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Dog ear infections require close cooperation with your vet to treat successfully.
Dog ear infections are often caused by a yeast called MMalassezia Pachydermatitis. Â Malasezzia yeasts live on normal dog skin, but some dogs get overgrowths of the yeast on their skin which causes symptoms such as thickening, scaliness, redness and itchiness of the skin.
Malassezia Yeast Infections in Dogs and Cats
Oct 9, 2010Â Lorie Huston
Yeast are, by definition, a spore-like form of fungi. Malassezia is a yeast organism that frequently populates the skin of the dog and cat. In fact, Malassezia are present even on the skin of healthy dogs and cats. However, when the skin becomes damaged, the changes in the skin give the yeast the opportunity to reproduce and infect the skin in higher numbers. The yeast organisms can infect the ears of the dog and cat as well.
Malassezia Yeast Infections in Dogs and Cats
Yeast infections involving Malassezia rarely occur in either dogs or cats without an underlying form of skin disease. Though the organisms are capable of causing disease in damaged skin, they are not particularly virulent in the absence of pathology.
Yeast infections due to Malassezia occur frequently in dogs and can occur in cats but are less common in the feline species.
Any type of skin disease can predispose a dog or cat to a Malassezia yeast infection. Some of the more common predisposing causes are:
- flea allergies
- food allergies
- inhalant allergies (also known as atopy)
- seborrhea
Other diseases that affect the skin can sometimes be responsible for causing Malassezia yeast infections also. These diseases include demodectic mange, autoimmune skin disease and other types of skin disease.
Symptoms of Canine and Feline Malassezia Yeast Infections
The most common and easily recognizable symptom of yeast infection in dogs and cats is intense itchiness.
Malassezia can infect both the skin and the ears of the canine and feline. In dogs, yeast infection with Malassezia is an extremely common secondary infection. Yeast infection is less often diagnosed in cats but in either species, infection can be problematic. Without treatment of the yeast infection, the underlying disease is unlikely to respond well.
Commonly seen symptoms are those seen with many other skin diseases and include reddened or inflamed skin, open sores, scabs, hair loss and, in more chronic cases, thickened skin. Yeast infections often cause a foul skin odor as well.
In the ears, Malassezia yeast infection causes similar symptoms. The dog may shake his head, scratch at his ears or tilt his head. The ears may have a black to brown colored waxy discharge and may also have an odor.
Treatment of Malassezia Yeast Infections in Dogs and Cats
Yeast infection with Malassezia is treated in several different ways. Shampoos are frequently used although they may not be totally effective in and of themselves. Commonly used shampoos include benzoyl peroxide shampoos and those containing chlorhexidine. In addition, shampoos containing anti-fungal medications such as miconazole and ketoconazole may be used as well.
Topical medications used to treat small lesions include those containing acetic acid. A mixture of vinegar and water is often used to treat small areas of yeast infection also.
Antifungal medications such as ketoconazole given orally are usually the most effective means of treatment.
Any time a dog or cat develops a skin disease, secondary infection with Malassezia yeast is a possibility. When this occurs, your dog or cat may not improve until the yeast infection is controlled. Your veterinarian can perform simple skin tests to determine if your pet has a yeast infection.
Dog ear infections are commonly caused by the budding yeast Malasezzia pachydermatitis. Â Dog ear yeast infections are characterised by a yeasty smell, often with thickened skin, redness, scaling and a thick discharge inside the ears. Â Dog ear yeast infections are usually long term problems and won’t be painful initially. Â While they can be hard to treat, they can be prevented by good ear hygeine and attention to your dogs overall health and other skin problems.
Malassezia (yeast) infections: something extremely common in cats and dogs, especially during allergy season. These little buggers can cause nasty ear infections, and if you look for them properly, can be found anywhere on the skin.Â
Incidentally, our microscope in the clinic is suberb, but not an electron microscope (as what has taken this image).
