Canine otitis externa (outer ear infection and inflammation)
Outer ear infection, Ear infection in dogs, External otitis, Otitis externa, Chronic ear disease, Yeast ear infection, Malassezia otitis, Pseudomonas otitis, Otitis externa canina, Infección del oído externo, Infección de oídos en perros, Infección de oído en perros
Otitis externa means the outer ear canal is inflamed, and usually infected as well. It is one of the most common reasons dogs are seen by a vet. In the UK, where this has been measured most carefully in general practice, about 1 in 14 dogs is diagnosed with it in a single year; no comparable denominator-based figure exists for Colombia or Latin America, so treat that number as a UK measurement rather than a local one. It is painful and itchy, so dogs scratch, shake their head, and the ear often smells. The important part is this: an ear infection is almost always a symptom, not the whole story. In dogs who keep getting ear infections, the cause most often identified is an allergy, or an ear shape (long, hanging, or narrow ears) that traps moisture - though no primary-care study has measured what fraction of cases each cause accounts for. If only the infection is treated, it usually comes back. Treated properly, with the right ear medicine and by finding the cause, most dogs get better within a few weeks. SAFETY RULES THAT MATTER MORE THAN ANYTHING ELSE ON THIS PAGE. (1) Never give your dog human pain medicine. Ibuprofen, naproxen, aspirin and acetaminophen (paracetamol) are all dangerous to dogs - they cause stomach ulcers, bleeding, kidney failure and, with acetaminophen, liver and red-blood-cell damage. There is no safe home dose. A painful ear is a reason to call your vet the same day, not a reason to open the medicine cabinet. (2) Never give one animal another animal's medicine. Dog ear drops and dog NSAIDs must never go into or onto a cat - the approved dog ear products are labelled 'do not use in cats', and cats have been reported to develop wobbliness, a head tilt, a drooping third eyelid, deafness and a torn eardrum after dog ear drops were used on them. Never give a cat a dog NSAID. Do not use one dog's leftover ear medicine in another dog either: the right drug depends on what the vet saw under the microscope in that specific ear. (3) Nothing goes deeper into the ear than you can see. Do not use cotton buds or cotton-tipped applicators inside the canal - they pack wax and pus down against the eardrum and scrape the canal lining. Wipe only the part of the ear flap you can see. (4) Call before you change anything. If a dose is missed, if your dog shakes the medicine straight back out, if the ear looks worse, or if you are tempted to start cleaning, stop and phone the clinic first. Some of these products have specific rules - one of them tells you NOT to clean the ear at all for 45 days after the first dose - and cleaning or flushing an ear with a torn eardrum can cause permanent deafness. If your dog's ear was treated for ear mites, remember the mites are contagious: every other dog and cat in the house needs treating at the same time, or your dog will simply be re-infested.
What you might notice
- Scratching or rubbing at one or both ears, or rubbing the side of the head along furniture and the floor
- Shaking the head repeatedly, or holding it tilted slightly to one side
- A smell coming from the ear - often described as yeasty, sour or musty
- Brown, black, waxy or yellow discharge in the ear, sometimes flecked onto the fur or bedding
- Redness, swelling or a thickened, leathery feel to the inside of the ear flap and the opening of the canal
- Flinching, yelping or pulling away when the ear is touched or the head is stroked
- Suddenly not wanting the collar, harness or head touched, or becoming grumpy when handled
- Ear problems that clear up on medicine and then come back within weeks or months - this pattern is itself a sign, and usually points to an allergy underneath
- Only ever one ear, over and over, in a middle-aged or older dog - a persistently one-sided ear is a reason to look for a growth, a polyp or a grass seed, not a reason to keep refilling drops
- Other dogs or cats in the house scratching their ears too - ear mites are contagious, so a household pattern points at mites rather than at an allergy
Standard of care
Otoscopy, tympanic membrane assessment and ear cytology before any drug is dispensed
Approved / guideline-backedExamine both canals, confirm the tympanic membrane is intact, and take a stained smear from each affected ear. Cytology separates cocci from rods from Malassezia and tells you which approved product is appropriate. Membrane status is not a soft preference: the labels of Osurnia, Claro, Mometamax Single, Easotic and Posatex all state 'Do not use in dogs with known tympanic membrane perforation', and Otomax and Mometamax instruct that before instilling any medication the external ear canal must be examined thoroughly to be certain the tympanic membrane is not ruptured, in order to avoid transmitting infection to the middle ear as well as damaging the cochlea or vestibular apparatus. Baytril Otic states that use in dogs with perforated membranes has not been evaluated. Record OTIS3 so the recheck is a measurement.
