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Malassezia Pachydermatis (Fungal Infection of the Skin) in Dogs

Occurrence: common
Location of illness: General/Whole body, Skin/Fur

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

Malassezia pachydermatis is a yeast that commonly colonizes the skin and ears of dogs and can cause an 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. under certain conditions. This fungal 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., also known as Malassezia dermatitis, occurs when the yeast multiplies excessively and causes an inflammatory reaction.

The most important facts at a glance

Malassezia pachydermatis is a yeast that lives on the skin of dogs and normally causes no problems. Problems arise when the fungus multiplies excessively, often due to a weakened 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., allergies, skin irritations or injuries. Certain dog breeds are more susceptible due to genetic factors. Symptoms include skin redness, hair loss, oily and scaly skin, and an unpleasant odor. 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 tests, such as cytologycytology is the study of cells, their structure, function, and chemistry. In medicine, it often refers to examining cells under a microscope for diagnosis of diseases., in which skin or ear swabs are examined microscopically.

Treatment often includes antifungalAntifungal means effective against fungal infections. Antifungal medications are used to treat infections caused by fungi by inhibiting their growth or reproduction, or by killing them. medications, either topically in the form of shampoos or creams, or systemically with medications such as itraconazole. It is important to treat the underlying causes to prevent recurrence. 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 if the condition is recognized early, but a long-term management strategy is necessary for 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. Preventive measures include regular grooming, control of allergies, and a balanced diet to promote skin health. Research focuses on developing new treatments and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies to improve the well-being of dogs.

Causes

Malassezia pachydermatis is a lipophilic yeast that naturally occurs on the skin surface of many animals, including dogs. In a healthy state, it is part of the normal skin flora and causes no problems. The yeasts are oval to spherical and reproduce by budding. Their growth is favored by the presence of lipids produced on the skin by sebaceous glands.

The causes of excessive proliferation of this fungus are varied. Often a weakened 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. or an 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. is 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.. Skin irritations or injuries, hormonal disorders, moist skin environments, or excessive sebumsebum is the oily substance produced by the skin's sebaceous glands. It helps keep the skin and hair supple and provides some protection against bacteria and fungi. production can also promote proliferation. Certain breeds, such as Basset Hounds, Cocker Spaniels, and West Highland White Terriers, are more susceptible to this condition due to their 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..

Another significant risk is the presence of underlying conditions such as atopic dermatitis, seborrhea, or endocrine disorders. These conditions create an environment in which Malassezia can thrive by weakening the skin barrier or impairing the dog’s normal immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens..

Symptoms

Very common symptoms:

Common symptoms:

The most common symptoms of a Malassezia 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. include skin redness, itching, and scaly skin. Affected dogs often scratch intensely, which can lead to further skin injuries and infections. The skin may develop a greasy or oily film and smell unpleasant.

Ear infections are also common, with affected dogs often shaking their heads or scratching their ears. There may be an overproduction of earwax, which has a characteristic odor. In severe cases, the dog may become lethargic or show a loss of appetite.

Another typical sign is hyperpigmentationHyperpigmentation is a skin condition in which certain areas of the skin become darker than the surrounding skin. This can be caused by an overproduction of melanin, sun exposure, inflammatory conditions, or other factors. of the skin, which often appears in the areas affected by 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.. The skin may also appear thickened, a condition known as lichenification.

Diagnosis

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 a Malassezia 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. is usually made through a combination of clinical examination and specific tests. The veterinarian will carefully examine the affected skin areas and take a medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. to identify possible triggering factors. An examination of the earwax can also provide clues.

An important diagnostic test is cytologycytology is the study of cells, their structure, function, and chemistry. In medicine, it often refers to examining cells under a microscope for diagnosis of diseases., in which skin or ear swabs are examined under a microscope for the presence of yeast. The samples are applied to a slide, stained, and then evaluated microscopically. A high number of Malassezia yeasts in the samples confirms 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..

In some cases, a skin biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. may be necessary to rule out other dermatological conditions and make an accurate 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.. This procedure helps determine the extent of the inflammation and the type of skin changes.

Therapy

Treatment of Malassezia infections in dogs often requires a multifactorialMultifactorial refers to conditions or diseases that arise from the interplay of several causes or risk factors. In dogs and cats, these can be genetic predispositions, environmental influences, and nutritional factors that together lead to health problems. approach that addresses both the symptoms and the underlying causes. AntifungalAntifungal means effective against fungal infections. Antifungal medications are used to treat infections caused by fungi by inhibiting their growth or reproduction, or by killing them. therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. in the form of 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. or systemic medications is often necessary. 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. treatments include antifungalAntifungal means effective against fungal infections. Antifungal medications are used to treat infections caused by fungi by inhibiting their growth or reproduction, or by killing them. shampoos or creams containing ketoconazole, miconazole, or chlorhexidine. These help reduce the yeast populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment. on the skin.

In severe cases or when 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. treatment is not sufficient, systemic antifungals such as itraconazole or fluconazole may be prescribed. These medications work from the inside out to fight 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.. It is important to complete the entire prescribed treatment to prevent recurrence 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..

In addition, it is crucial to treat any underlying conditions that promote Malassezia proliferation. This may include treating allergies, controlling hormonal imbalances, or improving overall skin health. A change in diet or supplementationSupplementation is the addition of nutrients, vitamins, or other substances to a normal diet to compensate for deficiencies or to support general health and well-being. In dogs and cats, supplementation may vary depending on their health condition and nutritional needs. may also be recommended to strengthen the skin barrier.