Otitis externa, or inflammation of the external ear canal, is a common condition in dogs. It is characterized by inflammation of the soft tissue components of the external ear canal and is particularly prevalent in dogs with long, floppy ears. Otitis externa may affect 20 percent of dogs.  Â
Left: as demonstrated by the above ear-model, the ear canal has a vertical and a horizontal component. This predisposes the dog to ear infections as debris must work its way upward rather than straight out.Â
Right: otitis externa with brown exudate Anatomy of the earÂ
The ear of the dog and the cat is composed of three parts: the external ear, the middle ear and the inner ear. Together these components allow the animal to locate a sound and the direction from which it emanates, to orientate the head in relation to gravity and to measure acceleration and rotation of the head.Â
Selective breeding, of dogs in particular, has resulted in a wide variation in relative size and shape of the components of the external ear. Compare, for example, the French Bulldog, the Cocker Spaniel, the German Sheperd Dog, the St. Bernard and the Persian cat. The pinnal shape and carriage, the diameter of the external ear canal, the degree of hair and amount of soft tissue within the external ear canal, and the shape of the skull within which the middle and inner ear lie vary from one breed to another. The external ear canalÂ
An importrant difference between the tissues of healthy ears and infected ears is the appaerance and distribution of the glandular structures. In a healthy ear, sebaceous glands are usually numerous , large and actively secreting. In chronic otitis externa, they are less active and much smaller. The external ear canal may normally contain a small amount of wax that is yellowish-brown in color. Signs of ear disease
Every day we see dogs who have problems with their ears. Signs of these ear problems include:Â
⢠OdorÂ
⢠Scratching or rubbing of ears and headÂ
⢠Discharge in the earsÂ
⢠Redness or swelling of the ear flap or canalÂ
⢠Shaking of the head or tilting it to one sideÂ
⢠Pain around the earsÂ
⢠Changes in behavior such as depression or irritability Causes of ear diseaseÂ
â¢Â Allergies such as atopy or food allergiesÂ
â¢Â Parasites - ear mites. Adult mites are large, white and free-moving. the life cycle of the ear mite is three weeks. Mites are characterized by thick, reddish-brown or darkbrown exsudate and crusts in the ear. Ear mites are the single most frequent cause of otitis externa in the cat. Mites are highly contagious.Â
â¢Â Bacteria and Yeast infections. Staphylococcus or Streptococcus (Gram-positive bacteria) infections are most frequently associated with acute otitis externa. There is a light-brown, creamy exudate. Gram-negative organisms (Proteus, Pseudomonas, E.Coli) are most frequently observed in chronic otitis externa or recurrent ear disease. There is a yellow exudate. Malassezia canis is a budding yeast: a brown, waxy adherent exudate.Â
â¢Â Ticks. The spinous ear tick is found in the external ear canal of dogs and cats. The ear canal become packed with immature ticks. Treatment involves mechanical removal, spraying or dipping the coat with an insecticide.Â
â¢Â Foreign bodies, e.g., plant awnsÂ
â¢Â TraumaÂ
â¢Â Hormonal abnormalities, e.g., hypothyroidismÂ
â¢Â The ear environment, e.g., excess moisture and ear anatomyÂ
â¢Â Hereditary or immune conditionsÂ
â¢Â Tumors TreatmentÂ
The first step in otitis externa is a thorough cleansing of the ear canal followed with irrigation of the canal with a warm antiseptic solution (chlorhexidine or betadine). A warm sterile solution should be used if there is any indication of ruptured membrane.Â
Most topical ear medications are combinations containing one ore more antiparasitics, antibacterial, antimycotic, anti-inflammatory, local anesthetic, ceruminolytic and drying and cleaning agents. Oil or ointment bases help moisturize the skin and are effective in dry, scaly or crusty lesions. Solutions or lotions are most frequently used in exsudative ear lesions.Â
Cotton applicator swabs can be used to clean the inside of the earflap and the part of the ear canal you can see. They should NOT be used farther down in the ear canal since that tends to pack debris in the ear canal, rather than removing it!Â
Chronic otitis externa is usually associated with underlying skin conditions such as seborrhea, hypothyroidism or improperly or neglected ear disease.ar problems caused by a systemic disease such as a hormone abnormality or allergy must include a therapy that treats the whole dog, such as hormonal replacement or allergy testing and hyposensitization (immunotherapy). Surgical treatmentâ¨Depending on the severity of the problem, the vertical canal may need to be opened surgically. This enables debris to be removed more effectively. This is done to prevent severe scarring after prolonged specific medical therapy has been ineffective. This procedure is called a lateral ear resection, Zepp procedure, or LaCroix procedure. Â
If the canal becomes so scarred that it is practically closed, ablation may be the final option. In this surgical procedure, the entire ear canal is removed and healthy tissue is allowed to grow in. This procedure is a last resort after severe infection has made effective medical treatment impossible. A specialist is called in for these cases and although surgery is expensive, dogs with chronic severe otitis usually require no further ear treatment for the rest of their lives. Â
Aural hematomaÂ
Complication of ear disease:Â aural hematomaÂ
When a dog with uncomfortable ears shakes and scratches vigorously, a blood vessel in the ear flap may rupture. This leads to bleeding into the tissues of the pinna (see above illustration). The usual recommendation is to have the blood clots removed and the ear bandaged and cleaned under anesthesia. If the hematoma is not so big as to occlude the ear canal (thus preventing medication), the option to forgo surgery exists; but without surgery, the ear may scar down into an abnormal appearance. Preventing ear disease
The key to healthy ears is to keep them clean. Check your dogâs ears weekly. A slight amount of waxy buildup may be present in normal ears. If your dog swims a lot, has pendulous ears, or a history of ear disease, routine cleaning (often once to three times per week) is recommended. Use the same procedure as described above. Excess hair around the ear can be clipped to allow more air flow. Treat any underlying condition that predisposes your dog to ear problems.Â
Remember, if your dog is showing severe discomfort, the ears have a bad smell, or the ear canals look very abnormal, do not delay in contacting your veterinarian. If your dog has a ruptured or weakened eardrum, some ear cleansers and medications could do more harm than good.Â
Dog ear infections need to be diagnosed by a vet. Â The cause of the problem will influence the treatment, and the wrong treatment can delay recovery or even make the problem worse.
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