Named products: No drug at this step - this is the diagnostic gate that the approved labels require
Every FDA-approved in-clinic canine otic product carries an organism-specific indication and a labelled instruction to verify tympanic membrane integrity before administration (Osurnia, Claro and Mometamax Single labels, verified on DailyMed). The OTIS3 index was developed in 115 dogs (55 healthy, 60 affected): total score >=4 separated affected from healthy ears with 91.1% sensitivity and 100% specificity, and intra/interobserver reliability was high (ICC >0.95, Cohen's kappa >0.65). Its authors published it as a pilot study and concluded it was suitable for further validation by a larger group of clinicians; later investigators have used it as a primary endpoint and one has described it as validated, so the honest description is a reliability-tested index in wide trial use rather than a formally validated instrument. A US point-prevalence study of 22 dermatology referral practices (550 animals: 479 dogs, 71 cats) found cytology was performed in 86.3% of conditions treated with antimicrobials but bacterial culture in only 15.3%.
FDA-approved topical combination otic therapy, matched to cytology
Approved / guideline-backedTopical therapy is the treatment of otitis externa. Approved canine combinations pair an antibacterial, an antifungal and a corticosteroid. Long-acting in-clinic formulations remove owner-compliance failure, which is a major cause of treatment failure; owner-applied products remain appropriate where daily dosing is realistic and where a broader or different antibacterial spectrum is needed. Match the product to the labelled organism, and read the label's own safety text before dispensing: all eight of these products are contraindicated or explicitly cautioned against where the tympanic membrane is perforated; the four gentamicin-containing products (Otomax, Mometamax, Easotic, Mometamax Single) sit behind a labelled deafness warning; and Claro's own label states that Claro has been associated with rupture of the tympanic membrane.
Named products: Verified FDA-approved canine otic products, NADA numbers and labelled indications taken from the FDA-approved labels retrieved on DailyMed: Osurnia, florfenicol/terbinafine/betamethasone acetate gel, NADA 141-437 (Dechra) - Malassezia pachydermatis and Staphylococcus pseudintermedius; Claro, florfenicol/terbinafine/mometasone furoate solution, NADA 141-440 (Elanco) - Malassezia pachydermatis and Staphylococcus pseudintermedius; Mometamax Single, gentamicin/posaconazole/mometasone furoate suspension, NADA 141-600 (Merck Animal Health) - Malassezia pachydermatis, Staphylococcus pseudintermedius and Pseudomonas aeruginosa; Easotic, hydrocortisone aceponate/miconazole nitrate/gentamicin sulfate suspension, NADA 141-330 (Virbac) - Malassezia pachydermatis and Staphylococcus pseudintermedius; Otomax, gentamicin sulfate/betamethasone valerate/clotrimazole ointment, NADA 140-896 - Malassezia pachydermatis and bacteria susceptible to gentamicin, with Pseudomonas aeruginosa named in the label's microbiology section; Mometamax, gentamicin sulfate/mometasone furoate/clotrimazole suspension, NADA 141-177 - Malassezia pachydermatis plus Pseudomonas spp. including P. aeruginosa, coagulase-positive staphylococci, Enterococcus faecalis, Proteus mirabilis and beta-haemolytic streptococci; Posatex, orbifloxacin/mometasone furoate/posaconazole suspension, NADA 141-266 - Malassezia pachydermatis plus coagulase-positive staphylococci, Pseudomonas aeruginosa and Enterococcus faecalis; Baytril Otic, enrofloxacin/silver sulfadiazine emulsion, NADA 141-176 (Elanco) - Malassezia pachydermatis, coagulase-positive Staphylococcus spp., Pseudomonas aeruginosa, Enterobacter spp., Proteus mirabilis, Streptococci spp., Aeromonas hydrophila, Aspergillus spp., Klebsiella pneumoniae and Candida albicans. PSEUDOMONAS, STATED PRECISELY: of the three long-acting in-clinic products, only Mometamax Single names Pseudomonas aeruginosa in its labelled indication (Osurnia and Claro do not). Among the owner-applied products, Posatex, Mometamax and Baytril Otic all name Pseudomonas in the labelled indication, and Otomax names P. aeruginosa in its microbiology section. A clinician with rods or Pseudomonas on cytology therefore has more than one approved option. All eight are for otic use in dogs only; the labels of Osurnia, Claro and Mometamax Single say 'Do not use in cats'. AGE, WEIGHT AND REPRODUCTIVE LIMITS ON THESE LABELS: none of the eight labels reviewed states a minimum age or minimum body weight, but Posatex, Otomax and Mometamax are dosed in weight bands (4 drops daily for dogs under 30 lb, 8 drops for dogs 30 lb and over - check the individual label), and safe use in dogs used for breeding, during pregnancy or in lactating bitches has not been evaluated for Osurnia, Claro, Mometamax Single, Easotic, Posatex or Baytril Otic. Otomax and Mometamax instead carry corticosteroid teratogenicity precautions (see the safety section). Baytril Otic and Posatex both contain a fluoroquinolone, a class associated with cartilage erosions and arthropathy in immature animals.
