The association between the signalment, common causes of canine otitis externa and pathogens

Objective : To determine whether associations exist between pathogens, allergies, conformational abnormalities, endocrinopathies and signalment in canine otitis externa (OE). Methods : Medical records of 149 dogs which met predetermined inclusion criteria were evaluated retrospectively. Correlations between pathogens and the presence of allergy, endocrinopathy, conformational abnormalities and signalment were evaluated statistically. Results : The shar‐pei, German shepherd and cocker spaniel breeds were over‐represented compared with the hospital's breed distribution (P<0·001). German shepherd dogs and cocker spaniels were statistically more prone to infection with rod‐shaped organisms and Labrador retrievers less than other breeds (P=0·034). Almost all dogs that were older than five years when diagnosed with OE had cocci (P=0·01) and also had higher levels of rods (P=0·028). The incidence of rods was higher in endocrinopathies (P=0·004), while that of Malassezia spp. tended to be higher in allergies (P=0·098). There were no statistically significant differences among the groups for all the other parameters examined. Clinical Significance : OE infection is usually not influenced by primary causes or predisposing factors. Endocrinopathies may be followed by a more severe otitis, however. OE may be more severe when it affects older dogs.     

A review of techniques for the investigation of otitis externa and otitis media

Otitis externa, inflammation of the externa ear canal, is relatively easy to diagnose based on the history and physical examination findings. The diagnosis of otitis media, inflammation of the middle ear cavity, is more challenging, with the work-up being both costly and, at times, invasive. The pathogenesis of otitis externa has been classified into predisposing, primary, and perpetuating factors. It is critical to the management of ear disease that the clinician recognize and investigate which factors are contributing to each individual patient's ear disease. Failure to identify and address the primary and/or predisposing factors is the most common cause of chronic recurrent otitis externa. Chronic inflammation of the ear canal leads to the development of the perpetuating factors, which may be the major reason for treatment failure, regardless of the primary cause of the ear disease. In this article, the predisposing, primary, and perpetuating factors involved in ear disease will be presented, along with a review of the techniques used in the diagnosis of otitis externa and otitis media.     

ULTRASONOGRAPHIC FEATURES OF GRASS AWN MIGRATION IN THE DOG

The aim of this study was to describe the ultrasonographic features of grass awns in soft tissue. A 10 MHz linear transducer was used. Ultrasound images from 25 dogs (27 awns) were collected and compared with the results from water bath studies using wild oat seeds (Avena spp.) collected in the field. Wild oat seeds were the most common grass awn found in soft tissue of dogs. Ultrasonographically grass awns appeared as a double/triple spindle-shaped echogenic interface within soft tissue. The same appearance was observed in water bath studies. In four dogs, the grass awn was removed surgically with a clamp introduced into a fistulous tract, using sonographic guidance. The grass awn was not found surgically in only three dogs, suggesting more attention during surgery. Ultrasonography is a useful diagnostic imaging technique to identify grass awns within soft tissue.     

Total Ear Canal Ablation Clinical Results in the Dog and Cat

The clinical results of 39 consecutive ear ablations (in 28 dogs and three cats) performed over a 15-year period were reviewed. Indications for ear canal ablation included hyperplastic tissue stenosis of the horizontal ear canal (23), failed lateral ear resections (13), and horizontal ear canal neoplasms (3). Ear ablation was successful in alleviating persistent signs of otitis in eight of 15 dogs with horizontal ear canal stenosis due to hyperplastic tissue, seven of 10 dogs with unsuccessful lateral ear resections, and two of five animals (three cats and two dogs) with horizontal ear canal neoplasms (follow-up time periods greater than 5 months). Surgical complications occurred following 82% of the ablations; wound infections (41%) and facial nerve damage (36%) were most common. Local wound and antibiotic therapy successfully treated prolonged drainage following ablation in five of nine dogs. Bulla osteotomy and drainage were successful in the treatment of three dogs (four ears) that were unresponsive to medical therapy with postoperative ear fistula following ablation, one of two dogs with prolonged ear drainage following ablation for failed lateral ear resection, and one dog with recurrence of signs of inner ear disease following ablation (follow-up period, 1 month to 4 years; mean, 3.4 years). Facial nerve damage caused by ablation was transient in nine of 14 ears, with most deficits returning to normal within 2 weeks.     

Potential factors affecting the outcome of dogs with a resection of the lateral wall of the vertical ear canal.