Prognosis and follow-up care

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 dogs with Malassezia infections is generally good, provided the condition is diagnosed early and treated appropriately. Most dogs respond well to treatment and show significant improvement in symptoms within a few weeks.

However, it is important to note that 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. may be more common in dogs with 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. or recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. skin conditions. In such cases, a long-term management strategy may be required to prevent relapses and improve the dog’s quality of life.

Prevention

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of Malassezia infections in dogs focuses on maintaining healthy skin and controlling factors that promote the growth of the yeast. Regular grooming, including bathing with appropriate shampoos, can help keep the skin clean and free of excess lipids that could promote Malassezia growth.

Identifying and treating allergic or other predisposing conditions is also crucial. Regular veterinary check-ups can help detect and treat these conditions early before they become a problem.

A balanced diet rich in essential fatty acids can help strengthen the skin barrier and reduce inflammatory conditions. In some cases, the veterinarian may recommend special supplements to support skin health.

Finally, it is important to control the dog’s environment to avoid excessive moisture, especially in the ears and skin folds. Regular cleaning and drying of these areas can reduce 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..

Outlook on current research

Research on Malassezia pachydermatis, a yeast that often causes skin problems in dogs, has made significant progress in recent years. Scientists have been intensively studying the biology and pathogenicity of this microorganism to better understand how it spreads on the skin of dogs and what conditions lead to 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.. One focus of current research is the role of 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. and how it responds to the presence of Malassezia pachydermatis. This involves investigating why some dogs are particularly susceptible to infections, while others remain largely resistantResistant means being insensitive to a substance, drug, or treatment. In dogs and cats, resistance can refer to the ineffectiveness of antibiotics against certain bacterial strains or the insensitivity of parasites to certain pesticides..

Another area of research focuses on the genetic diversity of Malassezia species and their different pathogenicity mechanisms. Researchers have found that there are several strains of Malassezia pachydermatis that differ in their ability to cause disease. These findings are crucial for the development of targeted treatment strategies and vaccines.

Modern molecular techniques, such as genome sequencing, allow scientists to analyze the genetic makeup of Malassezia pachydermatis more precisely. These analyses can help identify specific genes associated with the virulence and survival of the fungus on the skin. Such information is crucial for developing new therapeutic approaches that specifically target these genes.

In clinical research, new antifungals have been tested to find more effective and safer treatment options for dogs with Malassezia infections. These studies evaluate not only the effectiveness of the drugs but also their tolerability and possible side effects. The goal is to develop treatments that not only relieve the symptoms but also combat the cause 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..

An emerging area of research is preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. research, which aims to prevent infections from occurring in the first place. This involves investigating which environmental factors or lifestyle changes can increase or decrease the risk of a Malassezia 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.. These studies could lead to new recommendations for dog owners in the future to minimize the occurrence of skin infections.

In summary, research on Malassezia pachydermatis in dogs is diverse and promising. The insights gained contribute to deepening the understanding of this common skin 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 developing new, more effective treatment and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies that improve the well-being of dogs.

Frequently asked questions (FAQs)

What is Malassezia pachydermatis? Malassezia pachydermatis is a yeast that commonly lives on the skin and in the ears of dogs. It is usually harmless but can cause an infection known as malasseziosis under certain conditions.

What symptoms does a Malassezia 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. cause in dogs? The most common symptoms include itching, redness, skin rashes, hair loss, and an unpleasant odor. Ear infections can also occur, especially in dogs with floppy ears.

How is a Malassezia 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. diagnosed? 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 usually made through a combination of clinical examination and microscopic analysis of skin or ear samples to detect the fungus. Sometimes cultures are also created to identify the fungus.

Which dogs are particularly susceptible to Malassezia infections? Dogs with skin folds, those prone to allergies, or those with weakened immune systems are more susceptible to Malassezia infections. Breeds such as Basset Hounds, Cocker Spaniels, and German Shepherds are more commonly affected.

How is a Malassezia 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. treated? Treatment usually includes antifungalAntifungal means effective against fungal infections. Antifungal medications are used to treat infections caused by fungi by inhibiting their growth or reproduction, or by killing them. shampoos, ointments, or oralOral means "through the mouth" and refers to the intake of food, medication, or other substances through the mouth. In veterinary medicine, many treatments are administered orally. medications. Special ear drops may be necessary for ear infections. Treatment depends on the severity 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. and should be monitored by a veterinarian.

Can Malassezia infections be transmitted to humans? Malassezia pachydermatis is generally not zoonotic, meaning it is not transmitted from dogs to humans. Nevertheless, hygiene precautions should be taken when caring for infected dogs.

Can a Malassezia 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. heal on its own? In some cases, mild infections may subside on their own, especially if the triggering factors are eliminated. However, veterinary treatment is often necessary to prevent relapses and ensure the dog’s well-being.

How can a Malassezia 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. be prevented? Regular grooming, including bathing with appropriate shampoos and controlling allergies, can help reduce the risk of infections. Caring for the ears and avoiding moisture in skin folds can also have a preventive effect.

What are the long-term consequences of an untreated Malassezia 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.? Untreated infections can lead to 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. skin problems, persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. itching, and discomfort. There is also the risk of secondary infections from 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. that enter through the damaged skin.

Is a special diet necessary for Malassezia infections? A special diet is not always necessary but can be helpful if 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. is associated with allergies or food intolerances. A balanced diet can strengthen the 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. and aid in recovery.