Three in-species randomised registration trials support the long-acting products. Osurnia (florfenicol/terbinafine/betamethasone acetate gel, two doses 7 days apart) vs vehicle placebo in 284 dogs: treatment success 64.78% vs 43.42% at day 45 (Forster 2018, Elanco-authored). Hearing honesty matters here: no hearing loss occurred in that 284-dog trial, but hearing was assessed by a subjective 'clap test' rather than by audiometry, and deafness and hearing decrease/loss are reported post-approval adverse events on the Osurnia label, which directs the clinician to re-evaluate the dog if hearing loss or signs of vestibular dysfunction are observed during treatment. Claro (florfenicol/terbinafine/mometasone furoate, single dose) in a multicentre masked randomised field study of 221 dogs: success 72.5% vs 11.1% control at day 30 (Blake 2017, Bayer Animal Health-authored). Gentamicin/posaconazole/mometasone furoate single dose in 316 dogs was non-inferior to the two-dose florfenicol gel: 89.5% (128/143) vs 87.2% (116/133) success at day 28 (Heuer 2024, MSD Animal Health-authored; the trial product is labelled Mometamax Ultra in that report and marketed in the US as Mometamax Single). A separate 286-dog single-blinded randomised study found the two-dose gel and a hydrocortisone aceponate/miconazole/gentamicin suspension given daily for 5 days equivalent, OTIS-3 falling 63-64% by day 28, with recurrence at day 56 in 11% of both groups (King 2018, Elanco-authored). SPONSORSHIP DISCLOSURE: all four of those trials were authored by the marketing authorisation holder or its animal-health division. Note the further limits: none of these trials enrolled chronic end-stage disease, Heuer 2024 states that efficacy in chronic otitis externa was not investigated and that cytology was not used to aid diagnosis or to identify secondary pathogens, and none was powered for the rare ototoxic outcomes the labels report.
Find and treat the primary cause - this is what stops recurrence
Approved / guideline-backedRecurrent otitis externa is most often allergic skin disease presenting in the ear. Treating each flare without addressing the underlying disease guarantees the next flare. Work the allergic cause: flea control, a properly conducted elimination diet trial where a food reaction is plausible, and long-term control of atopic dermatitis. Where conformation is the driver (pendulous or narrow V-shaped drop ears, hair-filled canals), the honest intervention is structural and preventive management, not more medication. Where Otodectes cynotis is found, treat every in-contact dog and cat in the household at the same time; the mite is contagious and treating one animal alone produces reinfestation that is then mistaken for treatment failure.
Named products: For the underlying allergic disease, per ICADA 2015: allergen-specific immunotherapy (the only disease-modifying option), oclacitinib, ciclosporin (modified, oral), topical and oral glucocorticoids. Lokivetmab (Cytopoint) is licensed for pruritus associated with atopic/allergic dermatitis by the USDA APHIS Center for Veterinary Biologics, not by FDA CVM - do not describe it as FDA-approved. None of these products carries an otitis externa indication. They treat the allergy, not the ear infection. Adding oral or topical body glucocorticoids on top of a steroid-containing ear product stacks corticosteroid exposure; see the safety section before doing so, and never in an unmonitored diabetic dog.
The ICADA 2015 guideline states that only two interventions are likely to prevent or delay recurrence of atopic flares: allergen-specific immunotherapy, and proactive intermittent topical glucocorticoid application. Mechanistic support in the ear specifically: ear canals of atopic dogs with mild non-infectious otitis had significantly lower concentrations of beta-defensin (cBD3-like, p = 0.0007) and cathelicidin (p = 0.049) host defence peptides than healthy dogs (Santoro 2023; 10 healthy and 20 atopic dogs; the same study found no consistent antimicrobial activity in aural secretions from either group, so this is a mechanism finding, not a treatment target). Conformation: compared with breeds with erect ear carriage, breeds with pendulous ear carriage had 1.76 times the odds and breeds with V-shaped drop ears 1.84 times the odds of otitis externa. Honest limit on the aetiology claim: neither ICADA 2015 nor Santoro 2023 nor the VetCompass prevalence work reports what proportion of canine otitis is allergic in origin. 'Most often identified' reflects referral-population dermatology practice, not a measured aetiologic fraction.
Antimicrobial stewardship: keep therapy topical, culture before going systemic
Controlled trial in this speciesOtitis externa is a surface disease that topical drugs reach at concentrations systemic antibiotics cannot approach. Reserve systemic antibacterials for confirmed deep or middle-ear involvement, and then only on culture and susceptibility. Multidrug resistance in this exact clinical niche is already common, and prescribing habit is a measurable contributor.
