Prednisone for dog ear infection.The Challenge of Chronic Otitis in Dogs: From Diagnosis to Treatment
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Prednisone for dog ear infection.How to treat ear infection in dogs
She serves as scientific advisor and editor for several journals and has presented at many national and international conferences. Her professional interests include allergies, otic diseases, autoimmune disorders, multidrug-resistant infections, and equine dermatology. Canine chronic and recurrent otitis externa can be extremely challenging to treat and require multifactorial, step-by-step strategic plans.
Understanding otitis and its associated causes and contributing factors is an important initial step toward successful diagnosis and treatment. Understanding the multifactorial nature of otitis and paying attention to the different causes and contributing factors, not just the infection, is critical because the infection is usually only part of the problem Figure 1.
The most recently proposed classification for otitis includes primary and secondary causes and predisposing and perpetuating factors Table 1. Pathologic cycle for chronic otitis externa. Primary disorders initiate the inflammatory process within the ear canal and alter the aural environment, allowing secondary complicating factors, such as infections, to develop. The primary cause may be very subtle and often is unrecognized by the owner or even the veterinarian until a secondary complicating factor arises.
Most cases have a primary cause. No primary factor could be identified in 32 of cases. Allergic and hormonal diseases can be associated with unilateral or bilateral otitis, but bilateral otitis is more common.
Foreign bodies, neoplasia, and polyps are usually associated with unilateral otitis; however, bilateral problems have been reported.
Otitis externa secondary to allergies. Secondary causes occur in combination with primary causes or predisposing factors. The most common secondary causes are infections. When they are chronic and difficult to treat, it is usually because primary causes or perpetuating factors have not been adequately addressed. Predisposing factors alone do not cause otitis externa, but they facilitate inflammation by permitting the external ear canal microenvironment to be altered, thereby allowing pathogenic or opportunistic bacteria or yeast to become established.
It is important to eliminate as many of these factors as possible while realizing that some, such as ear conformation, cannot be changed. Perpetuating factors sustain and aggravate the inflammatory process and prevent resolution of, or worsen existing, otitis externa. In many cases, perpetuating factors prevent the resolution of otitis externa when treatments are directed only at primary and secondary causes.
These factors may be subtle at first but can develop into the most severe component of chronic ear disease. They are not disease specific and are most commonly seen in chronic cases. Perpetuating factors are the most common reasons for surgical intervention. A detailed and complete history is essential to help investigate the underlying cause and associated factors.
The ear examination allows the clinician to evaluate the amount and type of exudate in the ear canals; estimate the amount of otic inflammation; identify hyperplasia along with palpation of the horizontal and vertical ear canals , masses, and foreign bodies; and determine the status of the tympanic membrane eg, changes in structure or rupture. These findings help in determining whether medical management or surgery total ear canal ablation with or without bulla osteotomy is the best treatment.
Regular ie, handheld otoscopes should have a strong light and power source. If available, fiberoptic video-enhanced otoscopy eg, video-otoscope [ Figure 3 ] is extremely helpful in improving diagnosis and therapy because it not only allows visualization of fine details that may not be seen with regular otoscopes but also facilitates proper flushing of the ears, determination of disease extent, and discovery of indications for additional diagnostics and treatment eg, myringotomy, otitis media.
However, because of the expense to purchase and maintain this equipment, referral to a dermatologist may be necessary. Performing a complete physical examination, including a detailed dermatologic examination, can help in identifying an underlying or primary cause. Otic cytology establishes whether an infection is present in the ears and assists with the selection of topical therapy. Cytologic samples should be collected gently from the horizontal canal.
Exudate samples can be smeared onto a slide with mineral oil to look for mites. The most common type of coccoid bacteria found in the ears of dogs with otitis externa is Staphylococcus pseudintermedius , and the most common type of rod bacteria is Pseudomonas aeruginosa. This might explain why, in some cases, sensitivity results in vitro and response to topical therapy in vivo do not always correlate.
Clinicians should sample the middle ear separately if otitis media is confirmed when the tympanic membrane is intact. The types and sensitivity pattern of bacteria isolated from the middle ear may differ from those of bacteria isolated from the external canal.
