Lecture 2 - Diseases of the Ear
Lecture 2 - Diseases of the Ear
I. ANATOMY OF THE EAR
A. Outer ear
1. The ear canal consists of the vertical and horizontal canals. The horizontal
canal terminates at the tympanic membrane (TM) which consists of the dorsal
pars flaccida (opaque, pinkish to white in color with superficial vessels) and
the ventral pars tensa (semi-transparent, glistening). The malleus (auditory
ossicle) can often be seen beneath the pars tensa.
2. The epidermis lining the ear canal contains hair follicles, sebaceous glands
and modified apocrine (ceruminous) glands that contribute to ear wax
(cerumen) production. Beneath the dermis and subcutis is the rolled cartilage
(auricular, annular) which supports the external ear canal.
B. Middle ear
1. The middle ear includes the tympanic membrane, tympanic cavity, tympanic
bulla, auditory ossicles (malleus, incus, and stapes), and auditory
(eustachian) tube which connects the tympanic cavity to nasopharynx.
2. The facial nerve along with branches of the sympathetic and parasympathetic
nerves course near the middle ear.
3. Function: air vibrations strike the TM and are transmitted to inner ear by
auditory ossicles. Stimulation of auditory receptors in inner ear results in the
perception of sound.
C. Inner ear (cochlea, vestibule, semi-circular canals): function in hearing
and balance.
From: Current Veterinary Dermatology: Griffin, Kwochka, MacDonald
Mosby 1993
OTITIS EXTERNA
II. General considerations
A. Incidence: otitis externa is common
Otitis externa occurs in about 15 - 20% of canine and 4 - 7% of feline cases
presented. The lower incidence in the cat is likely due to anatomical factors (more
erect ear, less hair, and shorter vertical canal).
B. Pathophysiology
1. Chronic inflammation results in hyperplasia of epidermis and apocrine glands,
dermal edema, and fibrosis. These changes cause swelling and stenosis of the
ear canal.
2. Long-standing chronic irritation can result in mineralization and subsequent
ossification of the annular and auricular cartilages (rock hard on palpation).
III. ETIOLOGY
A. Multifactorial disease process: predisposing, primary and perpetuating
factors
Predisposing factors change the microclimate in the ear and increase the risk of
disease, primary factors directly induce disease, and perpetuating factors tend to
complicate otitis and prevent resolution.
1. Predisposing factors: conformation of ear (droopy ears, etc.), excessive
moisture or hair in ear, treatment with irritating topical agents, tumors,
polyps, and underlying systemic disease.
2. Primary causes: parasites, dermatophytes, atopy, food allergy, contact
allergy, primary seborrhea, autoimmune disease, foreign bodies, glandular
hyperplasia,
3. Perpetuating factors: underlying otitis media, ear pathology (hyperplasia,
edema, fibrosis), bacteria, and yeast.
B. What's most common?
1. Cats frequently suffer otitis externa due to Otodectes cynotis and dogs often
due to underlying atopy, food allergy, or keratinization disorders.
2. Obtain a good history, examine the animal carefully and perform basic
diagnostic tests to identify likely predisposing, primary, and perpetuating
factors.
IV. DIAGNOSIS
A. History
Head shaking, aural pruritis, otic discharge, and malodor are common. Aural
hematomas may occasionally develop secondary to self-trauma/head shaking.
B. Physical exam
1. General exam: look for underlying diseases that predispose to otitis
*Q: What clues on physical exam are suggestive of underlying atopy? Food
allergy? Hypothyroidism? Keratinization defects? Demodex?
2. Appearance of otic discharge: may provide clues
A "coffee-grounds" appearance is suggestive of ear mites, a moist brown
exudate suggests yeast or Staph, oil yellow to tan discharge suggests
ceruminous otitis, and a purulent cream-yellow discharge suggests gram
negative bacteria.
C. Examination of the ear
1. Appearance of ear canal
a. The normal ear canal is pale to light pink in color and slightly moist
with cerumen. Some animals may have hairs in the vertical ear canal.
b. The ear canal becomes erythematous, swollen, and narrowed with
acute otitis. As inflammation continues, increased sebaceous gland
secretions, hyperplasia of the epidermis, and dermal edema occur.