The records of 60 dogs that had a resection of the lateral wall of the vertical ear canal (Zepp) were examined. The surgical outcomes were evaluated in association with the following variables: breed, sex, age of onset of the otitis externa, duration of the disease before the surgery was performed, treatment received for the otitis externa, the status of the ear and tympanic membrane at the time of the surgery, the culture results, and concurrent medical problems. The outcome of surgery was acceptable in 45% and unacceptable in 55% of the cases. Breed was the only factor that could be correlated with the outcome. The procedure failed in 86.5% of the cocker spaniels. When surgical outcomes in breeds other than cocker spaniels were evaluated, 63% were acceptable and 37% were unacceptable. Sharpeis were found to have an ear canal of small diameter compared with that of other breeds and a tendency to have better outcomes.     

Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs

The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.     

Bilateral ear canal neoplasia in three dogs

Bilateral ear canal infections are common in dogs. Ear canal neoplasia is usually associated with unilateral problems, and is uncommon in dogs. To the best of the author's knowledge, bilateral aural neoplasia has not been reported in dogs, and only four case reports were found in the human literature. This report presents three dogs that had bilateral tumours in their ear canals. They were presented with bilateral otitis externa. All three dogs exhibited tissue proliferation of both ear canals that did not respond to glucocorticoids. Treatment consisted of total ear canal ablation, and tissues were submitted for histopathological evaluation. Case # 1 (a 10-year-old, male cocker spaniel) was diagnosed as ceruminious gland carcinoma. Cases # 2 and 3 were diagnosed as squamous cell carcinoma. Case # 1 was diagnosed 4 years earlier as having keratinization disorder, which was causing its chronic ear problems. Case # 2 (a 5-year-old, female French bulldog) was diagnosed 4 years earlier as having atopic dermatitis, which did not respond to hyposensitization, and only partially responded to glucocorticoids therapy. Case # 3 (a 9-year-old, male German shepherd) was diagnosed by the referring veterinarian as having unilateral ear canal proliferation 2 months prior to presentation. However, otoscopic examination showed bilateral proliferation that obstructed both canals. In summary, bilateral ear canal neoplasia should be considered in cases of nonresponsive, proliferative aural pathology.     

ULTRASONOGRAPHIC FEATURES OF GRASS AWNS IN THE URINARY BLADDER

Grass awns are a common cause of foreign body disease in animals, but little is known about their presence in the lower urinary tract. The ultrasonographic features of grass awns in vivo and in vitro have been described in detail. The purpose of this report is to describe the clinical and sonographic features of grass awns in the urinary bladder of dogs and cats. Three male Yorkshire terriers (one of which was examined twice) and one female domestic short‐haired cat were evaluated for signs of lower urinary tract disease, and an intravesicular grass awn was suspected based on ultrasound examination. The grass awn appeared ultrasonographically as a bladder stone (n=1) or a linear hyperechoic structure (n=4) with or without acoustic shadowing that was easy to identify due to contrast with surrounding urine. The presence of a grass awn within the urinary bladder was confirmed during exploratory surgery. In all patients, the route of entry of the grass awn was thought to have been retrograde migration from the urethral opening. The ultrasonographic appearance of grass awns in the bladder is consistent with that in other tissues.     

New combination for the therapy of canine otitis externa I Microbiology of otitis externa

In order to compound a new drug comblnatlon agalnst canlne otitis externa (OE), 515 dogs affected wlth OE were subjected to physical examlnatlon and mlcroblologlcal analysis of their ear exudates. OE was erythematous-cerumlnous In 83 per cent and suppurative In 17 per cent of the patlent material. Erythematous-cerumlnous lnflammatlons were characterlsed by severe prurltus and accumulatlon of brownlsh, greasy cerumen In the audltory canal. The yeast Malassezla jmchydermat/s was Isolated from the ears of 76 per cent of the dogs, often In comblnatlon wlth Staphylococcus lntermedlus bacterla. M pachydermatls showed the most sensltlvlty, In decreasing order of efflcacy, to ketoconazole, econazole, clotrlmazole, mlconazole and nystatln. S lntermedlus Isolates were most sensltlve to amoxyclllln-clavulanlc acld, enrofloxacln, cephalexln and gentamlcln. The mlcroorganlsm most frequently Isolatcbd from dogs wlth suppurative OE was Pseudomonas aewglnosa; In some cases Proteus, Streptococcus and Pasteurella were also Isolated. The P aeruglnosa Isolates showed the highest sensltlvlty to gentamlcln, polymyxln B and tobramycln.     