Dogs with chronic, recurrent, and severe otitis and those with neurologic signs eg, vestibular signs or facial nerve paralysis , para-aural swelling, or pain on opening the mouth usually require diagnostic imaging to help identify contributing problems, such as middle ear disease eg, otitis media, neoplasia and otitis interna, that cannot be identified with regular otoscopy Table 2.
Patients with an apparently normal tympanic membrane may also have otitis media. This procedure is very helpful not only as a diagnostic tool but also as part of the treatment plan. This procedure should be performed under general anesthesia so that the ear can be completely cleaned and the ear canal and tympanic membrane examined. Anesthesia also allows the placement of an endotracheal tube, which precludes the aspiration of fluids that may pass through the middle ear into the auditory tube and then into the posterior pharynx.
Ideally, computed tomography of the tympanic bulla should be performed before the flush to stage ear disease and help make the decision to perform myringotomy if otitis media is present. Several techniques to clean and flush the ears exist. If myringotomy is performed, the tympanic membrane usually heals within 30 days after the procedure. Deep ear flush and myringotomy are best performed by experienced practitioners with a video-otoscope; therefore, referral to a dermatologist might be ideal.
In most cases of otitis externa, topical therapy alone is sufficient and is preferred when possible. In contrast, chronic, severe cases of otitis externa and otitis media often require additional systemic therapy.
The amount of medication applied is important. Generally, the recommendation is to use about 0. Ear cleaners should be used at home as part of most treatment protocols initially once daily to twice weekly depending on the severity of the otitis and amount of discharge present and as maintenance therapy usually once to twice weekly to help prevent future infections once the otitis and infection are resolved.
However, overcleaning should be avoided because it can contribute to maceration and ear disease. Clients should be educated on the proper technique to clean the ears and to avoid using cotton balls and cotton swabs inside the ears.
Available ear cleaners include drying agents, antiseptics, ceruminolytics, and combination products. Many different acaricidal products may be used to treat infections caused by Otodectes cynotis ear mites and, less commonly, Demodex species. It is important to always use higher volumes or concentrations of topical antibiotics because they may prove efficacious, even when resistance has been suggested on a susceptibility panel.
With topical drugs, concentrations to times superior to the minimum inhibitory concentration may be reached. For Pseudomonas Figure 7 and multidrug-resistant infections, I recommend treating the patient until 1 week past negative cytologic and culture results.
Chronic Pseudomonas otitis. Antibacterial agents: These products are indicated when infection is present and cleansing solutions are insufficient. Most topical antibacterial products also contain glucocorticoids and antifungals.
Numerous topical preparations of variable potencies are available for use in the external ear canal. Most cases of chronic otitis externa benefit from topical glucocorticoids. Glucocorticoids have antipruritic, anti-inflammatory effects and decrease exudation and swelling, thereby helping to reduce pain and discomfort.
In addition, they cause sebaceous atrophy and decrease glandular secretions. Glucocorticoids may reduce scar tissue and proliferative changes, which helps to promote drainage and ventilation. Most ear products contain various combinations of glucocorticoids, antibiotics, antifungals, and parasiticides. Two new veterinarian-administered products containing florfenicol, terbinafine, and mometasone furoate Claro, bayerdvm.
The duration of effect is 30 days for Claro and 7 days for Osurnia. Ears should not be cleaned at home after application. The recommendation is for use in the clinic after ear cleaning, and only with intact tympanic membranes.
These are great options for patients that do not allow topical therapy at home and to improve compliance, with potential benefit for acute or mild otitis cases.
Nao Hensel obtained her doctor of veterinary medicine degree from Colorado State University in She then completed a 1-year rotating small animal internship in Massachusetts followed by a 3-year veterinary dermatology residency in Georgia.
A native of Japan, Dr. Hensel subsequently moved to Basel, Switzerland, where she opened a veterinary dermatology practice in Canine otitis externa is a common dermatologic problem in small animal practice. Affected ears are often painful and pruritic e.