Edema causes constriction of the canal lumen and pain from
entrapment of nerves against the cartilage.
c. With chronicity, proliferation of connective tissue in the dermis and
subcutis gives rise to fibrosis and additional thickening of skin. Further
occlusion of the ear canal occurs ("cauliflower ear") and ossification of
auditory cartilage may occur.
2. Otoscopic exam
a. Use aseptic cones soaked in cold sterile solution (rinse prior to use).
Examination of the inflamed ear is uncomfortable and painful - don't
hesitate to use adequate sedation or general anesthesia. It may be
necessary to treat firstto help alleviate swelling and pain and
facilitate adequate otoscopic exam.
b. Tympanic membrane (TM): may be difficult to visualize (one study
showed that a satisfactory view of the tympanic membrane in patients
with chronic otitis was only obtained in 28% of patients). Chronic otitis
externa inevitably gives rise to otitis media (see later).
D. Diagnostic evaluation
1. Samples of otic discharge
Obtain specimens from horizontal ear canal (place Q-tip through guarded
lumen of otoscope cone). Harvest samples from both ears.
a. Cytology: roll a small amount of discharge on glass slide, heat fix, and
stain (Diff-Quik). Evaluate for microorganisms (bacteria, yeast) and
inflammatory cells. *Q: Do dogs normally have microorganisms in
their ears? Yes, small numbers of yeast (Malassezia pachydermatis)
and gram positive cocci (Staph, Strep) are normal.
b. Oil smear: place small amount otic discharge on a slide and mix with
oil to look for Otodectes cynotis.
2. Pursue additional diagnostic tests as indicated
a. Unless underlying causes of otitis externa are addressed, treatment
will only temporarily ameliorate clinical signs.
b. Perform allergy testing, skin scrapings, DTM culture, endocrine testing,
etc. as indicated
i. Hypersensitivity (allergic) disease: is the most common cause
of persistent bilateral otitis externa in the dog. Up to 55% of dogs
with atopic dermatitis and 80% of dogs with food allergy have
concurrent otitis externa (and some will have just unilateral signs).
Otitis externa (pruritis or erythema of the ears) may be the
ONLY sign in 5% of atopic dogs and 25% of food allergic dogs.
ii. Keratinization defects and endocrinopathies: may see chronic
ceruminous otitis externa.
3. Other diagnostic tests
Culture/sensitivity is indicated in cases of chronic otitis externa and otitis
media/interna to help guide systemic antibiotic therapy (see later).
V. Treatment
A. General guidelines
1. Clean the ears first - topical medications are often ineffective in the face of
inflammatory exudate.
2. Sedation or general anesthesia is frequently required for exam and
treatment of an inflamed and painful ear. Treatment prior (with
glucocorticoids) helps alleviate inflammation and allows for a more effective
otoscopic exam.
3. If the integrity of the tympanic membrane is compromised, ruptured, or
unknown DO NOT use potentially ototoxic cleansing solutions or medications.
B. Glucocorticoids (GC's) (see table)
1. Systemic GC's (prednisone, prednisolone)
Indicated if inflammation, swelling, and stenosis of the ear canal are present.
Treatment helps to "open" the ear canal and allow for more effective topical
therapy. Dose: anti-inflammatory dose of oral prednisolone (0.5 - 1.5
mg/kg/day in the dog and 1 - 3 mg/kg/day in the cat) for 3 to 5 days.
2. Topical glucocorticoids: beneficial in most
Decreases inflammation, pain, swelling, pruritis, exudation, and proliferative
changes thus facilitating drainage and ventilation. Most topical otic
preparations contain steroids (see table).
C. Cleaning the ear
1. Remove excess hair. *Q: How would you do this?
Clippers can be used to gently remove excess hair at entrance to external ear
canal. Plucking hair from the vertical ear canal should only be performed if
hairs are thought to be directly contributory to otitis.