Studies of certain factors affecting the microenvironment and microflora of the external ear of the dog in health and disease

A total of 187 dogs, 110 with clinical signs of otitis externa (OE), and 77 without history or clinical signs of OE, were examined microenvironment and microbiological analysis of their ear exudates made. The aural temperature and humidity of 160 dogs were measured. There were no significant difference between healthy dogs and OE dogs. German shepherd showed relatively lower temperature (p<0.01) and higher humidity (p<0.01). The mean log(10) number of microbial organisms of ears of OE dogs (4.16 +/- 0.31 cfu/g) was significantly increased, compared to that from the ears of non-OE group (2.55 +/- 0.24 cfu/g). Pseudomonas spp. and Proteus spp. were detected only from OE dogs. In addition, three enterotoxigenic Staphylococcus aureus were isolated from ear specimens.     

Studies on the role of routes of allergen exposure in high IgE-producing beagle dogs sensitized to house dust mites

The current study aimed to investigate the role played by oral, epicutaneous, and inhalation routes of exposure to house dust mites (HDM). The colony of high IgE-producing beagle dogs has been shown to develop pruritic dermatitis compatible with atopic dermatitis following environmental exposure (EE) to HDM. In crossover experiments, the response to EE was compared to two modified challenges, oral exposure (OE) and snood and muzzle exposure (SME). For OE, HDM were fed daily for 3 days. For SME, ingestion of allergen was prevented but there was inhalation and epicutaneous exposure to all body regions except to one ear. In all experiments, dogs were challenged for three consecutive days, and evaluated before, 6 h after exposure and daily thereafter, for 5 days. After a wash-out period, groups were crossed-over so that each dog was randomly challenged to all three protocols. Clinical scores were analysed using least squares analysis of variance. All dogs developed pruritic dermatitis regardless of the protocol. With OE, lesions developed in the same body regions as with EE although scores were lower. This difference became more evident after the first 3 days when OE scores decreased and EE scores continued to increase. The scores of covered and uncovered ears did not differ with SME. Scores for the remainder of the body were significantly lower than for EE. The development of lesions on covered ears supports the importance of inhalation or a systemic reaction to epicutaneous exposure in other areas. It is concluded that all routes are important and have additive effects, that route of exposure does not determine the distribution of lesions and that continuous epicutaneous exposure probably plays the most important role.     

Canine atopic dermatitis in Greece: clinical observations and the prevalence of positive intradermal test reactions in 91 spontaneous cases.

Atopic dermatitis was diagnosed in a total of 91 dogs by combining the compatible historical evidence and clinical signs with the presence of one or more positive intradermal test reactions well correlated with the exposure to the aeroallergens and the seasonality of the clinical signs. Compared to the general hospital population Yorkshire terriers, Chinese Shar-Peis and cocker spaniels showed a strong predilection. No such predilection was found regarding the sex of the animals. The age of the dogs at the onset of the clinical signs ranged from 2 months to 8 years (median: 2.5 years). Moderate to severe pruritus, noticed in all the 91 dogs, was either localized (29/91) or generalized (64/91) and non-seasonal (43/91), seasonal (19/91) or of unknown seasonality (29/91). The most common cutaneous lesions included erythema, hyperpigmentation, hypotrichosis and crusts; their body distribution was generalized (64%) or localized (36%) with the feet as the most common site of involvement. Five dogs that had unlesional skin were significantly younger and had been pruritic for a shorter period of time compared to the majority of our study population. Otitis externa (43/91) and bacterial pyoderma (30/91) were the most common conditions associated with atopic dermatitis, while the prevalence of Malassezia dermatitis was very low (2/91). Of the other allergic skin diseases flea allergic dermatitis was the most common (29/91) followed by food hypersensitivity (2 out of the 15 dogs tested). The majority of the dogs demonstrated multiple sensitivities to the 50 aeroallergens tested, while domestic mites (77/91), and particularly Dermatophagoides farinae (64/91), were the most commonly implicated. The total number of the positive intradermal test reactions was increasing parallel to the age of the dogs but it was negatively associated with the presence of skin lesions on the carpal and tarsal joints.     