Therefore, the primary causes of the ear problem must be identified, eliminated, or managed long term. Otitis externa is considered a multifactorial disorder; the most common primary cause is allergy, which is often secondarily accompanied by microbial infections Malassezia and bacteria. The diagnostic workup for otitis externa requires a detailed history, thorough physical and ear examinations, and cytologic evaluation. Bacterial and fungal cultures are rarely needed unless systemic antimicrobial therapy is necessary for otitis media.
Diagnostic imaging e. Radiographic findings may be falsely negative, but radiographs may also be a cost-effective option in general practice. Whenever possible, the tympanic membrane should be evaluated for any changes e.
Ear cytology, with Diff-Quik staining, is an effective and quick in-house option to confirm and quantify any type of infection and degree of inflammation and should be performed for all dogs with otitis externa.
Most otitis externa cases can be sufficiently managed by topical therapy; however, otitis is likely to return after topical treatment if the underlying cause e. Before beginning therapy, ensure that the amount of debris in the ear canal is minimal; excessive ear debris should be removed by a deep ear flush. If the ear canals are severely inflamed, the authors recommend pretreatment with systemic anti-inflammatory drugs e.
A thorough ear flush will enable visualization of the tympanic membrane but will also prevent trapping and inactivation of ear medication in the debris. After successful treatment of an ear infection and inflammation, regular ear cleaning at home every 7 to 14 days as needed will also help reduce accumulation of otic material and recurrence of infections. Ear cleaners have different properties e. TABLE 2 lists some of the ear cleaners available on the market. Some cases can be quite painful, and the ear canal can be edematous from the inflammation, which can make an otoscopic examination very difficult, even with the patient under sedation.
The otoscopic examination can be facilitated by giving patients a short course of oral glucocorticoids e. A common cause for acute otitis externa is foreign bodies e. Removing the foreign body will result in a fast recovery and eliminate the need for further treatment in the absence of secondary infection. Ear diseases that have been present for at least 1 month or that recur frequently are considered chronic.
Management of chronic cases is more challenging BOX 1. Although it is important to treat the infections, it is also important to address the inflammation and underlying problem.
Depending on the severity of the inflammation and stenosis, oral glucocorticoids may be needed to reduce ear canal inflammation. A pilot study of 5 dogs indicated that cyclosporine may be another potent anti-inflammatory drug and that it may effectively control chronic otitis, especially with long-term use. Many commercially available topical ear medications contain a combination of antibiotics, antifungals, and glucocorticoids and are supplied in different formulations for daily or weekly applications TABLE 3.
Malassezia yeast organisms are often secondarily present in patients with chronic ear disease. Malassezia otitis typically results in variable degrees of inflammation and excessive, malodorous, mostly brown to dark-brown, waxy discharge.
Of note, however, the number of Malassezia organisms seen during cytologic examination does not always correlate with the severity of clinical signs. Malassezia organisms not only have the ability to increase hyperplasia and secretion by proteins and enzymes they produce but also may be able to trigger an immune response, resulting in severe inflammation and potentially hypersensitive reaction.
Fungal culture is not recommended because Malassezia organisms are usually not resistant to antimicrobials such as azoles, the organism does not grow well on regular fungal culture media, and standardized susceptibility testing is not available.
Uncomplicated Malassezia overgrowth can usually be controlled by regular at-home ear cleaning e. For more severe and chronic cases, the authors prefer to use a topical product containing antifungal medication e. Initially, the ear flush is performed daily until the yeast infection is under control 1 to 3 weeks , followed by once weekly for maintenance. A recent preliminary in vitro study showed that the dexamethasone SP added to several commercially available ear flush products is stable for 21 to 90 days at room temperature.
The normal microflora within the ear canals is characterized by a diverse population of bacteria in phyla such as Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria. In patients with chronic otitis externa, the microbial populations become much less diverse and are dominated by organisms such as Staphylococcus and Pseudomonas , and to a lesser degree by Corynebacterium , Proteus , Lactobacillus , Streptococcus , Porphyromonas , and Enterococcus.
