Bilateral Otitis Externa Research Articles

Clinical conundrum

A 4-year-old Italian Spinone presented with a history of recurrent bilateral otitis externa, starting at 4 month of age. The diagnosis and treatment of atopic dermatitis complicated by Pseudomonas infection are described.

Amyloidosis of the External Auditory Canal

We present a case of bilateral otitis externa that did not respond to local treatment. Cutaneous biopsies revealed bilateral amyloid depositions secondary to multiple myeloma. Persistent, identical bilateral canal lesions may be the only manifestation of treatable systemic disease and should be biopsied, even though their bilaterality argues against malignancy.

Necrotizing otitis externa in a 5-month-old infant

This report presents the case of a healed 5-month-old infant with necrotising (malignant) bilateral otitis externa from acute mastoiditis on the right side and sepsis caused by Pseudomonas aeruginosa infection. Despite of immediately performed mastoidectomy, targeted antibiotics and intensive local treatment, two third of both external auditory canal's epithelium had shown subcutaneous concentric necrosis and ejection which have been removed with repeated necretomies. After the remission of inflammatory symptoms, successful bilateral auditory canal reconstructions were performed. The observed right peripheral facial paresis at the beginning of disease remained stationary. The patient healed with residual symptoms after 2 months of treatment. Neither immune deficiency, nor diabetes could have been proven.

Variability of laboratory identification and antibiotic susceptibility reporting ofPseudomonasspp. isolates from dogs with chronic otitis externa

The purpose of this study was to evaluate interlaboratory variation in isolation and antibiotic susceptibility pattern of Pseudomonas spp. as reported to veterinarians for cases of canine chronic bacterial otitis externa. Twenty-six dogs with unilateral or bilateral bacterial otitis externa from multiple referral practices were included in this prospective study. Triplicate samples collected simultaneously from the same location in the external ear canal were randomly submitted to three laboratories for culture and susceptibility testing. Pseudomonas spp. were isolated from 18 of 34 (53%) ears. All three laboratories agreed on the presence of Pseudomonas spp. in 15 (83.3%) ears sampled. However, two laboratories agreed on two (11.1%) occasions, and on one occasion (5.5%) Pseudomonas spp. were identified in only one laboratory. Minimum inhibitory concentration (MIC) susceptibilities to 11 antibiotics were compared between laboratories B and C. Using laboratory-defined susceptibility of sensitive (S), intermediate (I) and resistant (R), none of the 16 Pseudomonas spp. with MIC data reported had identical patterns of antibiotic susceptibility. Agreement in susceptibility to individual antibiotics was observed in 13 of 16 (81%) occasions for amikacin and gentamicin, 10 of 16 (63%) occasions for ticarcillin, and nine of 16 (56%) for enrofloxacin. These results indicate that Pseudomonas spp. were identified by all three laboratories chosen for this study in 83% of the time. Moreover, antibiotic susceptibility patterns and MIC values reported to veterinarians may not agree between laboratories. Veterinarians should interpret bacterial culture and susceptibility results with multiple caveats including variability between laboratories.

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.

P‐61 Bilateral ear canal neoplasia in three dogs

Bilateral ear canal infections are common in dogs. They are caused by different predisposing factors, such as allergies, keratinization disorders and conformation abnormalities. Ear canal neoplasia is usually associated with unilateral disease. 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 proliferation of both ear canals that did not respond to glucocorticoids. Treatment consisted of total ear canal ablation and tissues were submitted for histopathologic evaluation. Case 1 (10‐year‐old male cocker spaniel) was diagnosed with cerumenous gland carcinoma. Cases 2 and 3 were diagnosed with squamous cell carcinoma. Case 1 was diagnosed 3 years earlier as having a keratinization disorder responsible for the chronic ear disease. Case 2 (5‐year‐old female French bulldog) was diagnosed 4 years earlier with atopic dermatitis, which did not respond to hyposensitization and only partially responded to glucocorticoid therapy. Case 3 (9‐year‐old male German shepherd) was diagnosed 2 months earlier with unilateral ear canal proliferation; however, otoscopic examination showed bilateral proliferation that obstructed both canals. In summary, bilateral ear canal neoplasia should be considered in cases of nonreponsive, proliferative aural pathology. Funding: Self‐funded.