Isolation of Malassezia pachydermatis and M. sympodialis from the external ear canal of cats with and without otitis externa

The objective of this study was to determine the presence of Malassezia spp. in the external ear canal of cats with and without otitis. Forty-five animals were studied, 20 with and 25 without otitis externa (OE). Cerumen or secretion from external ear canal samples was cultured on modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The isolates were analysed for macro- and micromorphology and identified by catalase tests and on the basis of growth on Tween 20, 40, 60 and 80. Malassezia spp. were isolated from 15 out of 20 (75%) animals with otitis and from 7 out of 25 (28%) cats without OE; the difference between the two groups was statistically significant (P < or = 0.05). Malassezia pachydermatis and M. sympodialis were isolated from 60% (12/20) and 40% (8/20) of cats with otitis, respectively, with no significant difference in the frequency of isolation between the two species. In the microflora of the healthy ear canal M. pachydermatis was significantly more common (6/25, 24%) than M sympodialis (1/25, 4%). The present investigation confirms that M. sympodialis can also act as an aetiological agent of feline OE, and if commercial veterinary laboratories do not use media with added lipids for the isolation of Malassezia spp., this might lead to false-negative results.     

Treatment of Traumatic Separation of the Auricular and Annular Cartilages Without Ablation: Results in Five Dogs

Five dogs were diagnosed as having unilateral separation of the otic cartilages (auricular and annular). Four dogs had sustained prior trauma (hit by a car). Clinical signs were typical of ear canal stenosis and included swelling at the base of the ear (n = 2), periotic fistulation (n = 2), head tilt toward the affected side (n = 2), and pain when opening the mouth (n = 1). Palpation revealed separation of the horizontal and vertical ear canals. Otoscopic findings included a shallow ear canal and a pseudotympanic membrane across the proximal end of the auricular cartilage. Findings at surgery confirmed the diagnosis of cartilage separation and included an exudate-filled horizontal ear canal and a blind-ending vertical ear canal. Surgical treatment involved isolating the distal end of the annular cartilage (horizontal ear canal), opening and evacuating the horizontal ear canal, and suturing the open end of the annular cartilage to the skin. The length of annular cartilage was variable among the dogs, although each dog had sufficient horizontal canal to appose skin to otic epithelium. The vertical ear canal was not surgically dissected or manipulated. The mean follow-up period was 46 ± 14 months (range, 31 to 68 months). All five dogs had patent horizontal ear canals when examined at the follow-up examination.     

Dermatologic disorders in dogs with diabetes mellitus: 45 cases (1986-2000)

OBJECTIVE: To characterize skin lesions and causative infections in diabetic dogs and evaluate other potential causes of dermatologic disorders, including concurrent endocrinopathies, allergic skin disease, and long-term corticosteroid administration. DESIGN: Retrospective study. ANIMALS: 45 dogs with diabetes mellitus (DM) that were examined by dermatologists. PROCEDURE: Medical records were reviewed for signalment; allergic conditions prior to development of DM; prior corticosteroid administration; and results of dermatologic examinations, ear and skin cytologic examinations, skin scrapings for parasites, bacteriologic and fungal culturing of ear and skin specimens, histologic examinations, and endocrine testing. RESULTS: Bacterial skin infection was the most common dermatologic disorder (n = 38 [84%]), followed by otitis (26 [58%]) and Malassezia-induced dermatitis (19 [42%]). Twenty-two (49%) dogs had pruritic skin disease consistent with allergic dermatitis, which preceded diagnosis of DM. Prior corticosteroid administration was reported in 21 (47%) dogs. Concurrent hyperadrenocorticism was diagnosed in 13 (29%) dogs, and concurrent hypothyroidism was diagnosed in 5 (11%) dogs. Iatrogenic hyperadrenocorticism was diagnosed in 1 additional dog. Only 10 (22%) dogs did not have a documented concurrent endocrinopathy or allergic disease that could have caused the dermatitis. CONCLUSIONS AND CLINICAL RELEVANCE: Bacterial and yeast-induced dermatitis and otitis develop in dogs with DM. Many diabetic dogs with dermatologic problems have a preexisting allergic condition, history of prior corticosteroid administration, or concurrent endocrinopathy that may be a more likely cause of dermatologic problems than DM alone.     