2. Cleansing solutions (see table)
a. Ceruminolytics: emulsify waxes and lipids so they can be flushed from
ear - helpful if excessive waxy secretions are present. Some products
are ototoxic (do not use with compromised TM).
b. Cleansing agents: mechanically flush away otic debris. Some have
antibacterial activity, anti-yeast activity, or drying effects. Many (such
as chlorhexidine) are potentially ototoxic. Solutions safe to use in face
of ruptured eardrum include sterile lukewarm 0.9% saline, DermaPet
Ear/Skin Cleanser, and acetic acid preparation (white vinegar diluted
1:1 with water).
c. Technique: BE VERY GENTLE as the TM is easily injured. *Q: What
complications may result from poor technique? A: Ruptured eardrum,
vestibular signs, Horner's and hearing loss.
i. In awake animal, fill ear canal with cleansing solution, massage
thoroughly, allow animal to shake head, and gently wipe away
dislodged debris.
ii. Anesthetized animal: gently infuse cleansing agent, massage ear
canal, and then suction using red rubber catheter attached to 12
ml syringe while observing through otoscope cone. An ear loop is
helpful for removing debris lodged near TM. The MedRx Video
Vetscope allows for magnified exam, flushing, and suctioning under
direct visualization.
iii. At home: have owners fill ear canal completely, massage base of
ears, let animal shake, and then wipe away loosened debris. Clean
ears once daily for 7 to 10 days; follow with once to twice weekly
maintenance cleaning. Monitor response to therapy with recheck
exam and cytology.
d. Drying agents: helpful in dogs susceptible to moist ears (swimmers,
etc.). Apply weekly to help facilitate evaporation.
VI. THERAPEUTICS FOR SPECIFIC DISEASES (SEE TABLE)
A. Bacterial otitis
1. Common pathogens include Staph intermedius (most common), Pseudomonas
aeruginosa, Proteus mirabilis, E. coli, Corynebacterium, and Streptococcus
spp. Multiple organisms are often present in cases of chronic otitis.
2. Cleansers: purulent discharge will inactivate many antibiotics, so ears must
be clean for effective therapy. Chlorhexidine, dilute povidone-iodine, or acetic
acid based flushes work well.
3. Topical antibiotics: products containing neomycin and polymxyin B, are
usually effective in uncomplicated cases while antibiotics with extended
spectrum (fluroquinolones, aminoglycosides) are used for more severe or
resistant cases. See otitis media (below) as well as table for listed antibiotics.
4. TrisEDTA: helpful in treatment of gram negative infections (such as
Psuedomonas). Promotes an alkaline pH (8.0) and facilitates increased
antibiotic efficacy.
5. Systemic antibiotics: indicated in cases of suppurative or chronic otitis, or
otitis media (see below).
B. Yeast otitis: usually due to Malassezia pachydermatis
1. Cleansers: acetic acid based solutions (DermaPet Ear/Skin Cleanser or white
vinegar/water) may effectively address yeast overgrowth.
2. Topical anti-yeast preparations: include 2% miconazole, clotrimazole, and
Tresaderm (containing thiabendazole). Baytril Otic (containing the antifungal
ingredient silver sulfadiazine) may also be used. Thiabendazole and silver
sulfadiazine are purportedly less efficacious.
3. Systemic agents: indicated in chronic refractory otitis externa or otitis media
(see later).
Malassezia pachydermatis
Otodectes cynatis
Diagrams from: Muller & Kirk's 5th edition.
C. Otodectes cynotis: ear mites
1. Overview
Ear mites are a common cause of otitis externa (50% of cases seen in the cat
and 5 - 10% of cases in the dog). Mites feed on lymph and epidermal debris,
inject mite antigen and induce host hypersensitivity reaction. As few as 2 - 3
mites can cause severe clinical signs. Mites may migrate to other areas of the
haircoat (important to treat entire body) and are highly contagious (treat all
in-contact dogs and cats). Treatment should continue for 4 weeks (to insure
complete therapy as not all products are effective against incubating mite
eggs).
2. *Topical otic preparations
Topical preparations include: Tresaderm (active ingredient - Thiabendazole),
Acarexx (active ingredient ivermectin), Milbemite (active ingredient
milbemycin) (latter two are licensed for use in cats), Cerumite (active
ingredient pyrethins), and Revolution (active ingredient selamectin). *Consult
package inserts for dosing instructions.