Named products: No systemic antibiotic is FDA-approved for canine otitis externa; any systemic use is extra-label and requires a valid veterinary-client-patient relationship under 21 CFR Part 530
In 142 cases of small-animal external otitis (138 dogs, 4 cats), multidrug resistance was observed in almost 50% of isolates. In a US dermatology referral point-prevalence study (550 animals at 22 practices), antimicrobials were prescribed in 54.9% of cases, third-generation cephalosporins made up 43.9% (54/123) of systemic antibiotics given to dogs, and bacterial culture was used in only 15.3% of cases - the authors identify reducing broad-spectrum systemic use in favour of topical therapy, and the need for narrow-spectrum topical options, as the improvement opportunity.
Ear cleaning - useful, but do not oversell it, and follow the product label
Controlled trial in this speciesCleaning removes debris and biofilm and is standard practice, but the in-species evidence for added benefit on outcome is weaker than the practice's popularity suggests. It appears to matter most when rod-shaped bacteria are present. Three label-driven rules govern it. First, cleaning must follow the label of the medication used: approved products instruct cleaning and drying the canal before the first dose, and the Osurnia label instructs NOT to clean the canal for 45 days after the initial administration so the gel stays in contact with the canal - which means that if the ear worsens inside those 45 days the owner must return to the clinic rather than start cleaning or flushing, and if alternative otic therapy becomes necessary the ear is cleaned first as a veterinary decision, not a home one. Second, owners must never push cotton-tipped applicators into the canal; they pack debris inward against the tympanic membrane and traumatise the canal epithelium. Wiping the visible pinna is the limit of home cleaning unless the clinic has specifically taught a filling-and-massage technique with a named product. Third, no cleaner or flush goes into an ear whose tympanic membrane has not been seen and confirmed intact, because solution reaching the middle ear can cause deafness and vestibular injury.
Named products: Cleaning solutions are not approved animal drugs; hypochlorous acid and commercial ceruminolytic cleaners are the products with in-species trial data. Note that some widely used ceruminolytic and antiseptic ingredients have been reported as ototoxic when they reach the middle ear, which is why membrane integrity gates their use.
In a randomised split-ear study of 23 dogs (40 ears), manual cleaning with a commercial product versus a dry or saline-moistened gauze wipe produced no statistically significant difference in cytological score, modified OTIS3, pruritus VAS or owner assessment at day 7; both groups improved, and only cleaned ears showed a significant fall in cytological rod scores. In a separate split-ear study of 20 dogs with chronic otitis, an anaesthetised hypochlorous acid flush was a suitable cleaning solution but produced no outcome advantage over saline flush plus a commercial ear cleaner, and no adverse effects or hearing changes were detected - that study performed hearing tests before and after flushing precisely because ototoxicity is the recognised hazard of the procedure.
Anaesthetised video-otoscopic lavage for obstructed, chronic or painful canals
Early evidenceA canal packed with exudate or ceruminous debris cannot be examined, cannot be cytologically sampled properly, and cannot be reached by topical drug. Anaesthetised flushing with video-otoscopy also allows the tympanic membrane to be seen, foreign bodies and polyps to be found, and middle-ear sampling where indicated. SAFETY GATE: the tympanic membrane must be assessed before and during the procedure. Flushing solution that passes a ruptured or never-visualised membrane into the middle ear can cause deafness and vestibular injury, so the flush is a staged procedure under visualisation, not a blind irrigation, and hearing and vestibular function should be checked before and after. If a perforation is found, the fluid and any medication plan change - the approved otic products are contraindicated or unevaluated in that ear.
Named products: None - procedural
Chronic canine otitis externa frequently requires anaesthetised ear flushing; in a 20-dog split-ear study of anaesthetised flushing, hearing testing before and after showed no difference between hypochlorous acid and saline flushing and no adverse effects were seen. That trial tested hearing because middle-ear exposure during flushing is the known risk. This is procedural standard practice supported by clinical trial context rather than by a dedicated controlled trial of the procedure itself.
Surgery for chronic and end-stage disease
Early evidenceWhen the canal has become permanently stenotic, calcified or proliferative, no topical or systemic drug reverses those structural changes. Surgery is the definitive option at that point. Lateral ear canal resection is the earlier, lower-morbidity operation; total ear canal ablation with lateral bulla osteotomy is the salvage procedure and carries a high complication rate that must be disclosed before consent.
Named products: None - surgical
A retrospective descriptive series of lateral ear canal resection in 40 dogs (58 ears) by a single non-specialist surgeon at one primary-care facility, median follow-up 952 days (IQR 589.5-1617): no ear progressed to end-stage disease or required conversion to total ear canal ablation, no serious postoperative complications, median annual ear-cleaning frequency fell from 6.74 to 1.58 and median pruritus score from 100% to 20%. Retrospective, uncontrolled, single surgeon, single practice, no predefined staging criteria - it cannot establish superiority over anything. For total ear canal ablation with lateral bulla osteotomy in 57 dogs (79 ears): complications occurred in 64.1% of unilateral and 72.5% of bilateral single-stage ears, including facial nerve complications in 33.3% and 40.0% respectively - single-stage bilateral surgery was not riskier than unilateral, but the absolute complication burden is substantial. No study in this literature randomises surgery against any drug, injected or topical, so no comparative-superiority claim can be made from it.
