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Iwona Taszkun ©
University of Life Science in Lublin (Poland) Department and Clinic of Internal Diseases
EVALUATION OF CLINICAL CASES OF CANINE OTITIS EXTERNA -OWN STUDIES IN YEAR 2004-2008
Abstract
During 2004-2008 in Dermatological Consulting Room of University of Life Sciences Veterinary Clinics in Lublin 668 dogs were seen with otitis externa, what was presenting 40.29% of all consulting room patients, therein 440 patients (65.87% of patients with otitis externa) were diagnosed skin hypersensitivity. Average patients' age with first time occurrence of otitis externa was 1.76 years, with another time occurrence - 6.49 years. Unilateral otitis externa were founded in 31.6% of patients, and bilateral in 68.4% of patients of investigated group. Most group was represented by dogs treated another time with bilateral otitis externa.
Key words: canine otitis externa, external ear diseases, atopy, food hypersensitivity
Introduction
Otitis externa in dogs is a disease state of outer ear and ear canal with complicated etiopathogenesis, in acute phase characterized by oedema, erythema, pain (mange) and increased excretion of skin glands of the external ear canal, while in chronic phase by impetiginization marked with hyperkeratosis, hyperpigmentation, and skin hyperplasia. Many factors influences development of otitis externa (Griffin, Kwochka, MacDonald 1993, Rosenkrantz 1999, Gotthelf 2000, Scott, Miller, Griffin 2001), therefore for clinical assessment primary, secondary and recurrent otitis externa is distinguished. Primary factors causing otitis externa are parasites (itch mites, demodex, ticks, fleas), foreign bodies irritating ear canal, allergy (atopic dermatitis, food allergy, drugs hypersensitivity) and autoimmunological diseases (lupus, pemfigoid), which entails disorders of keratinisation, skin glands excretion and immunological mechanisms in ear. Not meaningless are additional factor like shape ear auricle, anatomical stricture of ear canal, extensive coat and presence of efflorescences (tumors, polyps). Secondary inflammations of ear canal, acccording to opinion of many authors (Masuda 1984, Griffin, Kwoczka, MacDonald 1993, Carlotti, Tailleu-LeRoy 1997, Rosenkrantz 1999, Gotthelf 2000, Scott, Miller, Griffin 2001) occurs in ear changed by primary or predisponent factors. Bacteria and fungi or drugs, which in best of times disrupting immunological mechanisms in ear, raise inflammations and convey to pathological changes.
Combination of primary, secondary and predisponent factors results in recurrent or insusceptible for treatment otitis externa, what is largest diagnostical and therapeutical problem for veterinary practitioner.
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Study purpose
In presented publication otitis externa in dogs being patients in dermatological consulting room of Department and Clinic of Internal Medicine, Faculty of Veterinary Medicine in University of Life Sciences in Lublin.
Materials and methods
In years 2004-2008 in Dermatological Consulting Room of University of Life Sciences in Lublin 1658 dogs were applied with skin lesions, whereof in 668 cases (40,29%) the reason of consult was inflammation states of ear canal. Questions stated to dogs owners in the anamnesis was concerning uni- or bilaterality of otitis externa and occurrence of other skin symptoms. Frequency, therapy methods and its efficacy was determined in cases of recurrent otitis externa. Clinical examination was conduced in every patient to ascertain coexistence of other dermatological symptoms, ear auricle and external ear canal was explored with otoscope. Cerumen was microscopically investigated with use of chlorolactophenol in every dog with otitis externa. Cytological examination of material taken from the horizontal part of ear canal was conduced after staining with the Hemacolor (Merck).
Results and discussion
In years 2004-2008 in Dermatological Consulting Room of University of Life Sciences in Lublin 1658 dogs were received with skin lesions, whereof most was crossbreed (26,84%) and dogs in following breeds: German Shepherd (15,56%), Dachshund (13,99%), Boxer (13,45%), Terrier (6,33%) and Spaniel (6,28%). Number of dogs with help requested because of otitis externa, as well as with primary cause diagnosed as skin hypersensitivity disease (AD- atopic dermatitis and/or FA/H - food allergy/hypersensitivity) is also inserted. that in years 2004-2008 668 dogs with otitis externa were received, which constituted 40,29% of all Consulting Room patients, therein 440 (65,87% of patients with ear inflammation) was diagnosed skin hypersensitivity disease (AD, FA/H).
Most patients with otitis externa was belonging to following breeds: Boxer, Terrier, Spaniel, Shar-pei, Schnauzer, Dogue de Bordeaux, Dalmatian, Setter, Labrador, French and English Bulldog. At the same time otitis externa is the rarest (under 20%) cause of dermatological consult in crossbreeds and Pekineses. In part of dogs with otitis externa allergic skin disease (AD, FA/H) was diagnosed. Most of them were Labradors, French and English Bulldogs, Terriers (including American Staffordshire Terrier), Dogues de Bordeaux, Rottweilers, Dalmatians, Setters, German Shepherds (>70% of dogs with otitis externa). Hypersensitivity disease was diagnosed rarest as a reason of otitis externa in Poodles, Dachshunds, Schnauzers and Pekineses (<50% of dogs with otitis externa).