3. Topical body treatments
a. Revolution: treatment of choice. Safe, effective and labeled for
treatment of ear mites. Dosing regimen (labeled instructions): apply
once monthly for two treatments.
b. Systemic ivermectin: alternative therapy, not a first-line treatment
This drug is not labeled for this use. MUST test for heartworm
disease first, do NOT use in Collie breed or any crosses thereof, and
avoid use in animals < 4 months of age. Dosing regimen: 250 ug/kg
SQ: repeat every 10 - 14 days for 2 to 3 treatments.
D. Ticks
1. Otobius megnini: spinous ear tick
Found in the southwest United States. Parasitic larvae and nymphs feed
within ear causing a significant inflammatory reaction in the ear canal.
Treatment = removal of ticks, tick control measures (see later) and
management of secondary otic inflammation.
2. Other ticks (Dermacentor, Rhipicephalus sanguineus, etc): may also infest ear
canal.
Treatment involves symptomatic ear care, removal of ticks and control of
ticks on the body as well as in environment. Potential treatment options
include Preventic collar, Amitraz dips, Frontline, Advantix, and Revolution
(*consult package inserts for dosing instructions).
E. Other
1. Foreign bodies: remove and provide symptomatic ear care
Heavy sedation to general anesthesia may be necessary for removal. Alligator
forceps can be advanced through otoscope cone to aid in retrieval of foreign
bodies (such as grass awns).
2. Neoplasia: typically unilateral
a. Benign: nasopharyngeal polyps (cats). Usually arise from the mucosal
lining of the middle ear, Eustachian tube, or pharynx. Nasopharyngeal
polyps tend to extend through TM (causing signs of otitis) or into
nasopharynx (causing respiratory signs). Etiology unknown, and most
successfully managed via complete surgical excision (consult reference
source).
b. Malignant: ceruminous gland adenocarcinoma, squamous cell
carcinoma, other.
Ceruminous gland tumors are the most common ear canal tumor in
both the dog and cat.
OTITIS MEDIA/INTERNA
A. Etiology
1. Otitis externa
Otitis media usually results from chronic (> 45 - 60 days) otitis externa
(infection spreads across the tympanic membrane). Otitis media is present
in > 50% of dogs with chronic otitis externa.
2. Ascension via eustachian tube
In the cat, otitis media may also result from upper respiratory tract disease,
invasion of nasopharyngeal polyp across TM, or damage to the TM from ear
mites.
3. Microbes
Staph intermedius and Psuedomonas aeruginosa (as well as Strep, Proteus,
Klebsiella and E.coli). are common isolates in the dog. Staph intermedius,
Strep and Mycoplasma have been isolated in cats (as well as Psuedomonas
and others). Yeast otitis media is usually due to Malassezia pachydermatis.
B. Clinical signs
1. As for chronic otitis externa (otitis media is a major cause of recurrent otitis
externa).
2. Tympanic membrane: may be normal or abnormal
a. The TM may appear discolored, bulging, ruptured, absent, or normal.
In one study, 70% of eardrums in dogs with documented otitis media
were intact (eardrum can seal with infection trapped inside bullae).
b. Mucoid exudate in bulla or horizontal ear canal: produced by lining of
tympanic bulla and may be noted in horizontal ear canal when it leaks
through ruptured TM.
3. Cranial nerve signs: may note Horner's (damage to sympathetic supply),
facial nerve palsy (damage to facial nerve), or KCS (damage to
parasympathetic nerve supply to lacrimal gland).
4. Hearing deficits: may result from fluid accumulation in middle ear, damage to
auditory ossicles (osteomyelitis), or damage to the cochlear nerve.
5. Pain: may be noted on palpation of base of ear and some dogs may be
reluctant to open mouth.
6. Drainage of exudate from middle ear (via Eustachian tube) may give rise
pharyngeal signs.
7. Otitis interna: usually results from extension of otitis media
May note signs of peripheral vestibular disease (head tilt, nystagmus, circling)
due to damage of vestibulocochlear nerve. *Q: What type of nystagmus
would you expect to find in these patients?