Figure 1. Suppurative otitis with erythema and purulent discharge in an atopic dog with secondary Pseudomonas otitis. As with Malassezia , bacterial ear infections are considered secondary problems; if bacterial infections are recurring, the patient should be thoroughly investigated for primary underlying diseases, such as allergies. Because bacterial otitis externa is treated topically, bacterial culture and sensitivity is often not necessary because susceptibility testing cannot accurately determine resistance for topically applied antimicrobials.
Minimum inhibitory concentration MIC is the lowest concentration of antibiotic that prevents bacterial growth and helps guide susceptibility testing; however, correctly applied topical antibiotics usually reach MICs of up to to fold.
Despite the high MICs, before treatment is started, any debris and purulent discharge must be removed and sufficient ear medication must be applied. The recommended amount is 0. To increase client compliance with treatment, 1-mL syringes can be sent home with clients so that they can draw up the recommended amount of ear medication. Numerous commercially available ear products contain antibiotics or disinfectants with antibacterial activity TABLE 3.
Common antibiotics are aminoglycosides gentamicin, neomycin , fluoroquinolones ciprofloxacin, enrofloxacin, marbofloxacin, orbifloxacin , polymyxins colistin sulfate, polymyxin B , fusidic acid, florfenicol, and silver sulfadiazine.
Many chronic cases of bacterial otitis externa are associated with Pseudomonas organisms; typically effective antibiotics are fluoroquinolones, gentamicin, and polymyxin B. However, treatment can be complicated by development of multidrug resistance as well as the formation of biofilm. These agents weaken the bacterial cell wall and facilitate penetration of the antibiotic into the bacteria.
This action has been demonstrated in vitro for multidrug-resistant Pseudomonas. It is well tolerated and not ototoxic.
❿Treating Otitis Externa in Dogs | Today's Veterinary Practice.
Prednisone for dog ear infection
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Ear infections are a common problem in dogs. Ear infections are not always obvious when looking at the outside of the ears. Dogs will usually scratch at their ears or shake their heads when they have an infection, and you may detect a smell, or see excess wax or discharge in the ear canal. If you notice any of these signs, it is important to take your dog in to see your vet.
Unfortunately ear infections are a recurring problem for some dogs. The following information is intended to give you an understanding of why ear infections occur, and the best way to treat them. There are a number of factors that can predispose a dog to ear infections.
These factors alter the environment in the ear canal, making it more likely to become infected. Common predisposing factors in dogs include:. The conformation of the ear canals, such as narrowed ear canals, the presence of hair, or an abundance of secretory glands.
Certain breeds are more prone to ear problems due to their conformation. Moisture can predispose dogs to ear infections. Increased humidity or swimming can result in increased moisture in the ear canals and maceration of the ear canal, resulting in infection. Trauma from excessive cleaning with ear cleaners or cotton buds, or vigorous hair plucking can also predispose to infection.
There are also primary factors that can directly cause inflammation of the ears otitis externa. The most common primary factors include:. Parasites — ear mites are one of the most common parasites which affect the ears, sometimes they can be seen when your vet examines the ear with an otoscope, but other times we can only identify them by looking under a microscope.
Fleas and ticks are other common parasites which can cause ear problems. Allergies — Atopy is the most common underlying disease in recurring or chronic ear infections.
Atopy is a genetically predisposed condition, where inflamed, itchy skin including the skin lining the ears! Dysfunction of the skin barrier is thought to play a role in this process. Dogs can react to many different allergens and if atopy is suspected further investigation and treatment is required. Food allergies can also commonly result in recurrent otitis externa, and a food trial is recommended. Discharge and odour may be noticeable to people. Bacteria and yeast infections must be treated medically.
Ear infections can be a frustrating, recurring problem, and it is important to treat them properly from the start. To do this we need to know what sort of infection is in the ear, to do proper home care regularly, and to have recheck appointments to ensure that infections have resolved before stopping treatment.
In recurrent cases preventative measures are then put in place to help prevent recurrence. This will help us determine the most appropriate ear drop for your dog. In some cases rod infections we can need to send a sample away to be cultured to determine which treatment to use, as resistance to multiple antibiotics is common with these infections.
It is also very important to thoroughly clean the ear canals, as discharge in the ears will prevent medication from working effectively. In the majority of cases an ear cleaner can be used at home. However, as ear infections can be very painful, a general anaesthetic may be necessary to properly assess and clean the ear canals, and this can be an important part of the treatment process.