Diagnosis and medical treatment of otitis externa in the dog and cat

Otitis externa is no longer viewed as an isolated disease of the ear canal, but is a syndrome that is often a reflection of underlying dermatological disease. Causes are classified as predisposing (increase the risk of otitis); primary (directly induce otitis), secondary (contribute to otitis only in an abnormal ear or in conjunction with predisposing factors) and perpetuating (result from inflammation and pathology in ear, prevent resolution of otitis). Common primary causes include foreign bodies, hypersensitivity (particularly atopy and food allergy), keratinisation disorders (most commonly primary idiopathic seborrhoea and hypothyroidism) and earmites, particularly in cats. A systematic diagnostic procedure is required to identify causes and contributing factors. This should include history, clinical examination, otoscopy and cytology in all cases and culture and sensitivity as well as otitis media assessment and biopsy in severe and recurrent cases. Ancillary tests may be required depending on the underlying cause. Treatment consists of identifying and addressing predisposing and primary factors; cleaning the ear canal; topical therapy; systemic therapy where necessary; client education; follow-up; and preventive and maintenance therapy as required.     

The cytology of the external ear canal in the normal dog and cat

This study was conducted on 50 normal dogs and 52 normal cats in order to characterize the normal cytological findings in specimens taken from the vertical ear canal by swabbing. Yeast were detected in 96% of the dogs and 83% of the cats. Gram-positive cocci were found in 42% of the dogs and 71% of the cats. Rods were not seen. In dogs, the median numbers per high-power microscopic field (400x magnification) for yeast, cocci and keratinocytes were 0.2, 0 and 3.9, respectively. In cats, the median numbers were 0.2, 0.3 and 8, respectively. Nucleated keratinocytes were occasionally observed in both species, and should not be mistaken for a pathological process (parakeratotic hyperkeratosis).     

Surgical management of 43 cases of chronic otitis externa in the dog

: Over a seven-year period, chronic otitis externa was surgically managed in 43 dogs at the University Veterinary Hospital of University College Dublin. Lateral ear canal resection (LECR) was undertaken in nine of the 43 dogs: results were unsatisfactory, with a failure of the surgery in five of eight dogs and one dog lost to follow-up. Once end-stage otitis externa, with or without otitis media, is diagnosed, total ear canal ablation and lateral bulla osteotomy (TECA/LBO) is the best treatment option. In this series, 37 of 43 dogs underwent TECA/LBO and of the 29 dogs for which follow-up results were obtained 27 (93%) had an excellent or improved outcome to surgery. Complications following all procedures were most common in cases with a concurrent dermatopathy; therefore, definitive diagnosis and medical treatment for skin and ear disease is essential.     

New combination for the therapy of canine otitis externa II Efficacy in vitro and in vivo

A new, effective drug combination was developed for the therapy of canlne otitis externa (OE) by taking into consideration the microorganisms most frequently isolated from dogs affected with OE, their combination, their drug sensitivity and the type and incidence of ear canal inflammation. The antlmycotic active ingredient of the combination Is ketoconazoie, Its antlbacteriai component Is gentamlcin suiphate, while its antiphiogistic constltuent is mazipredone hydrochloride. Based upon the results of in vltro pharmacodynamic tests, the antifungal activity of the combination is superior to that of ketoconazoie used alone at the same concentration. A total of 210 dogs affected wlth OE were treated with the combination: 94-2 per cent of them became clinically symptomless and microbioiogicaiiy negative in an average of 8-5 days. No adverse reactions were observed In connection wlth the use of the drug combination. The therapeutic results can be attributed to the hlgh antifungal efficacy of the combhation demonstrated In vltro and to the favourable properties of the solvent mixture.     

Separation of the Auricular and Annular Ear Cartilages: Surgical Repair Technique and Clinical Use in Dogs and Cats

Objective— To report a surgical technique for primary repair of separation of the annular and auricular cartilages of the ear and long-term outcome.
Study Design— Case series.
Animals— Cats (3) and dogs (2) with ear canal separation.
Methods— Medical records (1998–2007) of dogs and cats with ear canal separation were reviewed. Long-term outcome was obtained by telephone interview of owners or referring veterinarians.
Results— Three cats and 1 dog had ear canal separation after being hit by a car; there was no history of trauma in 1 dog. Successful repair was achieved by a caudal approach to the ear canal, identifying and debriding separated cartilage edges and using primary repair. A patent ear canal was confirmed in all animals by otoscopy 4–12 weeks later and by ear canalography in 3 animals. Long-term outcome was excellent with no reported complications 10–90 months later (median 24 months).
Conclusions— Both acute and chronic separation between the annular and auricular cartilages, in the absence of middle ear disease, can be successfully treated using primary repair via a caudal approach to the ear canal, with excellent long-term outcome.
Clinical Relevance— Primary repair should be considered in animals with separation of the annular and auricular cartilages.