C. Diagnostic evaluation
1. Preliminary workup as for otitis externa.
2. Cytology, culture/sensitivity from middle ear
a. General anesthesia is usually necessary
Prior treatment with systemic steroids (see above) may help facilitate
a more complete otoscopic exam. A cuffed endotracheal tube should
be placed to protect airway from drainage of secretions from middle
ear.
b. Obtain specimens for cytology and culture/sensitivity (C/S)
Obtain samples from middle ear (tympanic bulla) for culture and
sensitivity (C/S of horizontal canal may differ from C/S of bulla in up
to 80% of cases).
i. If eardrum is ruptured, gently advance sterile catheter (through
lumen of sterile otoscope cone) into tympanic bulla to obtain
diagnostic specimens.
ii. If eardrum is intact, perform myringotomy (consult reference
source) in region of pars tensa to obtain diagnostic specimens.
3. Bulla radiographs: look for soft tissue or bony changes
Perform radiographs before taking diagnostic specimens or infusing fluids.
Radiographic signs may not always be apparent in middle ear disease. CT and
MRI are more sensitive than radiographs in the detection of disease.
D. Treatment
1. General tenants of therapy as for otitis externa (see above and attached
table)
2. Flush tympanic bulla
If mucoid to purulent exudate is present within middle ear, you must flush
bulla to effectively treat (medications often ineffective in presence of
exudate). Flush with warmed non-ototoxic solution (such as sterile saline or
dilute povidone-iodine). After flushing, infuse bulla with non-ototoxic aqueous
topical medications (see below). May need to repeat treatment several times
to effect resolution of disease.
3. Topical medications (or infusions): avoid any preparations that are
potentially ototoxic
a. Topical antibiotic infusions into bullae enables very high levels of local
antibiotics to be attained at site of infection. Tris-EDTA may be helpful
for bacterial infections (see above).
b. Ototoxic preparations may result in hearing loss and vestibular signs.
Agents safe to instill in the middle ear include aqueous dexamethasone
sodium phosphate, ciprofloxacin, enrofloxacin, ofloxacin, aqueous
penicillin G, ticarcillin, some cephalosporins (ceftazidime), and the
antifungal agents clotrimazole, miconazole, and nystatin. Selection of
appropriate agents should be based on C/S results.
c. "Gemish" solutions: these homemade solutions are an alternate
therapeutic option for topical therapy of bacterial or yeast otitis
externa/media (but perform C/S if otitis media). They are not ototoxic
(safe to use in the face of a ruptured eardrum).
i. Bacterial Gemish: 12 mls DermaPet Ear/Skin Cleanser (+) 2 mls
injectable Baytril (22.7 mgs/ml) (+) 6 mgs dexamethasone sodium
phosphate.
ii. Malassezia Gemish: 12 mls DermaPet Ear/Skin Cleanser (+) 6 mgs
dexamethasone sodium phosphate.
Directions: apply 0.5 to 1.0 mls (depending on size of patient) to
affected ear twice daily for 14 days.
4. Systemic medications
a. Oral glucocorticoids: prednisone, prednisolone (see above) help to
alleviate inflammation (and hence open ear canal), as well as decrease
mucus production from the mucoperiosteum of middle ear.
b. Systemic antibiotics: select based on C/S results. Potential choices
include the fluoroquinolones (useful for rods) and Clavamox as well as
some cephalosporins (useful for cocci), and azithromycin (activity
against Mycoplasma and Bordetella in the cat). Therapy should be
continued for a minimum of 3 to 6 weeks and up to 6 months in some
cases. Use high end of dose range due to poor penetration into ear.
Systemic antifungals: oral ketonconazole or itraconazole are usually
effective for Malasezia.
5. Surgery (see below)
Cases unresponsive to medical therapy or those with severe proliferative
tissue require surgery for successful management (total ear canal ablation
with bulla osteotomy most successful).
VII. HOME CARE AND RECHECKS
A. Educate owner as to chronic nature of disease.
Many animals with otitis externa require continued ear care at home due to
persistence of predisposing factors (anatomy, moisture, underlying disease, etc.).
Otitis externa is often a manageable but not curable disease.
B. Demonstrate proper ear cleaning technique
You must take the time to explain the anatomy of the ear and demonstrate proper
cleaning technique so the owner understands.
In some cases, intermittent use of a cleansing/drying agent will suffice, in other
cases owners will need to utilize ceruminolytics and ear bulb flushes followed by
instillation of medication.