Different sized dogs have very different sized ear canals and your vet will advise you on the volume of ear drop required. A course of corticosteroid tablets prednisolone is often required to help reduce the inflammation.
In severe cases we will also need to use oral antibiotics for a minimum of weeks. We need to look into the ear canals with an otoscope to assess the degree of inflammation and discharge in the canal, and we need to repeat the cytology looking at the discharge under a microscope to assess whether the infection is resolving.
It is very important to treat the ears until we do not see any bacteria or yeast on cytology and usually for 1 week after this. For mild cases that respond quickly to treatment days of treatment may be required, in more severe cases at least weeks of treatment is needed. If we do not treat the ears for long enough, we are likely to get recurrence of the problem, and future treatment can be more difficult. Middle ear infection otitis media - If the infection reaches the middle ear, affected animals may have a head tilt, a lack of balance, and unusual back-and-forth eye movements called nystagmus.
These symptoms are called vestibular signs and can indicate a complication of middle ear infection. Aggressive treatment is required in these cases. In this specialist surgical procedure, the entire ear canal is removed and healthy tissue is allowed to grow in.
These procedures are last resorts after severe infection has made effective medical treatment impossible. What factors predispose dogs to ear infections?
Common predisposing factors in dogs include: 1. What primary factors can cause ear problems? The most common primary factors include: 1. Foreign bodies — eg. Grass seeds, dirt, sand, hair can induce irritation. What factors perpetuate ear problems? Treatment of ear infections Ear infections can be a frustrating, recurring problem, and it is important to treat them properly from the start. Helping prevent recurrence 1 Address underlying causes such as allergies 2 If the ear infection is likely to have occurred due to moisture in the ear canals we may recommend a drying agent be used times a week to help prevent recurrence.
Complications of Ear Infection Middle ear infection otitis media - If the infection reaches the middle ear, affected animals may have a head tilt, a lack of balance, and unusual back-and-forth eye movements called nystagmus.
A course of corticosteroid tablets (prednisolone) is often required to help reduce the inflammation. In severe cases we will also need to use. Prednisone does not treat infections. Prednisone reduces the inflammation response and may alleviate the symptoms. But it also suppresses the immune response of. Corticosteroid ear drops are generally used to decrease inflammation, itching and pain. This type of medication may also be used to decrease the amount of. Can prednisone be used to treat ear infections in dogs?. The prednisone will help with the itch and inflammation. The Dem-Otic may treat any Yeats or bacterial infection. You should clean your pet's ears out. What factors predispose dogs to ear infections? Advanced imaging before surgery is ideal. Management of chronic cases is more challenging BOX 1. Ames, IA: Wiley-Blackwell; Nao Hensel obtained her doctor of veterinary medicine degree from Colorado State University in Dark, slimy otic discharge from a dog with Pseudomonas otitis and biofilm.Patrick Hensel is a graduate of the University of Bern, Switzerland. After completing a doctorate thesis and a rotating internship at the University of Zurich, Switzerland, he moved to the United States, where he completed a 3-year veterinary dermatology residency at the University of Georgia in He stayed on as a faculty member until , when he decided to move back to Switzerland to open his own dermatology clinic in his hometown of Basel in Nao Hensel obtained her doctor of veterinary medicine degree from Colorado State University in She then completed a 1-year rotating small animal internship in Massachusetts followed by a 3-year veterinary dermatology residency in Georgia.
A native of Japan, Dr. Hensel subsequently moved to Basel, Switzerland, where she opened a veterinary dermatology practice in Canine otitis externa is a common dermatologic problem in small animal practice.
Affected ears are often painful and pruritic e. Therefore, the primary causes of the ear problem must be identified, eliminated, or managed long term. Otitis externa is considered a multifactorial disorder; the most common primary cause is allergy, which is often secondarily accompanied by microbial infections Malassezia and bacteria. The diagnostic workup for otitis externa requires a detailed history, thorough physical and ear examinations, and cytologic evaluation.
