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Otitis Externa (Inflammation of the Outer Ear Canal) in Dogs

Occurrence: common
Location of illness: Head/Neck

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Otitis externa is an inflammatory condition of the outer ear canal in dogs that can be triggered by various causes and leads to discomfort such as itching, pain, and possible infections.

The most important facts at a glance

Otitis externa is an inflammation of the outer ear canal in dogs that can be triggered by various factors such as allergies, parasites, and foreign bodies. The L-shaped ear canal provides a moist environment that promotes the growth of microorganisms. Common causes include environmental allergies, food allergies, and ear mites, which are especially common in young dogs. Foreign bodies such as grass awns and excessive moisture from swimming can also promote inflammation. Symptoms include redness, discharge, and foul odor from the ear, as well as itching and pain.

DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made by clinical examination and the use of an otoscopeAn otoscope is a medical instrument used to examine the external auditory canal and the eardrum. Otoscopy is a standard procedure in veterinary medicine for the diagnosis of ear diseases in dogs and cats. to inspect the ear canal. If necessary, a cytological examination of the ear secretions is performed. Treatment depends on the cause and often includes cleaning the ear canal and antimicrobialAn antimicrobial substance is an agent that serves to inhibit the growth of microorganisms such as bacteria, viruses, fungi, and protozoa, or to kill them. Antimicrobials are frequently used to treat infections. drops. In the case of parasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. causes, antiparasitic preparations are used. Allergies may require a long-term management strategy with a hypoallergenic diet and medications. In severe cases, surgery may be necessary.

The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good with early treatment, but chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. problems can occur with recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. inflammation. Preventive measures such as regular ear care and avoiding moisture are important. Research focuses on genetic and microbial causes as well as alternative treatment methods to improve the quality of life of dogs with otitis externa.

Causes

The dog’s outer ear canal is an L-shaped canal that connects the outer ear to the eardrum. This structure provides a moist environment that can promote the growth of microorganisms. The skin in the ear canal is sensitive and can be easily irritated, leading to inflammation. This inflammation can be triggered by a variety of factors, including allergies, parasites, and foreign bodies.

Allergies are one of the most common causes of otitis externa. Dogs can be allergic to environmental allergens such as pollen, house dust mites, and mold. Food allergies are also common and can cause inflammation of the ear canal.

Parasites such as ear mites (Otodectes cynotis) are also a common cause of ear infections, especially in young dogs. These mites feed on skin debris and cause intense itching and irritation.

Foreign bodies, such as grass awns, can enter the ear canal and cause mechanical irritation. Excessive moisture from frequent swimming or improper bathing can also promote the development of otitis externa, as it promotes the growth of bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and yeast.

Another factor can be inadequate ventilation of the ear canal, which is more common in dogs with floppy ears. This anatomical feature can cause heat and moisture to build up, increasing the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

Symptoms

Very common symptoms:

Common symptoms:

Head Tilted to one Side

Dogs with otitis externa often show clear symptoms that can be noticed by the pet owner. The most common signs include intense head shaking and scratching at the ears. This is usually an indicationIndication refers to a valid reason or rationale for using a specific treatment, medication, or medical procedure. It is based on the diagnosis and the patient’s clinical condition. of severe itching and discomfort in the ear canal.

Another symptom is an unpleasant odor coming from the ear. This odor is caused by the accumulation of bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and yeast in the inflamed ear canal. On closer examination, redness and swelling of the ear may also be observed.

There may be discharge from the ear, which can vary depending on the cause of the inflammation. The discharge can be watery, purulentPurulent refers to pus or the production of pus, which may indicate a bacterial infection. Purulent inflammatory conditions are often painful and may have significant swelling and redness., or dark brown, especially if ear mites are involved. In severe cases, the inflammation can be so painful that the dog avoids touching the ear or head.

Some dogs also show general behavioral changes, such as ApathyApathy refers to a state of indifference and reduced interest or lack of emotional involvement in activities or events that would normally arouse interest. or Irritability, due to the ongoing pain and discomfort. In chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. cases, thickening of the skin in the ear canal can occur, which worsens the symptoms.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of otitis externa begins with a thorough clinical examination by a veterinarian. The outer ear is examined for visible signs of inflammation and the presence of discharge.