Non-standard approaches: what has been studied, and how weakly
Early evidenceFour non-standard topical approaches appear in the peer-reviewed literature for this condition. Two have randomised in-species trials in affected dogs; one has engraftment data in healthy dogs only; one is in vitro only and has never been given to a live animal for this condition. None is an FDA-approved animal drug and none replaces the steps above. They are listed here so that clinicians and owners who encounter them online see them placed accurately rather than either hyped or dismissed. SPONSORSHIP DISCLOSURE: of these four, the probiotic study (item 3) is authored by staff of the marketing company Ecuphar Veterinaria SLU (Animalcare Group) together with Yun NV, the developer of the YUN-V2.0 and YUN-S1.0 strains tested - that is manufacturer authorship of the study of the manufacturer's own product. The other three are from academic institutions, though item 1 evaluates a commercial formulation.
Named products: None of these is an FDA-approved animal drug. In the US they would be unapproved new animal drugs if marketed with therapeutic claims.
1) RANDOMISED, IN AFFECTED DOGS. An antibiotic-free topical ear solution containing antimicrobial peptides plus encapsulated chamomile, calendula, rosemary and hops extracts was compared with gentamicin/betamethasone valerate/clotrimazole in a 4-week randomised study of 40 dogs: OTIS-3 and pruritus VAS scores were comparable between arms, with no adverse drug reactions in the test arm versus one in the conventional arm. Small, single-centre, not blinded, and 'comparable' in a 40-dog study is not demonstrated equivalence. Important class distinction: these are antimicrobial host-defence peptides, an entirely different class from regenerative peptides such as BPC-157 or TB-500. 2) RANDOMISED, IN AFFECTED DOGS. An LED-illuminated chromophore gel in 64 dogs randomised to gel once weekly (n=21), gel twice weekly (n=23), or enrofloxacin/silver sulfadiazine twice daily (n=20): all three arms improved; the twice-weekly gel arm achieved the largest clinical score reduction, with no between-group difference in bacterial CFU reduction. 3) HEALTHY DOGS ONLY, NO EFFICACY ENDPOINT. Probiotic ear drops containing live Lactiplantibacillus plantarum YUN-V2.0 and Lacticaseibacillus rhamnosus YUN-S1.0 were given to 15 HEALTHY dogs randomised into five groups of three; Lactobacillaceae rose significantly at 24 hours and persisted at one week, and the drops inhibited otitis pathogens on in vitro disk testing. No affected dogs were enrolled and no clinical efficacy endpoint was measured. 4) IN VITRO ONLY, NEVER GIVEN TO A LIVE ANIMAL FOR THIS CONDITION. NCP-3 is Naja Cardiotoxin Peptide-3, a peptide derived from cardiotoxin 1 of the Chinese cobra (Naja atra) - that is, from a snake-venom cardiotoxin. Tested in the laboratory against clinical isolates from dogs with otitis externa, it was bactericidal against Staphylococcus pseudintermedius (MBC50 3.1 ug/mL, MBC90 6.3 ug/mL) and reached MBC50 12.5 ug/mL against Pseudomonadaceae, but neither MBC50 nor MBC90 was achieved against Enterobacteriaceae or Malassezia pachydermatis, and it was ineffective against the Proteus mirabilis reference strain. No animals were treated.
No otitis externa-specific consensus guideline was located. The closest applicable published guideline addresses the primary cause most often identified: ICADA 2015 updated guidelines for the treatment of canine atopic dermatitis. Its most transferable statement for ear disease is that only two interventions are likely to prevent or delay recurrence of flares - allergen-specific immunotherapy, and proactive intermittent topical glucocorticoid application. — International Committee on Allergic Diseases of Animals (ICADA)
How it is diagnosed
- Full history including itch elsewhere on the body, seasonality, diet, previous ear episodes and what was used - the pattern of recurrence is the single most useful diagnostic clue to a primary allergic cause
- Otoscopic examination of both ear canals, and explicit assessment of whether the tympanic membrane is intact - every FDA-approved in-clinic otic product requires this before administration, and the approved products are contraindicated where the membrane is known to be perforated
- Ear cytology from each affected canal (stained smear): cocci, rod-shaped bacteria, Malassezia and neutrophils are differentiated, and this - not the smell or the appearance - directs the choice of topical drug
- Record a baseline objective score (Otitis Index Score, OTIS3: erythema, oedema/swelling, erosion/ulceration, exudate, each 0-3) plus a pruritus and pain score, so response can be measured rather than guessed. OTIS3 was published as a pilot instrument that its own authors said was suitable for further validation by a larger group of clinicians; it has since been adopted as the primary or key endpoint in several registration and academic trials, which is the practical case for using it.
