing loss. Ceruminoliths ear canal. require mechanic removal, preferably with endoscopic grasping forceps through a video In some dogs, the pars flaccida of the eardrum otoscope with the patient anesthetized. If the may be bulging from fluid pressure in the mid- eardrum is not intact, exudates such as dle ear behind it (Figure 16) and may obscure mucus and pus can leak into the horizontal visualization of the pars tensa. Some have sug- canal and inspissate at the eardrum. This gested that this enlargement may be caused by

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7,8 degranulation of mast cells and resultant edema from atopic dermatitis. ( orfenicol, terbinane, mometasone furoate) This condition is frequently mistaken for a mass in the external canal and Otic Solution Antibacterial, antifungal, and anti-in ammatory should be closely evaluated. For Otic Use in Dogs Only The following information is a summary of the complete product information and is not comprehensive. Please refer to the approved In the Cavalier King Charles spaniel, a condition called primary secretory otitis product label for complete product information prior to use. media can cause bulging of the eardrum resulting from the failure of mucoid CAUTION: Federal (U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian. drainage from the tympanic bulla through the auditory tube. PRODUCT DESCRIPTION: CLARO® contains 16.6 mg/mL orfenicol, 14.8 mg/mL terbinane (equivalent to 16.6 mg/mL terbinane hydrochloride) and 2.2 mg/mL mometasone furoate. Inactive Cholesteatoma may be seen as a fleshy sac (epidermal cyst) at the level of the ingredients include puried water, propylene carbonate, propylene glycol, ethyl alcohol, and polyethylene glycol. eardrum associated with the invagination of squamous epithelium into the INDICATIONS: CLARO® is indicated for the treatment of otitis externa in dogs middle ear. In longstanding cases of otitis externa with otitis media, the ear- associated with susceptible strains of yeast (Malassezia drum may not be present at all; a direct communication of the external ear pachydermatis) and bacteria (Staphylococcus pseudintermedius). DOSAGE AND ADMINISTRATION: canal to the middle ear cavity may be noted. n CLARO® should be administered by veterinary personnel. Administration is one dose (1 dropperette) per aected ear. The duration of eect should last 30 days. Clean and dry the external ear canal before administering the product. Verify the tympanic membrane is intact prior to administration. Cleaning the ear after dosing may aect product eectiveness. Refer to product label for complete directions for use. References CONTRAINDICATIONS: 1. Scott DW, Miller WH, Griffin CE. Keratinization Ear Anatomy Do not use in dogs with known tympanic membrane perforation (see Otitis Externa: An Essential PRECAUTIONS). defects. In: Scott DW, Miller WH, Griffin CE. Harvey RG, Paterson S. CLARO® is contraindicated in dogs with known or suspected Muller and Kirk’s Small Animal Dermatology. Guide to Diagnosis and Treatment. Boca Raton, hypersensitivity to orfenicol, terbinane hydrochloride, or 6th ed. Philadephia, PA: Saunders Elsevier; FL: CRC Press; 2014:1-6. mometasone furoate, the inactive ingredients listed above, or similar 2001:1043-1045. Ear Disease drugs, or any ingredient in these medicines. 2. MacPhail C. Current treatment options for Gotthelf LN. Small Animal Ear Diseases: An WARNINGS: auricular hematomas. Vet Clin North Am Small Illustrated Guide. 2nd ed. St Louis, MO: Elsevier Human Warnings: Not for use in humans. Keep this and all drugs out Anim Pract. 