An important diagnostic tool is the otoscopeAn otoscope is a medical instrument used to examine the external auditory canal and the eardrum. Otoscopy is a standard procedure in veterinary medicine for the diagnosis of ear diseases in dogs and cats., which allows the veterinarian to inspect the ear canal and eardrum. This allows them to identify possible foreign bodies, parasites, or signs of a bacterial or yeast infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

In some cases, a cytological examination of the ear secretions may be performed. This involves examining a smear of the discharge under a microscope to determine the type of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., whether it is bacterial or caused by fungi.

If allergies are suspected as an underlying cause, allergyAn allergy is an overreaction of the immune system to a normally harmless substance, the allergen. The reaction can include symptoms such as skin rash, itching, sneezing, respiratory distress, or in severe cases, anaphylactic shock. testing may be considered to identify specific triggers. Blood tests can also be performed to assess the dog’s general health and rule out other systemic diseases.

Therapy

Treatment for otitis externa depends on the underlying cause. Thorough cleaning of the ear canal is often the first step to remove excess secretions and debris and improve the effectiveness of medications.

AntimicrobialAn antimicrobial substance is an agent that serves to inhibit the growth of microorganisms such as bacteria, viruses, fungi, and protozoa, or to kill them. Antimicrobials are frequently used to treat infections. drops are often prescribed to combat bacterial or fungal infections. These drops usually contain antibiotics and/or antifungals and sometimes anti-inflammatory agents to relieve swelling and pain.

In the case of parasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. causes, such as ear mites, special antiparasitic preparations are used. These agents are usually very effective and lead to a rapid improvement in symptoms.

If allergies are the triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats., a long-term management strategy may be required, which may include a hypoallergenic diet and/or the administration of antihistaminesAntihistamines are medications that block the effects of histamine in the body, thereby alleviating allergic reactions. They are used in dogs and cats to treat Itching, Skin inflammation, and other allergy symptoms. or corticosteroidsCorticosteroids are a class of steroid hormones that occur naturally in the body and can also be produced synthetically. They have anti-inflammatory and immunosuppressive properties and are used in veterinary medicine to treat a variety of conditions. to control the inflammation.

In severe or chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. cases, surgical intervention may be required. Procedures such as laser ablation or complete removal of the ear canal may be considered to achieve permanent relief.

Prognosis and follow-up care

The prognosis for dogs with otitis externa is generally good if the condition is detected early and treated appropriately. Most cases respond well to treatment, and symptoms can be significantly improved within a few weeks.

However, dogs that suffer from recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. ear infections tend to develop chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. problems. In such cases, long-term care and management are required to prevent further flare-ups and maintain ear health.

With correct diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for complete recovery is favorable, unless there is an underlying chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. condition such as a severe allergyAn allergy is an overreaction of the immune system to a normally harmless substance, the allergen. The reaction can include symptoms such as skin rash, itching, sneezing, respiratory distress, or in severe cases, anaphylactic shock. or an autoimmune disease that affects the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body..

Prevention

Preventive measures are crucial to minimize the risk of otitis externa in dogs. Regular ear care, including gentle cleaning with appropriate products, can help prevent the accumulation of dirt and earwax.

Dogs with a tendency to ear infections should be checked regularly for signs of problems. Especially in dogs that swim or bathe frequently, care should be taken to dry the ears thoroughly afterwards to remove excess moisture.

In dogs with known allergies, it is important to reduce allergenAn allergen is a substance that can trigger an allergic reaction in sensitized individuals. These reactions vary in intensity and can range from mild symptoms to severe, life-threatening conditions. exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. as much as possible. This can be supported by special diets or the use of air purifiers and hypoallergenic detergents in the household.

Regular veterinary check-ups are also important to detect and treat potential problems early before they lead to severe inflammation. Close cooperation with the veterinarian can help to develop an individual preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. plan that is tailored to the specific needs of the dog.

Outlook on current research

Much of the current research on otitis externa in dogs focuses on identifying and treating the underlying causes of the disease. Scientists are investigating the role of allergies, particularly food allergies and atopic dermatitis, which are often considered triggers for inflammation of the outer ear canal. Genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. also plays a role, and researchers are working to identify specific genetic markers that may make dog breeds more susceptible to ear infections.

