Disorders of the Outer Ear in Dogs
A variety of skin conditions affect the outside part of the ear, called the pinna. Most conditions cause tissue changes elsewhere as well. Rarely, a disease affects the outer ear alone or affects it first. As with all skin conditions, a diagnosis is best made when combined with the results of a thorough history, a complete physical and skin examination, and carefully selected diagnostic tests.
Insects and parasites commonly cause inflammation of the pinna—resulting in redness, swelling, itching or blistering—either through direct damage from the bite of the parasite or as a result of hypersensitivity. Tiny skin mites burrow under a dog’s skin, often on the edges of the ears, and can cause intense itching. Because they are so hard to see and find, a veterinarian might take several skin scrapings before making a diagnosis. The type of insect or parasite that is causing the inflammation varies depending on the season, environment, and geographical location. They include ticks, mosquitoes, flies, and fleas. Treatment includes controlling the insects or parasites in the environment, insecticides, repellents, and medications to reduce inflammation and itching.
Canine juvenile cellulitis is an infection and inflammation of the tissues beneath the skin of young dogs. It is an uncommon disorder of puppies and is characterized by masses of small, round raised areas of inflamed skin filled with pus on the face and ears. The lymph nodes below the lower jaw are usually noticeably enlarged. It occurs in puppies 3 weeks to 4 months of age and rarely in older animals. Golden Retrievers, Gordon Setters, and Dachshunds appear to be at greater risk than other breeds. An inflamed, pus-filled, raised area of the skin of the ear canal is common, along with swollen, thickened pinnae. Some dogs will also stop eating, be lethargic, or have a fever. Early treatment is recommended to avoid scarring. Careful observation of the condition of your puppies will help you detect any masses or lumps on their faces or ears. Any lumps or masses, even small ones, are a good reason to take your puppy in for a checkup as soon as possible.
Allergies caused by environmental allergens (such as dust mites, pollens, or molds) or food are common in dogs and frequently cause redness and itchiness of the ears. Allergies often lead to ear canal infections, which can extend to the pinna (outer ear). Other parts of the body (face, armpits, groin, and feet) are also often affected. Veterinarians diagnose allergies based on the dog's signs and history and by ruling out other causes. Food allergies are diagnosed or ruled out with a strict diet trial, which must adhere closely to the veterinarian's directions. Therapy includes "allergy shots" (called allergen-specific immunotherapy), treatments for skin and ear infections, diet changes, and medications. Allergies are longterm conditions that usually require life-long management.
In some dogs, the inner, hairless side of the pinna can become inflamed and irritated after the application of certain ointments or medications. This inflammation, called contact dermatitis, can develop 1–7 days after starting a treatment. The skin of the pinna can become red and swollen and have bumps or sores. Some dogs will also be itchy or in pain. Veterinarians typically treat the condition by stopping all ointments or other topical medications. Switching to a new ointment is unlikely to help, because most products contain similar inactive ingredients.
Ear hematomas are fluid-filled swellings that develop on the inner surface of the ear flap in dogs. The cause for their development is unknown, but head shaking or ear scratching due to itchiness is usually involved. In dogs, the condition is seen with environmental or food allergies in which the ear canals are the primary sites of allergic inflammation and itching. Treatment usually involves surgery to drain and flush the swellings. Frequently, the veterinarian will place a drain made out of a soft tube in the area to help prevent fluid from building up again. Medications may also be prescribed.
Insect bites from mosquitoes, flies, and fleas can cause inflammation of the skin (dermatitis) of the ear. It is a worldwide problem that varies with the season and environment. It typically affects dogs, cats, and horses. The insect bite causes small, hard, round bumps and raised, reddened areas with central bloody crusts that itch. Tissue changes are found on the tips or on the folded surface of the outer ears of dogs with flopped ears. Treatment includes fly repellents, controlling the fly population with environmental clean up (such as removing manure), and insecticides. Medications are also sometimes necessary.
Frostbite may occur in dogs poorly adapted to cold climates and is more likely in wet or windy conditions. It typically affects body regions that are poorly insulated, including the tips of the ears, feet, and tail. The skin may be pale or red, swollen, and painful. In severe cases, tissue death and shedding of the tips of the outer ears may follow. Treatment consists of rapid, gentle warming and supportive care. Amputation of affected regions may be required but should be delayed until the extent of living tissue is determined.
Several ear edge skin disorders characterized by hair loss (alopecia) occur in dogs. Periodic loss of hair on the outer ear in Miniature Poodles involves the loss of hair on the outward curving surfaces of the ear. The hair loss starts suddenly and progresses over several months, but hair may spontaneously regrow. There are no other signs. Treatment is unnecessary.
Hair loss on the outer ear (pattern baldness) has been reported in Dachshunds, Chihuahuas, Italian Greyhounds, and Whippets and is thought to be hereditary. The hair coat begins to thin when a dog is less than 1 year old, and complete hair loss on the outer ear may occur by 8 to 9 years of age. Other commonly affected areas are the neck, chest and thighs. There are no other signs. No effective treatment has been reported, but certain drugs may be helpful.