P‐16 Treatment of Malassezia otitis in dogs: a comparative field trial

Otitis externa (OE) is a very common disease of dogs. Various treatments are available for OE, but most commercial preparations contain a mixture of antifungal, anti‐inflammatory drugs and antibiotic agents. The aim of this study was to evaluate if a commercial product containing clotrimazole, marbofloxacin and dexamethasone (Aurizon®) was more effective than the use of a topical antifungal agent econazole (Daktarin®) used alone to treat Malassezia otitis. Dogs presenting with bilateral OE and numerous yeasts on cytological examination were included. Twenty dogs aged from 1 to 14 years old were treated in this trial (40 ears, 20 in each group). Each case was treated with Aurizon® (four drops) in one ear and Daktarin® in the other ear. Criteria analysed were pruritus (visual analogue scale), erythema, amount of cerumen, and the number of yeasts on cytologic smears. All animals demonstrated a good improvement in Malassezia counts after either treatment. Significant differences were noted in favour of Aurizon® for erythema, cerumen, and pruritus on various days of evaluation. This study demonstrated the superiority of a mixture of corticosteroids and antifungal agent in comparison with an antifungal agent used alone for the treatment of Malassezia OE. Funding: Self‐funded.

Transcription levels of Pseudomonas aeruginosa exotoxin a gene and severity of symptoms in patients with otitis externa.

Polymerase chain reaction (PCR)-based detection and transcription of the gene encoding a potent virulence factor, the exotoxin A, were done on 32 isolates of Pseudomonas aeruginosa belonging to 23 genotypes. These isolates were obtained from 22 patients who were admitted to the emergency room in a medical center during a 5-month period with the diagnosis of either unilateral or bilateral otitis externa. Patients showed symptoms that ranged from mild to severe. PCR amplification of a 396-bp fragment of the gene encoding the exotoxin A was done on extracted DNA. Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) was performed on extracted RNA to detect exotoxin A gene mRNA transcripts. Quantitation of RT-PCR amplicons from P. aeruginosa isolates associated with mild and severe symptoms was determined by end-point titration of c-DNA and scanning of amplicons with the Storm Gel and Blot Imaging System. Data have shown that all of the 32 isolates of P. aeruginosa carry the exotoxin A gene, and all isolates with the exception of two had the exotoxin A transcription demonstrated by the production of a 396-bp amplicon from RT-PCR-amplified RNA. The remaining two isolates amplified fragments that were slightly smaller than the expected size. Additional studies are needed to characterize these two mRNA transcripts. Transcription levels of exotoxin A gene associated with severe symptoms were significantly more elevated than those associated with mild to moderate symptoms. Studies are under way to determine expression of P. aeruginosa exotoxin A by detecting quantitatively levels of the translated exotoxin A protein produced by isolates associated with severe and mild to moderate symptoms.

Comparative analysis between Pseudomonas aeruginosa genotypes and severity of symptoms in patients with unilateral or bilateral otitis externa.