C. Advise owners to wipe away debris mobilized by ear cleaning with cotton
balls. Q-tips should be avoided as they are abrasive to the lining of the ear
canal and can drive debris further down.
D. Perform frequent rechecks to assess response to therapy and owner
compliance.
VIII. SURGICAL TREATMENT
A. Indications: chronic or severe cases of otitis.
Surgery is indicated in management of otitis media/externa when chronic changes
(fibrosis, ossification, stenosis of the ear canal), or patient uncooperation preclude
effective medical management.
B. Techniques
1. Lateral wall resection (Zepp): resection of lateral wall of ear canal.
In one study, surgery resulted in elimination of clinical signs in only 23% of
patients (as most often otic disease is not limited to vertical canal). Generally
believed to be ineffective.
2. Vertical ear canal ablation: resection of entire vertical ear canal.
Not effective if horizontal canal is diseased or if otitis media is present (and >
50% of patients with chronic otitis externa have otitis media). Does not allow
for drainage of infected middle ear.
3. Total ear canal ablation (TECA) with bulla osteotomy: most likely to be
effective.
The total ear canal and lateral wall of the tympanic bulla is removed.
Secretory tissue lining the bulla is removed by gentle curettage.
This procedure typically results in hearing loss (although loud noises may still
be appreciated via bone conduction).
Goals of Lecture 2 - Diseases of the ear
References (for all dermatology lectures): Muller & Kirk's Small Animal Dermatology
5th edition 1995. Kirk's Current Veterinary Therapy XII. Bonagura. W.B. Saunders
Co. 1996. WB Saunders Co. Selected excerpts from ACVIM 1995 and 1996
proceedings, and JAVMA, JIVM, and Compendium 1992-2006. Small Animal
Dermatology Secrets: Karen L. Campbell 2004. Skin Diseases of the Dog and Cat
Richard Harvey, Patrick McKeever 2003. Small Animal Dermatology A Color Atlas and
Therapeutic Guide Linda Medleau, Keith Hnilica 2001 and Small Animal Ear Diseases
An Illustrated Guide 2nd edition. Gotthelf 2005. Supplemental information also
provided courtesy of Dr. Danny Scott and Dr. Miller, Cornell University.
1. Be familiar with the basic anatomy of the ear (overview only) - what
constitutes outer ear? middle ear? inner ear? What important nerves course
near the region of the middle ear? (B.2.)
2. What happens to the ear in the patient that develops chronic otitis externa?
(II. B.). Is otitis externa usually due to a single cause? Be able to explain
(understand the "concept" of why otitis is multifactorial) (overview only III.A.) What are some of the more common inducers of otitis in the dog? In
the cat?
3. Be familiar (able to recognize) common historical complaints associated with
otitis. Why is it important to perform a physical exam? What clues may the
otic discharge afford? What are common changes noted on otoscopic exam?
4. Is it always possible to see the tympanic membrane on otoscopic exam? How
may treatment FIRST help insure a better otoscopic exam? What two
procedures should be routinely run on otic discharge specimens and what are
you looking for? (D.1.a.b.) When are additional diagnostic tests indicated?
(2.b.3.)
5. In regards to treatment, be familiar with approach to ear care, ear cleaning
and techniques utilized (section V. A.B.C.). Understand the general principals
of treatment for bacterial and yeast otitis (brief overview only). What
cleansing agents are particularly beneficial for yeast? When are systemic
antibiotics or systemic anti-fungal agents indicated?
6. Understand the basic tenants of treatment for the patient with ear mites (why
is it important to treat the ears, the patient and all in-contact animals?). Why
should most treatment regimens continue for 3 to 4 weeks?
7. What causes otitis media? (A.1.2.) What clinical signs may be present? (B.)
and how does diagnostic work-up differ from that of the patient with otitis
externa? (C.2.3.). What additional therapeutic strategies are often beneficial
in the management of otitis media? (D.2.3.4.). Why is it important to know
the impact of topical products on middle ear? (eg, ototoxicity)
8. Which surgery is typically most helpful for patients with chronic otitis externa
and media that fails to respond to medical therapy?
Tables below from: Western Veterinary Conference 2005 Otitis Externa II (V70)
Marcia Schwassmann, DVM, DACVD Veterinary Dermatology Center Maitland, FL,
USA
**The reader is advised to check all doses stated below in appropriate reference
source prior to use.