Age of examinated dogs was fluctuating in wide range, average 4.8 years. The youngest patient was in age of 5 weeks, the oldest - 16 years. Dogs under age of 1 year constituted 20.4% of patients with otitis externa, in age of1-3 years - 40.3%, adult in age of 3-7 years - 25.6%, and older ones, over 7 years - 13.7%. Average age of patients with first occurrence of otitis externa was 1.76 years, and average age of patients with another occurrence - 5.49 years.
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In general, unilateral otitis externa occurred in 31.6% of patients, and bilateral - in 68.4% of examinated group.
Clinical attributes of acute inflammation state characterized by painfulness of ear base, external ear canal skin erythrema and oedema, local heat raise and presence of increased amound of cerumen was ascertained in 32.5% of investigated dog population. Clinical signs of chronic inflammation state characterized by external ear canal and internal side of ears auricle skin impetiginization with coexistent inflammation state, what evidences about recurrent character of disease, was ascertained in 67.5% of patients. The largest group (49.4%) was dogs treated another time with bilateral otitis externa.
Amongst dogs being Dermatological Consulting Room patients, dominating group (68.4%) were dogs with bilateral ear inflammation, although there was some specimens with unilateral (31.6%) ear inflammation.
Unilateral recurrent ear inflammation was ascertained in more than 18% of dogs. Amongst this group most frequent were patients witch coexisting skin symptoms with otitis externa.
In group of dogs with bilateral otitis external, most frequent (49.4%) were cases with recurrent otitis externa, often with occurrence of others dermatological syndromes.
Assessing etiological factors isolated from cerumen in examinated population of dogs most frequently (53.3%) discovered inflammation state was mixed (bacteriofungal), less frequently only bacterial (24.1%) or fungal (19%) and rarest parasitic (3,6%) caused by Otodectes cynotis. Most frequent patient's group were dogs with bilateral bacteriofungal otitis externa affected another time - 28.7% of all patients with otitis externa and 54% with otitis externa cause by bacteriofungal infection. Often, in group with bilateral otitis externa bacterial infection was present -16.5% all patients with otitis externa.
In group of young dogs, i.e. in age less than 1 year most cases (7.6%) were caused by fungal infection, less bacterial (4%) and mixed (6%). However it was the age group with most frequently founded parasitic otitis externa (Otodectes cynotis) -admittedly 2.4% of all dogs with otitis externa, but 75% all cases with Otodectes cynotis as identified etiological factor.
In age group of dogs in age of 1-3 years (Tab. 5) most common infections in otitis externa were mixed (bacteriofungal) in 24% of consulted dogs. Similiter situation was in rest of age groups. In dogs in age over 3 years parasitic infections weren't doscowered.
According to Griffin, Kwochka, MacDonald (1993) and Lynette (2004) ear inflammations in dogs are 10-20% of cases requiring veterinary consult, and 50% chronic states of otitis externa in dogs leads to tympanic membrane lesion or middle ear inflammation. In about 5-10% of cases primary reason are parasites- Otodectes cynotis (Griffin 1993, Rosser 2004), and in 20-90% - immunological diseases (Rosser 2004), mainly food hypersensitivity and atopic dematitis. In dogs with hypersensitivity (Griffin, Kwochka, MacDonald, 1993) reccurent, bilateral otitis externa can be the only clinical symptom of disease, what is notified in 20% of cases,
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and coexists with other clinical symptoms in 80%. However in atopic dogs it is the only clinical symptom in 3-5% cases, and coexisting symptom in 55% of cases.
Summary
1. Bilateral otitis externa in dogs is more frequent than unilateral. In about 70% it has recurrent character
2. In 65% of cases disease with skin hypersensitivity (atopic dermatitis and/or food allergy.hypersensitivity) was recognized as a cause.
3. Clinical picture of otitis external is divergent and dependent of coexistence of etiological and predisponent factors. Most numerous group are patients with mixed (bacteriofungal) otitis externa (53.3%), and less numerous - parasitic (3.6%)
4. Otodectes cynotis as otitis externa causing factor is mostly identified in young dogs, i.e. in age under 1 year.
References:
1. Carlotti D., N., Tailleu-LeRoy S.: L'otite externe chez le chien: Etiologie et clinice, revue bibliographigueet etude retrospective portent sur 752 cas. Prat. Med. Chir. Anim. Comp., 1997, 32, 234-239,
2. Gotthelf L.: Small animal ear diseases. An illustrated guide. W.B. Saunders Comp.2000
3. Griffin C.,E., Kwochka K., W., MacDonald J., M.: Current Veterinary Dermatology. The Science and Art of Therapy. Chapter 24,. Mosby, St. Louis, 1993, 245-264
4. Lynette K. Cole: Otoscopic evaluation of the ear canal. Vet. Clin. Small Anim. 2004, 34, 397-410
5. Masuda H.: The aerobic bacterial flora of the middle and external ears in the normal dogs. J. of Small Anim. Prac. 1984, 25, 269-276,
6. Rosser E., J.: Causes of otitis externa. Vet. Clin. Small Anim. 2004, 34, 459468
7. Scott D.W., Miller W.H., Griffin C.E.: Muller & Kirk's Small Animal Dermatology. 6th edition. Saunders Comp. Philadelphia 2001,1203-1232
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