Another important area of research is the study of the microbiota of the outer ear canal. Scientists are analyzing the microbial composition to better understand how certain bacteria and yeasts disrupt the balance and lead to inflammation. This research could lead to more targeted treatments that restore and maintain microbial balance.

ResistanceResistance refers to the ability of microorganisms to withstand the effects of antibiotics, antifungals, or other antimicrobial drugs. Resistance can also refer to the body's ability to be insensitive to diseases or toxins. to antibiotics is another serious issue. Researchers are investigating alternative treatment approaches, such as the use of probiotics and phytotherapeutics, to circumvent the resistanceResistance refers to the ability of microorganisms to withstand the effects of antibiotics, antifungals, or other antimicrobial drugs. Resistance can also refer to the body's ability to be insensitive to diseases or toxins. problem. These alternative therapies could not only be effective against infections, but also reduce the risk of side effects.

Innovative diagnostic methods are also a focus of research. New technologies, such as non-invasive imaging diagnostics, could make it possible to diagnose ear infections earlier and more accurately. Such advances could help improve treatment outcomes and reduce the risk of chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. disease.

Overall, current research aims to develop a more comprehensive understanding of the causes and mechanisms of otitis externa in order to develop preventive measures and more effective therapies. By combining genetic, microbial, and environmental studies, researchers hope to significantly improve the quality of life of dogs with this common condition.

Frequently asked questions (FAQs)

What is otitis externa in dogs? Otitis externa is an inflammation of the outer ear canal in dogs. It can be caused by various factors such as allergies, parasites, bacterial or yeast infections. The disease is common and affects dogs of all breeds and ages.
What symptoms does a dog with otitis externa show? Common symptoms include itching, redness, swelling, discharge from the ear and an unpleasant odor. Dogs tend to scratch their ear or shake their head, which indicates discomfort or pain.
How is otitis externa diagnosed in dogs? The veterinarian examines the dog’s ear thoroughly, often with an otoscopeAn otoscope is a medical instrument used to examine the external auditory canal and the eardrum. Otoscopy is a standard procedure in veterinary medicine for the diagnosis of ear diseases in dogs and cats., to assess the inflammation. In addition, swabs can be taken to determine the type of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and select the appropriate treatment.
What treatments are available for otitis externa in dogs? Treatment depends on the cause. It may include cleaning the ear canal, topicalTopical refers to the direct application of medications or treatments to the skin or mucous membranes for a local effect, without being absorbed into the body. medications, antibiotics, or antifungals. Special diets or antihistaminesAntihistamines are medications that block the effects of histamine in the body, thereby alleviating allergic reactions. They are used in dogs and cats to treat Itching, Skin inflammation, and other allergy symptoms. may also be used for allergy-related inflammation.
Can dogs with otitis externa swim? It is advisable to avoid swimming until the inflammation has subsided, as moisture can worsen the problem. After swimming, the ear should be dried thoroughly to prevent moisture accumulation.
Can otitis externa in dogs become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time.? Yes, if the underlying causes are not treated, otitis externa can become chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time.. RecurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. infections often lead to permanent changes in the ear canal, which can make treatment more difficult.
How can I prevent otitis externa in my dog? Regular cleaning and checking of the ears, especially in dogs with floppy ears, can help prevent ear infections. Also, checking for parasites and avoiding allergens are important preventive measures.
Which dog breeds are particularly susceptible to otitis externa? Breeds with long, floppy ears such as Cocker Spaniels, Basset Hounds, and Golden Retrievers are particularly susceptible. Dogs with allergies or skin problems also have an increased risk of ear infections.
Can otitis externa be transmitted to humans? Otitis externa itself is not contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious., but certain infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. agents could theoretically be transmitted from dog to human under special circumstances. However, this is very rare and can usually be avoided by good hygiene practices.
What happens if otitis externa in dogs is left untreated? Untreated otitis externa can lead to pain, chronicity, and even spread of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. to the middle ear. In severe cases, this can impair hearing or lead to a systemic infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..