by: Dr. Cindy Krane
Otitis refers to an inflammation of the ear; externa refers specifically to the external part of the ear; combined they equate to ear infections. To your Golden, ear infections are painful and bothersome. To owners they result in numerous visits to vet, and are costly and frustrating to treat. To many golden owners it seems like as soon as one ear infection has resolved another starts up. The reason that ear infections are chronic and recurrent is that they are caused and compounded by many factors. Chronic irritation in the ear canal causes the glands that line the canal to enlarge (become hyperplasic) and produce excessive amounts of waxy exudate. Over time the skin in the canals and on the inside of the earflaps becomes thickened and fibrotic. Consequently the width of the ear canal is reduced. The canal becomes calcified and narrower, making it more difficult to establish drainage of the waxy exudate. The exudate builds up and causes additional irritation, which in turn causes increased production of exudate and further reduces the diameter of the canal. The more irritated the canal then less able we are to remove exudates and effectively apply medication, thus the canal continues to be irritated and to lay down thicker, more fibrotic tissue. It becomes a vicious cycle. Once this pattern is set up and the process is in motion, it becomes very difficult to cure an ear infection. In order to treat and ideally cure the ear infection you must first determine the root of the problem. The majority of ear infections are secondary to some to underlying cause. The unique shape of the dogs’ ear canal predisposes them to ear infections. Rather than being straight (like people) the dogs’ canal starts off vertically then makes a sharp right angle becoming the horizontal ear canal. Wax and debris have a difficult time traveling up this L shaped maze. Other contributing factors include the shape of the earflap (pinnae). Pendulous, long, floppy eared dogs (think basset hounds, poodles, retrievers) get far more ear infections than erect ear dogs (think Doberman). Some dogs have concurrent, underlying illness including hormonal imbalances (hypothyroidism or Cushing’s), generalized skin disease, or allergies (inhalant, contact, or food). Life style and environmental factors, like humidity, moisture, warm weather, swimming, and grooming influence a dog’s risk of ear infections. Excessive amounts of hair, foreign material, polyps, or neoplasia can occlude the canal and cause obstructive disease. Parasites including ear mites can cause extreme itching in the ear canal. In fact anything that irritates and inflames the canal leads to an over production of exudate. In turn the exudate results in further inflammation. Ear infections represent one of the most common problems for which owners seek veterinary attention. Goldens are prone to and plagued with them. Ear infections in dogs are not akin to ear infections in children. They are unlikely to be accompanied by a cold or respiratory infection, and are rarely contagious or infectious. They occur primarily as a sole entity but occasionally progress to otitis media or interna. The deeper the affected structures the more severe the resulting clinical signs; problems with equilibrium, balance, facial nerve paralysis, and deafness can be caused by ear infections. The clinical features of otitis externa include the dog’s excessive scratching at the ears, rubbing or shaking the head, and vocalizing or showing other signs of pain when the ears are touched. Upon further examination redness, swelling, exudate, and a pungent odor may also be noted. The diagnosis of otitis externa is based largely on the history, clinical signs and analyzing the discharge. The gross appearance of the aural (ear) discharge helps determine if the infection is bacterial (thin, brownish black or creamy white to tan colored discharge), parasitic (dry black, flakey discharge), or caused by yeast (thick, tan, yellow discharge). Cytology, while not particular complex nor expensive is a very valuable tool used to diagnose and treat otitis externa. A sample of the exudate from the horizontal ear canal is taken with a swab and examined microscopically. Ear mites, bacteria, yeast, white blood cells, or wax can be detected. The initial treatment is based on this evaluation of the aural exudate. Additional diagnostics include bacterial culture and sensitivity of the discharge. This enables the infection to be treated with an antibiotic that will be most effective at eliminating the organism causing the infection, which is particularly useful in chronic severe infections. Most common pathogens isolated from ear infections are staph, pseudomonas, and malassezia (yeast). Occasional imaging including radiographs, CT or MRI can be used to visual the surrounding structures and the extent of the ear disease. Bloodwork may be helpful in diagnosing underlying diseases, allergies, and thyroid deficiency. Intradermal allergy testing may be beneficial in a large amount of patients as underlying allergies are prevalent. Sedation or general anesthesia may be indicated in the work up of otitis externa. It provides for pain relief, ensures the patient does not move, and allows for visualization of the eardrum and thorough cleaning of the ear canal. Medical management is the treatment of choice for otitis externa. Cleansers, topical and systemic antibiotics and anti-inflammatory medications are often used in varying combinations. Infected ears must be flushed out with cleansers, cleaned of excess exudate and thoroughly dried. That ensures that when the medication is applied it can be effectively delivered and not merely rest on top of built up exudate where it will be of little to no value. Most cleansers contain a mixture of alcohol and acids. Some people even mix up there own solution of vinegar and alcohol. Some are designed to change the acidity within the ear canal so that the environment is not conducive to infections. Others act as buffers and weaken the bacterial cell walls, allowing the meds to be more efficacious. Cleaning and drying agents must may used during active infections daily and once to twice weekly thereafter for maintenance. Be careful if using cotton swabs not to push exudate deeper into the canal. Cleansers are most often followed by ointment, creams, salves that deliver the medication directly into the site of the problem. These topical medications are the main stay of treatment for otitis externa. They frequently contain a mixture of antibacterial, antifungal, antiparasitic agents combined with corticosteroids. The product may include silvadene, a wound cream with antibacterial properties. In addition to cleansers and topical medication, some infections require oral medication. This attacks the problem from the inside out while the ointments continue to work from the outside in. Corticosteroids provide anti-inflammatory properties to decrease the swelling and open up the ear canal. This allows for increased drainage, more precise application of topical medications, and decreased secretions, pain, itching, proliferation, and stenosis. Antihistamines and other immunosuppressant (Atopica) provide similar benefits. Antibiotics may also be used for severe, deep, recurrent bacterial infections. Additional treatment modalities include hyposensitivzation vaccine (allergy shots), hypoallergic diet, sedated deep ear flushing and even surgical intervention. Surgery is centered around establishing draining by resecting or even removing the entire canal. While expensive and invasive, surgery can provide a definitive treatment and cure many patients. They go on to live pain free without any further need for ear medications. Ear infections unfortunately tend to be chronic and recurrent. Many times medical management fails and the problem re-occurs. It may be that the original infection was not treated aggressively enough, for long enough, or with the appropriate choice of medications. Many times the owner is non-compliant and unable to properly cleanse the ear or apply the ointment. The most likely scenario resulting in treatment failure is that the underlying cause was not determined, address and resolved. Just cleaning the discharge out and using some ointment is unlikely to cure the infection. It is like putting Band-Aid on a wound that really needs stitches. Try keep your Golden’s ear free of pain and infection, be sure to clean thoroughly and frequently, administer medications as directed, and follow up with recheck examinations with your veterinarian. Develop a maintenance plan to decrease the frequency and severity of infections.