- Bacterial culture and susceptibility reserved for rod-shaped bacteria on cytology, treatment failure, or before any systemic antimicrobial - not for routine first episodes
- Sedation or general anaesthesia with video-otoscopy and canal lavage where the canal is stenotic, obstructed with debris, or too painful to examine properly
- Identify and name the PRIMARY cause: allergic skin disease (atopic dermatitis or cutaneous adverse food reaction) most commonly identified, then Otodectes cynotis, foreign body, keratinisation or endocrine disease, aural mass or polyp, and ear-carriage conformation. Where Otodectes is found, treat every in-contact dog and cat in the household simultaneously - the mite is directly contagious and treating the index animal alone leads to reinfestation.
- For chronic, unilateral, proliferative or non-responsive disease, or suspected middle-ear involvement: advanced imaging (CT or MRI), biopsy of any mass, and referral to a dermatologist or surgeon
- Recheck with repeat cytology before declaring resolution and stopping therapy - clinical appearance alone over-estimates cure
Where a biologic fits
Our own product, graded by the same rule
There is no legitimate role for mesenchymal stem cell, exosome or regenerative-peptide products in canine otitis externa: no clinical efficacy study of any design has been published in this condition in any species, the only live-animal ear study of such a product measured epithelial migration on the normal eardrums of four healthy beagles, and the treatments that do work - cytology-directed topical therapy with an FDA-approved otic product, control of the underlying allergic or structural cause, and surgery for end-stage canals - are all conventional.
What exists
Nothing in this condition. PubMed searches combining otitis with mesenchymal stem cell, mesenchymal stromal cell, exosome, extracellular vesicle or secretome in dogs or cats return zero clinical studies. There is no published trial, no case series, and no case report of an MSC, exosome/EV or regenerative-peptide product used to treat canine otitis externa. THE ONE LIVE-ANIMAL EAR STUDY THAT DOES EXIST, stated plainly so nobody can present it as a discovery: canine adipose-derived MSC conditioned media was applied weekly, three times, to the tympanic membrane of one ear in four normal beagles, with the other ear untreated; epithelial migration rate was faster in the treated ears (p<0.05) and no adverse events were recorded (Suh H, Kim S, Oh T, Bae S. Vet Sci. 2022;9(2):69. PMID 35202322. DOI 10.3390/vetsci9020069). That is four healthy dogs, a surrogate endpoint (ink-drop migration on a normal eardrum), conditioned media rather than a characterised exosome product, and no ear disease of any kind. It does not show that any biologic treats otitis externa, and it must not be cited as if it did. The nearest adjacent disease evidence is in canine ATOPIC DERMATITIS, the primary cause most often identified in recurrent otitis - and even that evidence does not measure ear disease. It consists of: one double-blinded placebo-controlled trial of allogeneic canine adipose MSC in dogs, in which high-dose MSC significantly lowered owner-scored pruritus VAS and serum miR-483 versus placebo at day 90, but the veterinarian-scored lesion index CADESI-4 showed only non-significant downward trends and the per-arm sample size was not published (Kaur 2021, DOI 10.1007/s11259-021-09853-9); one fully null prospective pilot of autologous adipose MSC, whose authors reported the cells did not significantly reduce clinical signs or owner-assessed pruritus (Hall 2010, PMID 20957613); and two uncontrolled open-label series, n=26 (DOI 10.1136/vr.104867) and n=16 (DOI 10.5455/javar.2020.g453). Exosome evidence in canine atopic dermatitis is a 6-beagle pilot with 2 dogs per arm (DOI 10.3390/ani14020282) - hypothesis-generating only. Most of the wider canine atopic dermatitis MSC literature is mouse-model work using canine cells and is rodent evidence, not dog evidence. For peptides: no peptide in the MicroAmino class has controlled efficacy evidence in dogs, cats or horses; the only BPC-157 work involving dogs is a pharmacokinetic study in rats and beagles reporting an elimination half-life under 30 minutes and 45-51% intramuscular bioavailability in beagles (PMID 36588717), which is a PK result and not an efficacy result; TB-500 has essentially nothing in companion animals and is FEI-banned. There is genuine in-species peptide work in this condition, but it is a different class of molecule - antimicrobial host-defence peptides, studied as topical antibacterials, including a 40-dog randomised comparison against a conventional gentamicin combination (PMID 41305350) and in vitro activity of the snake-venom-cardiotoxin-derived NCP-3 against canine otitis isolates (PMID 42176132). Presenting that literature as support for a regenerative peptide would be a substitution of one drug class for another.