Hair loss with significant darkening of the skin (hyperpigmentation) occurs on both pinna and the bridge of the nose in Yorkshire Terriers and Doberman Pinschers. The tail and feet may also be affected. It is usually first noticed when the dog is between 6 months and 3 years old, and the condition worsens as the dog ages. The hair loss does not usually resolve, and there is no treatment.
Several immune-mediated diseases (such as pemphigus foliaceus, pemphigus erythematosus, drug reactions, toxic epidermal necrolysis, and vasculitis) may affect the outer ear and the ear canal. Other areas of the body are typically affected and may include footpads, mucous membranes, skin and mucous membrane junctions, nails and nail beds, and the tip of the tail. Immune-mediated diseases are confirmed using biopsies of primary lesions.
Sarcoptic mange is an infectious skin disease caused by a parasitic mite that burrows into the top layers of the skin. It is common in dogs throughout the world. The condition begins with small, red, round bumps on the skin. These bumps can progress to scaling, crusting, and raw, irritated open sores on the ear edges and other parts of the body as a result of scratching; however, in some cases only the red bumps and itching are seen. Itching is severe. Transmission of the mite is by direct contact with infected animals or contaminated objects (such as bedding).
Diagnosis is based on signs, history of exposure, and discovery of mites on multiple skin scrapings. Treatment options include dips, injections, and spot-on and oral medications. Your veterinarian will be able to prescribe the best therapy for your pet. Because mites can survive off the host for a variable amount of time, all bedding, brushes, and objects in your pet’s environment should be thoroughly cleaned. Because these mites are highly contagious, other household animals should also be treated.
Overly oily skin at the edge of the ear (seborrhea) is common in Dachshunds, although other breeds with ears that hang loose may be affected. The tips of the ears on both sides are usually affected, but the condition can progress to involve the whole ear edge. The cause is unknown. Signs include waxy gray to yellow scale sticking to the base of hair shafts. Plugs of hair can be easily pulled out, leaving behind skin with a shiny surface. In severe cases the ear edges are swollen and cracked. Treatments are available and can be prescribed by your veterinarian.
Sebaceous adenitis is an uncommon skin disorder of dogs that involves inflammation and destruction of the sebaceous glands (glands in the skin that produce oils). The most commonly affected breeds are Standard Poodles, Akitas, Samoyeds, Vizslas, Havanese, Springer Spaniels, and Lhasa Apsos. Signs include hair loss and scales that stick to the hair shafts on the pinna (outer ear), forehead, face, tail, and body. Itchiness, when seen, is usually associated with a secondary skin infection. The condition is diagnosed with a tissue biopsy. Treatment includes medications and medicated shampoos. Your veterinarian may make additional recommendations to increase the effectiveness of bathing routines.
Tissue death of the pinna can occur due to blood clots that form within blood vessels. The decreased blood flow to the area causes open sores to form, with scaling, thickening, and darkening of the surrounding skin. Skin changes start at the tip of the pinna and then spread along its inner surface. Medications can help some affected dogs, but surgery to remove the diseased tissue may be necessary. The cause is unknown.
Auricular chondritis is inflammation of the cartilage within the external ear. It occurs rarely in dogs. Signs include pain, swelling, redness, and deformed pinnae. Both ears are usually affected. Some dogs will also have signs in other parts of the body, including the joints, eyes, and heart. Treatment may not be necessary if the dog is not in pain and if only the ears are affected. Medications may help dogs with pain or with signs in other parts of the body. With or without treatment, the pinnae will be permanently deformed.
Vasculitis is inflammation of the blood vessels, an uncommon disorder in dogs. The skin of an affected area develops purple spots, redness, sores, and scabs. Shedding of dead tissue can also occur. Vasculitis typically affects the pinnae, tail, and footpads. An inappropriate immune system response, drugs, infections, or cancer can cause the disorder; however, the cause may be unknown or difficult to identify. Treatment involves eliminating any known cause as well as medication to reduce the effects of the immune system.
Nodular granulomatous dermatitis refers to inflammation of the skin that results in the formation of small lumps (nodules). If no infectious organisms are identified within the affected tissue, these nodules are described as sterile. Great Danes and Rottweilers have an increased risk for forming these sterile, inflammatory nodules on the edges of the ears. In some parts of the world, the protozoa that causes leishmaniosis might be responsible. Your veterinarian will prescribe medications to treat the condition and keep it under control.
Ticks can cause irritation at the site of attachment and may be found on the pinna or in the ear canal. The ear tick, found in the southwestern United States, South and Central America, southern Africa, and India, is a soft-shelled tick whose younger, immature forms infest and live on the external ear canal of dogs and other animals. Signs of infestation include head shaking, head rubbing, or drooped ears. Both the animal and the environment should be treated. Your veterinarian can recommend the most appropriate treatment for your pet and your local area.
Also see professional content regarding diseases of the pinna.