Ceruminolytic Otic Agents
Proprietary Name
Ingredients
Adams Pan-Otic
Purified water, isopropyl alcohol, aloe vera, diazolidinyl
urea, methylparaben, dioctyl sodium sulfosuccinate,
octoxynol, sodium lauryl sulfate,
parachlorometaxylenol, propylene glycol
ADL Ear Cleanser
Cocamidopropyl betaine, peg almond glycerides,
almond glycerides, isostearamidopropyl morpholine
lactate, salicylic acid, eucalyptol
Cerumene
25% squalene in isopropyl myristate liquid petrolatum
base
ClearX Ear Cleansing
Solution
6.5% dioctyl sodium sulfosuccinate, 6% urea peroxide
Corium-20
Purified water, SDA-40B 23%, glycerol
Earoxide Ear Cleanser
6.5% carbamide peroxide in a glycerin base
Otifoam
Water, cocamidopropyl betaine, PEG-60, almond
glycerides, mackalene 426, salicylic acid, oil of
eucalyptus
Cleaning/Drying Otic Agents
Proprietary Name
Ingredients
ADL Ear Flushing
Drying Lotion
Isopropyl alcohol, salicylic acid, eucalyptol, acetamide
MEA, propylene glycol, acetic acid, aluminum acetate,
hydrolyzed oat protein, wheat amino acids
Ace-Otic Cleanser
Acetic acid, lactic acid, salicylic acid in surface-active
vehicle containing docusate sodium and propylene
glycol
AloCetic
Acetic acid, aloe
Bur-Otic
Propylene glycol, water, burrow's solution, acetic acid,
benzalkonium chloride
ClearX Ear Drying
Solution
Acetic acid, colloidal sulfur, hydrocortisone
Chlorhexiderm Flush
Chlorhexidine gluconate
DermaPet Ear/Skin
Cleanser for Pets
Acetic acid, boric acid, surfactants
Epi-Otic Cleanser
2.5% lactic acid, 0.1% salicylic acid in docusate sodium
and propylene glycol base
Epi-Otic Cleanser with
Spherulites
Lactic acid and salicylic acid are present in
encapsulated and free forms, chitosanide is present in
encapsulated form, in docusate sodium and propylene
glycol base
Euclens Otic Cleanser
Propylene glycol, malic acid, benzoic acid, eucalyptus
oil
Fresh-Ear
De-ionized water, isopropyl alcohol, propylene glycol,
glycerin, fragrance, salicylic acid, PEG 75 lanolin oil,
lidocaine hydrochloride, boric acid, acetic acid
Gent-L-Clens
Lactic acid, salicylic acid in propylene glycol
Hexadene Flush
Water, propylene glycol, 0.25% chlorhexidine
gluconate, triclosan, fragrance
Nolvasan Otic
Special solvent, surfactant
Oticalm
Benzoic acid, malic acid, salicylic acid, oil of eucalyptus
Otic Clear
Deionized water, isopropyl alcohol propylene glycol,
glycerin fragrance, salicylic acid, PE 75 lanolin oil,
lidocaine hydrochloride, boric acid, acetic acid
Oti-clens
Propylene glycol, malic acid, bend acid, salicylic acid
OtiRinse
Water, Propylene glycol, SD Alcohol 40, DSS, Glycerin,
Nonoxynol-12, Salicylic acid, Lactic acid, Benzoic acid,
Benzyl Alcohol, Aloe Vera
Otocetic Solution
2% boric acid, 2% acetic acid, surfactants
Solvadry
2.7% boric acid, 90% isopropyl alcohol
Systemic antibiotics and antifungal agents for otitis
Antibiotic
Proprietary
Recommended
Name
Dosage
Amoxicillin trihydrate-Clavulanate Clavamox
potassium
14-22 mg/kg, ql2 h
Cefadroxil
Cefa-Tabs, CefaDrops
22 mg/kg, ql2 h
Cephalexin
Generics
22 mg/kg, ql2 h
Clindamycin hydrochloride