What has not been shown
There is no published in-vivo clinical efficacy evidence for exosome or extracellular-vesicle products in dogs or cats for any indication, let alone for ear disease. There is no MSC study of any design in dogs or cats with otitis externa. There is no evidence that any biologic reduces otitis recurrence, shortens an ear flare, reverses canal stenosis, restores hearing, spares corticosteroid, or substitutes for topical antimicrobial therapy or for surgery in end-stage disease. The single live-animal ear study of a cell-derived product (Suh 2022, four healthy beagles, conditioned media, epithelial migration on a normal tympanic membrane) is not an efficacy study in ear disease and does not change any of that. The one authorised veterinary MSC product, DogStem (authorised by the EUROPEAN MEDICINES AGENCY, EMEA/V/C/005829; EU marketing authorisation EU/2/22/285; separately authorised in Great Britain as Vm 55127/5000), is authorised for canine osteoarthritis only - it uses EQUINE umbilical-cord MSCs in DOGS, a xenogeneic product, and its EPAR/SmPC reports that in the pivotal field trial 51% of DogStem-treated dogs versus 5% of placebo-treated dogs met the treatment-success endpoint at 8 weeks, decaying to 39% versus 11% at 12 weeks. That is a joint endpoint, from an EU authorisation. It says nothing about ears, and DogStem is not FDA-approved - there is no FDA CVM approval for it or for any animal cell product. The supporting canine RCT is Punzon 2022 (n=80 dogs with naturally occurring elbow or hip osteoarthritis, PMID 36198051). Claims that these products are immune-privileged, immune-invisible or free of immune reaction are not defensible: Punzon 2023 found that BOTH equine and canine MSCs generated antibody titres in dogs, although no adverse events were detected and safety was judged acceptable (Front Vet Sci. 2023;10:1098029, PMID 37266387); the DogStem laboratory data likewise record anti-xenogeneic-MSC antibodies in treated dogs. 'Immune-privileged' and 'zero-flare' are therefore banned descriptions. And in the United States no animal cell, stem cell or exosome product is FDA-approved; marketed with therapeutic claims they are unapproved new animal drugs.
Sources
- No MSC/exosome/secretome literature exists in canine or feline otitis - PubMed search returning zero results — PubMed query: (mesenchymal stromal cell OR exosome OR secretome) AND otitis AND (dog OR canine OR feline) - 0 records, searched 12 September 2026. Reported per PubMed attribution requirements. Note that this query does not retrieve Suh 2022 (tympanic membrane in healthy beagles, indexed without 'otitis'), which is cited separately below; the zero result is a statement about otitis literature, not about all ear literature. https://pubmed.ncbi.nlm.nih.gov/?term=%28mesenchymal+stromal+cel
- The only live-animal ear study of a cell-derived product - four HEALTHY beagles, surrogate endpoint, not otitis — Suh H, Kim S, Oh T, Bae S. Canine Stem Cell Conditioned Media Accelerates Epithelial Migration in the Canine Tympanic Membrane. Vet Sci. 2022;9(2):69. PMID 35202322. DOI 10.3390/vetsci9020069 https://pubmed.ncbi.nlm.nih.gov/35202322/
- The one blinded placebo-controlled MSC trial in the adjacent condition (canine atopic dermatitis) - positive on itch, not on lesions — Kaur G, Ramirez A, Xie C, Clark D, et al. A double-blinded placebo-controlled evaluation of adipose-derived mesenchymal stem cells in treatment of canine atopic dermatitis. Vet Res Commun. 2021. DOI 10.1007/s11259-021-09853-9 https://doi.org/10.1007/s11259-021-09853-9
- The null MSC pilot in canine atopic dermatitis, routinely omitted from vendor literature — Hall MN, Rosenkrantz WS, Hong JH, Griffin CE, et al. Evaluation of the potential use of adipose-derived mesenchymal stromal cells in the treatment of canine atopic dermatitis: a pilot study. Vet Ther. 2010. PMID 20957613 https://pubmed.ncbi.nlm.nih.gov/20957613/
- Immune-privilege claims are not defensible - both equine and canine MSCs generated antibody titres in dogs — Punzon E, Garcia-Castillo M, Rico MA, Padilla L, Pradera A. Local, systemic and immunologic safety comparison between xenogeneic equine umbilical cord mesenchymal stem cells, allogeneic canine adipose mesenchymal stem cells and placebo: a randomized controlled trial. Front Vet Sci. 2023;10:1098029. PMID 37266387. DOI 10.3389/fvets.2023.1098029 https://pubmed.ncbi.nlm.nih.gov/37266387/
- The n=80 canine RCT behind DogStem - an osteoarthritis joint endpoint, EMA-authorised, not FDA-approved — Punzon E, Salguero R, Totusaus X, Mesa-Sanchez C, Badiella L, Garcia-Castillo M, Pradera A. Equine umbilical cord mesenchymal stem cells demonstrate safety and efficacy in the treatment of canine osteoarthritis: a randomized placebo-controlled trial. J Am Vet Med Assoc. 2022;260(15):1947-1955. PMID 36198051. DOI 10.2460/javma.22.06.0237 https://pubmed.ncbi.nlm.nih.gov/36198051/