Bacterial and fungal cultures are rarely needed unless systemic antimicrobial therapy is necessary for otitis media. Diagnostic imaging e. Radiographic findings may be falsely negative, but radiographs may also be a cost-effective option in general practice. Whenever possible, the tympanic membrane should be evaluated for any changes e. Ear cytology, with Diff-Quik staining, is an effective and quick in-house option to confirm and quantify any type of infection and degree of inflammation and should be performed for all dogs with otitis externa.
Most otitis externa cases can be sufficiently managed by topical therapy; however, otitis is likely to return after topical treatment if the underlying cause e. Before beginning therapy, ensure that the amount of debris in the ear canal is minimal; excessive ear debris should be removed by a deep ear flush. If the ear canals are severely inflamed, the authors recommend pretreatment with systemic anti-inflammatory drugs e.
A thorough ear flush will enable visualization of the tympanic membrane but will also prevent trapping and inactivation of ear medication in the debris.
After successful treatment of an ear infection and inflammation, regular ear cleaning at home every 7 to 14 days as needed will also help reduce accumulation of otic material and recurrence of infections. Ear cleaners have different properties e. TABLE 2 lists some of the ear cleaners available on the market. Some cases can be quite painful, and the ear canal can be edematous from the inflammation, which can make an otoscopic examination very difficult, even with the patient under sedation.
The otoscopic examination can be facilitated by giving patients a short course of oral glucocorticoids e. A common cause for acute otitis externa is foreign bodies e. Removing the foreign body will result in a fast recovery and eliminate the need for further treatment in the absence of secondary infection. Ear diseases that have been present for at least 1 month or that recur frequently are considered chronic. Management of chronic cases is more challenging BOX 1.
Although it is important to treat the infections, it is also important to address the inflammation and underlying problem.
Depending on the severity of the inflammation and stenosis, oral glucocorticoids may be needed to reduce ear canal inflammation. A pilot study of 5 dogs indicated that cyclosporine may be another potent anti-inflammatory drug and that it may effectively control chronic otitis, especially with long-term use.
Many commercially available topical ear medications contain a combination of antibiotics, antifungals, and glucocorticoids and are supplied in different formulations for daily or weekly applications TABLE 3. Malassezia yeast organisms are often secondarily present in patients with chronic ear disease. Malassezia otitis typically results in variable degrees of inflammation and excessive, malodorous, mostly brown to dark-brown, waxy discharge.
Of note, however, the number of Malassezia organisms seen during cytologic examination does not always correlate with the severity of clinical signs. Malassezia organisms not only have the ability to increase hyperplasia and secretion by proteins and enzymes they produce but also may be able to trigger an immune response, resulting in severe inflammation and potentially hypersensitive reaction.
Fungal culture is not recommended because Malassezia organisms are usually not resistant to antimicrobials such as azoles, the organism does not grow well on regular fungal culture media, and standardized susceptibility testing is not available. Uncomplicated Malassezia overgrowth can usually be controlled by regular at-home ear cleaning e. For more severe and chronic cases, the authors prefer to use a topical product containing antifungal medication e. Initially, the ear flush is performed daily until the yeast infection is under control 1 to 3 weeks , followed by once weekly for maintenance.
A recent preliminary in vitro study showed that the dexamethasone SP added to several commercially available ear flush products is stable for 21 to 90 days at room temperature. The normal microflora within the ear canals is characterized by a diverse population of bacteria in phyla such as Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria. In patients with chronic otitis externa, the microbial populations become much less diverse and are dominated by organisms such as Staphylococcus and Pseudomonas , and to a lesser degree by Corynebacterium , Proteus , Lactobacillus , Streptococcus , Porphyromonas , and Enterococcus.
Figure 1. Suppurative otitis with erythema and purulent discharge in an atopic dog with secondary Pseudomonas otitis. As with Malassezia , bacterial ear infections are considered secondary problems; if bacterial infections are recurring, the patient should be thoroughly investigated for primary underlying diseases, such as allergies.