Antirobe
5.5-11 mg/kg, ql2 h
Difloxacin hydrochloride
Dicural
5-10 mg/kg, q24 h
Enrofloxacin
Baytril
5-20 mg/kg, q24 h
Itraconazole
Sporonox
5 mg/kg,q24h
Ketoconazole
Nizoral
5 mg/kg, ql2 h
Orbifloxacin
Orbax
2.5-7.5 mg/kg, q24h
Marbofloxacin
Zeniquin
2.5-5 mg/kg, q 24 h
Ormetoprim-sulfadimethoxine
Primor
55 mg/kg, q24 h, day 1,
then
27.5 mg/kg, q24 h
Trimethoprim-sulfadiazine
Tribrissen, Di-Trim 20-30 mg/kg, ql2 h
Trimethoprim-sulfamethoxazole
Generics
20-30 mg/kg, ql2 h
Topical Antimicrobial Otic Preparations
Proprietary Name
Ingredients
Conofite Lotion
Miconazole
Derma 4 Ointment
Nystatin, neomycin sulfate, thiostrepton, triamcinolone
acetonide
Dermagen Ointment
Nystatin, neomycin sulfate, thiostrepton, triamcinolone
acetonide
Dermalone Ointment
Nystatin, neomycin sulfate, thiostrepton, triamcinolone
acetonide
Forte-Topical
Hydrocortisone, neomycin sulfate, penicillin G procaine,
polymyxin B, chlorobutanol anhydrous
Gentocin Ophthalmic
Gentamicin sulfate
Gentocin Otic Solution
Gentamicin sulfate, betamethasone valerate
Liquichlor
Chloramphenicol, prednisolone, tetracaine, squalene
Otomax, DVMax
Gentamicin sulfate, betamethasone valerate,
clotrimazole
Panolog Cream and
Ointment
Nystatin, neomycin sulfate, thiostrepton, triamcinolone
acetonide
Quadritop Ointment
Nystatin, neomycin sulfate, thiostrepton, triamcinolone
acetonide
Topagen Ointment
Gentamicin sulfate, betamethasone valerate
Tresaderm
Thiabendazole, dexamethasone, neomycin sulfate
Tritop
Neomycin sulfate, isoflupredone acetate, tetracaine
hydrochloride
Veltrim
Clotrimazole
Additional Topical Therapy for Pseudomonas Otitis
Treatment
Preparation
Dosage
Injectable
enrofloxacin
1 part injectable enrofloxacin
(22.7 mg/ml) +
4 parts vehicle (saline, Synotic,
or hydrocortisone) = 4.5 mg/ml
5-10 drops/ear BID
Tris-EDTA
12g Tris buffer, 6.05 g EDTA, 1 L Fill ear 15 min prior to
distilled water, pH 8, autoclave
topical ab BID
15 min
Silver sulfadiazine 1:1 up to 1:50 mixed with water
1%
0.5 ml/ear BID
Polymyxin B or E
5-10 drops q 4-6 hr.
Ticarcillin(Ticar)
40 ml water into 3 gram vial
Acetic Acid (2.5
to 5%)
0.5-1 ml q 8 hr.
Fill ear canal 2-3 x daily;
needs > than 1 minute
contact times
Available Steroid Preparations
Proprietary Name
Ingredients
Bur-Otic HC
1% hydrocortisone, propylene glycol, water, burrow's
solution, acetic acid, benzalkonium chloride
ClearX Drying Solution Acetic acid, colloidal sulfur, hydrocortisone
Cort/Astrin Solution
Burrow's solution, 1% hydrocortisone
CortiSpray
1% hydrocortisone
Synotic Otic Solution
0.01% fluocinolone acetonide, 60% DMSO
Recommended Steroid Preparations for Bacterial Otitis
Topical Steroids
Oral Prednisone*
Mild infection
Hydrocortisone (12.5%)
Usually not necessary
Acute
Dexamethasone
(0.1%)
Chronic
Dexamethasone
(0.1%)
Triamcinolone
(0.1%)
Betamethasone
(0.1%)
May Be needed
Severe Infections
(Pseudomonas)
Hydrocortisone (12.5%)
May be necessary but use as low a
dose as short a time as possible
*Prednisone 1.1 to 2.2 mg/kg divided q12hr for 3 to 10 days stop as soon as possible