2016;46(4):635-641. Saunders; 2004. of reach of children. In case of accidental ingestion by humans, contact a physician immediately. In case of accidental skin contact, 3. Harvey RG, Haar G. Ear, Nose and Throat Ear Margin Seborrhea wash area thoroughly with water. Avoid contact with eyes. Humans Diseases of the Dog and Cat. Boca Raton, FL: Ear margin seborrhea. Merck Manuals. http:// with known hypersensitivity to orfenicol, terbinane hydrochloride, CRC Press; 2016:30. www.merckvetmanual.com/mvm/eye_and_ or mometasone furoate should not handle this product. 4. Harvey RG, Harari J, Delauche AJ. Ear Disease ear/diseases_of_the_pinna/ear_margin_ PRECAUTIONS: of the Dog and Cat. Boca Raton, FL: CRC Press; seborrhea.html. Published October 2013. Do not administer orally. 2005:83. Accessed October 21, 2016. The use of CLARO® in dogs with perforated tympanic membranes has not been evaluated. The integrity of the tympanic membrane should 5. Little SE. August’s Consultations in Feline Fly Strike be conrmed before administering the product. Reevaluate the dog Internal Medicine. Vol 7. St Louis: Elsevier; Flies and mosquitoes of dogs. Merck Manuals. if hearing loss or signs of vestibular dysfunction are observed during 2016:323. http://www.merckvetmanual.com/pethealth/ treatment. dog_disorders_and_diseases/skin_ Use of topical otic corticosteroids has been associated with 6. Schick AE, Angus JC, Coyner KS. Variability disorders_of_dogs/flies_and_mosquitoes_ adrenocortical suppression and iatrogenic hyperadrenocorticism in of laboratory identification and antibiotic of_dogs.html. Published July 2011. Accessed dogs. susceptibility reporting of Pseudomonas spp October 21, 2016. Use with caution in dogs with impaired hepatic function. The safe isolates from dogs with chronic otitis externa. use of CLARO® in dogs used for breeding purposes, during pregnancy, Vet Dermatol. 2007;18(2):120-126. Mosquito Bite Hypersensitivity or in lactating bitches has not been evaluated. Allergy. Merck Manuals. http://www. 7. Eriksson PO, Hellström S. Degranulation of ADVERSE REACTIONS: merckvetmanual.com/mvm/eye_and_ear/ mast cells provokes a massive inflammatory In a eld study conducted in the United States, there were no directly diseases_of_the_pinna/allergy.html. attributable adverse reactions in 146 dogs administered CLARO®. reaction in the tympanic membrane. Published October 2013. Accessed October To report suspected adverse drug events and/or obtain a copy of the Laryngoscope. 111(7):1264-1270. 21, 2016. Safety Data Sheet (SDS) or for technical assistance, contact Bayer 8. Cole LK, Weisbrode SE, Smeak DD. Variation HealthCare at 1-800-422-9874. Otitis Media in gross and histological appearance of For additional information about adverse drug experience reporting Gotthelf LN. Diagnosis and treatment of otitis the canine pars flaccida. Vet Dermatol. for animal drugs, contact FDA at 1-888-FDA-VETS or online at media in dogs and cats. Vet Clin North Am http://www.fda.gov/AnimalVeterinary/SafetyHealth. 2007;18(6):464-468. Small Anim Pract. 2004;34(2):469-487. Pemphigus on the Pinna Gross TL, Ihrke PJ, Walder EJ. Pemphigus vulgaris. Suggested Reading NADA 141-440, Approved by FDA. Atopy & the Pinna In: Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Bayer, the Bayer Cross and CLARO are registered trademarks of Bayer. ©2016 Bayer HealthCare, LLC. Miller WH Jr, Griffin CE, Campbell KL. Muller and Skin Diseases of the Dog and Cat: Clinical and Histological Diagnosis. Oxford, UK: Blackwell Distributed by: Bayer HealthCare LLC, Animal Health Division, Shawnee Mission, Kirk’s Small Animal Dermatology. 7th ed. Kansas 66201 Elsevier Mosby; 2013:372. Science Ltd; 2005:32-35. Cerumen Pinnal Pedal Reflex Zachary JF, McGavin MD. Pathologic Basis of Mueller RS, Bettenay SV, Shipstone M. Value of the Veterinary Disease. 5th ed. St Louis, MO: pinnal-pedal reflex in the diagnosis of canine Elsevier Mosby; 2012:1171. scabies. Vet Rec. 2001;148(20):621-623. Cocker Ear Glands Harvey RG. Ear Diseases of the Dog and Cat. Boca Raton, FL: CRC Press; 2005:83.

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