Because bacterial otitis externa is treated topically, bacterial culture and sensitivity is often not necessary because susceptibility testing cannot accurately determine resistance for topically applied antimicrobials. Minimum inhibitory concentration MIC is the lowest concentration of antibiotic that prevents bacterial growth and helps guide susceptibility testing; however, correctly applied topical antibiotics usually reach MICs of up to to fold.
Despite the high MICs, before treatment is started, any debris and purulent discharge must be removed and sufficient ear medication must be applied. The recommended amount is 0. To increase client compliance with treatment, 1-mL syringes can be sent home with clients so that they can draw up the recommended amount of ear medication. Numerous commercially available ear products contain antibiotics or disinfectants with antibacterial activity TABLE 3. Common antibiotics are aminoglycosides gentamicin, neomycin , fluoroquinolones ciprofloxacin, enrofloxacin, marbofloxacin, orbifloxacin , polymyxins colistin sulfate, polymyxin B , fusidic acid, florfenicol, and silver sulfadiazine.
Many chronic cases of bacterial otitis externa are associated with Pseudomonas organisms; typically effective antibiotics are fluoroquinolones, gentamicin, and polymyxin B. However, treatment can be complicated by development of multidrug resistance as well as the formation of biofilm. These agents weaken the bacterial cell wall and facilitate penetration of the antibiotic into the bacteria.
This action has been demonstrated in vitro for multidrug-resistant Pseudomonas. It is well tolerated and not ototoxic. Biofilm has been recognized as a major virulence factor in chronic infections. It increases antimicrobial resistance by shielding bacteria from the immune system and topical medication. Biofilm is an extracellular matrix i. Figure 2. Dark, slimy otic discharge from a dog with Pseudomonas otitis and biofilm. Figure 3. Neutrophils and bacteria surrounded by thick purple staining filaments and lace-like material in otic discharge from dog with Pseudomonas otitis and biofilm.
Removing biofilm can be challenging; it needs to be broken down physically by thorough flushing and aspiration. In addition, combination of Tris-EDTA and N-acetylcysteine topical product can help to disrupt and liquify the biofilm. Various parasites e. In higher numbers, mites are typically associated with dark-brown, granular coffee-ground exudate.
Chronic ceruminous otitis externa is sometimes caused by Demodex mites. A few topical acaricidal ear preparations containing ivermectin e. However, because many mites and ticks commonly affect other body areas, pesticides with a more systemic or generalized effect are recommended, such as spot-on topicals e. Although treating otitis externa can be challenging, most chronic and recurrent cases can be medically treated and successfully managed, especially when underlying causes are addressed.
Under certain circumstances, a surgical intervention may be necessary, but it should be performed only after all primary causes have been identified and corrected. Because of the severity of chronic otitis and potential involvement of the middle ear, the most effective surgical procedure is total ear canal ablation combined with lateral bulla osteotomy; however, clients must be informed about the potential risks and postsurgical complications.
It is very important to clearly and thoroughly discuss with clients the requirements for successfully managing chronic otitis. Discussions should address the primary causes e. To increase client compliance, show them how to clean and treat the ears, provide detailed written instructions, and schedule follow-up calls, all of which can be done by skilled veterinary nurses.
To increase patient compliance, provide pain control and ensure that ear cleaning and treatment are gently performed. Paterson S, Matyskiewicz W. A study to evaluate the primary causes associated with Pseudomonas otitis in 60 dogs. J Small Anim Pract. Aetiology of canine otitis externa: a retrospective study of cases. Vet Dermatol. Oral cyclosporine in the treatment of end-stage ear disease: a pilot study. Nuttall T. Successful management of otitis externa. In Practice. Chen T, Hill PB. The biology of Malassezia organisms and their ability to induce immune responses and skin disease.
Preliminary study of the stability of dexamethasone when added to commercial veterinary ear cleaners over a day period. Cerumen microbial community shifts between healthy and otitis affected dogs.
Section 2: Otic preparations. Ames, IA: Wiley-Blackwell; — Evaluation of biofilm production by Pseudomonas aeruginosa from canine ears and the impact of biofilm on antimicrobial susceptibility in vitro. Tris-EDTA significantly enhances antibiotic efficacy against multidrug-resistant Pseudomonas aeruginosa in vitro. Glaze MB.
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