- BPC-157 in dogs is pharmacokinetics only, not efficacy — He L et al. Front Pharmacol. 2022;13:1026182. PMID 36588717. DOI 10.3389/fphar.2022.1026182 https://pubmed.ncbi.nlm.nih.gov/36588717/
- Antimicrobial host-defence peptides are a different class with real in-species otitis data - do not conflate with regenerative peptides — Bannach TC, Mongruel ACB, Evangelista AG, et al. Comparative Efficacy of a Novel Topical Formulation with Antimicrobial Peptides and Encapsulated Plant Extracts Versus Conventional Therapies for Canine Otitis Externa. Pathogens. 2025;14(11):1112. PMID 41305350. DOI 10.3390/pathogens14111112 https://pubmed.ncbi.nlm.nih.gov/41305350/
- Atopic canine ears are deficient in their own host-defence peptides - mechanism, not a product claim — Santoro D. Comparison of the quantity and antimicrobial activity of host defence peptides in ear canals between healthy and atopic dogs: A preliminary study. Vet Dermatol. 2023;34(5):452-459. PMID 37088888. DOI 10.1111/vde.13164 https://pubmed.ncbi.nlm.nih.gov/37088888/
Tracking response
How you know whether it is working
Otitis Index Score (OTIS3): erythema, oedema/swelling, erosion/ulceration and exudate, each scored 0-3 per ear, plus separate pruritus and pain scores. A total score of 4 or more distinguished affected from healthy ears (91.1% sensitivity, 100% specificity) and a score of 3 or less was 100% sensitive and 91.9% specific for clinical success. Cytology should be repeated alongside the score before therapy is stopped, because clinical appearance alone over-estimates cure. Hearing and vestibular function should be checked at every recheck while a gentamicin-containing or fluoroquinolone-containing product is in use.
Nuttall T, Bensignor E. A pilot study to develop an objective clinical score for canine otitis externa. Vet Dermatol. 2014;25(6):530-7,e91-2. PMID 25130194. DOI 10.1111/vde.12163. Note the honest limit: the authors describe this as a pilot study and concluded the 0-3 OTIS3 is suitable for FURTHER validation by a larger group of clinicians. Later trials (PMID 30305092, PMID 32192496, PMID 39210729, PMID 41305350) have used it as their primary or key outcome measure, and Santoro 2023 (PMID 37088888) refers to it as a previously validated score, but it should be described as a reliability-tested index in wide trial use rather than as a formally validated instrument.
Suggested cadence: Baseline at diagnosis. First recheck at day 7-14 depending on the product used and the severity. Definitive recheck with otoscopy plus repeat cytology at day 28 before declaring resolution and stopping therapy. For dogs with a recurrent pattern, a scheduled ear check every 3 months during the first year of treating the underlying allergic disease, and an owner check-in score monthly. Re-examine immediately, not at the next scheduled visit, if hearing loss, head tilt or vestibular signs appear - and if they appear during treatment with a gentamicin-containing product, the label instruction is to discontinue immediately and flush the canal with a non-ototoxic solution. In any dog receiving an otic corticosteroid together with an oral or topical body glucocorticoid, and in any diabetic dog, plan how cumulative steroid exposure will be monitored before the first dose rather than after.
Questions you can answer at home
- On a line from 0 to 10, how much has your dog scratched, rubbed or shaken at the ears in the last 7 days? (0 = not at all, 10 = constantly)
- Is there still a smell from the ear? Yes, a lot / A little / No
- Is there still discharge or gunk coming out of the ear, and what colour is it?
- Does your dog flinch, cry or pull away when you touch that ear? Yes / Sometimes / No
- Is your dog shaking the head or holding it tilted to one side? Yes / No
- Does your dog seem to hear you as well as before treatment started? Better / Same / Worse
- Has your dog become wobbly, circled, or had flickering eyes at any point since the medicine started? Yes / No (if yes, this is a same-day call)
- Out of the last 7 days, on how many did you manage to give every dose of the ear medicine exactly as directed?
- Did your dog shake any dose straight back out, or did you miss any doses? If so, did you call the clinic before deciding what to do?
- Has anyone given your dog any human medicine, or any medicine prescribed for a different animal, since the last visit? Yes / No
- Is any other dog or cat in the house scratching at its ears?
- Is your dog also on steroid tablets, a steroid spray, or a steroid injection for skin or allergy problems right now? Yes / No / Not sure
Last reviewed: 2026-09-12 · Every claim on this page carries a citation you can check. If one does not hold up, tell us and we will correct it. science@azzamedical.com
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