Random amplified polymorphic DNA (RAPD) analysis was done on 32 isolates of Pseudomonas aeruginosa. These isolates were obtained from 22 patients who presented to the emergency room in a major medical center in Beirut, Lebanon, during a 5-month period with the diagnosis of either unilateral or bilateral otitis externa. Patients had yellowish to greenish discharge, moderate to severe external auditory canal swelling, moderate to severe pain, and periauricular cellulitis. None of these patients had intrinsic predisposing factors. An ear swab was obtained from both ears of patients, cultured on trypticase soy agar. P. aeruginosa was identified on the basis of pyocyanine production and API identification kits. RAPD analysis was done by using two primers (10 mer and 21 mer primers) and appropriate PCR conditions on extracted DNA. Our data have shown 23 RAPD patterns (A-W) distributed among the 32 P. aeruginosa isolates. RAPD patterns were reproducible. Twenty of 32 isolates were recovered from 10 patients with bilateral otitis externa. The remaining 12 of 32 isolates were recovered from 12 different patients with unilateral otitis externa. Eleven RAPD patterns (A,B,C,D,E,F,H,I,R,U,V) were associated with severe clinical symptoms, including severe pain, severe external auditory canal swelling, periauricular cellulitis, and a yellowish discharge. The remaining RAPD patterns were not associated with severe infections. This denotes a possible association between certain genotypes and severity of symptoms.

Effect of total ablation of the external acoustic meatus and bulla osteotomy on auditory function in dogs

Summary: Seven dogs with end-stage bilateral otitis externa were evaluated for auditory function before and after bilateral total ear canal ablation and lateral bulla osteotomy. Evaluations were performed by owner questionnaire and by recording brainstem auditory-evoked responses. Prior to surgery, all dogs could hear a loud voice or noise, however, only 3 dogs responded to a voice spoken at a normal level. Of the 14 ears tested electrodiagnostically, only 1 did not have a response, using air-conducted or bone-conducted stimuli. After surgery, 2 dogs responded to a normal voice, but all 7 responded to loud voices or noise. Three ears that had recordable brainstem auditory-evoked responses to air-conducted stimulation prior to surgery, failed to respond after surgery. Ears that responded to bone-conducted stimulation prior to surgery also responded after surgery.

A randomized prospective comparision of two methods of administering topical treatment in otitis externa

Ten patients with bilateral moderate or severe otitis externa were studied. Following aural toilet each patient was subjected to two different treatments: one ear had alternate day dressings containing a topical antibiotic/steroid mixture, while the external canal of the other was filled with the same topical preparation (sump filling). Improvement in the severity of the otitis externa was assessed after 1 week. 9 out of 10 ear canals improved in each group. An estimate of the relative cost of each treatment was made and sump filling was found to be less expensive. The results suggest that sump filling is a low cost alternative to standard treatment in moderate and severe otitis externa.

Sensitization to Topical Antibiotics

To the Editor.— In his letter in the January 1978Archives(114:130) Dr Herwick described a case of prurigo in a woman from the San Francisco Bay area that he ascribed to the presence of the canine (and feline) ear mite Otodectes cynotis in the patient's recently acquired dog. Report of a Case.— In November 1977 a young dog was referred to me because the owner, a 50-year-old housewife, had been suffering from recurrent, pruritic eruptions on her torso and extremities ever since she acquired the dog some nine months earlier. The dog proved to have a bilateral otitis externa due to a heavy infestation with O cynotis . In brushings from the coat of the animal I found two mites that I first thought to be aberrant ear mites but that were subsequently identified as the canine scurf mite Cheyletiella yasguri . This mite may infest dogs asymptomatically but is quite

Anesthesia of internal ear following application of topical anesthetic to middle ear.

IN THE treatment of patients with a perforated drum membrane, it is customary to apply a moderately caustic solution, such as 10% silver nitrate, by means of a cotton-tipped applicator to the edge of the perforation. It happens occasionally that some patients experience severe pain following this treatment. To render this treatment tolerable to such patients, it has been my custom to apply to the perforation a pledget of cotton moistened with a topical anesthetic prior to the application of silver nitrate. Two of the patients so treated have experienced transitory anesthesia of the internal ear. One experienced deafness; the other, vertigo. The case reports follow: Case1.—J. B. M., a 20-year-old white youth, was under treatment for bilateral otitis externa in July and Aug., 1947. During the course of treatment, the canal and drum of the left 32 Audiogram showing results of application of topical anesthetic to middle ear.