If your dog has been scratching excessively or has developed a strange, musty smell, it could be a sign of Malassezia dermatitis. Malassezia in dogs is a skin condition caused by Malassezia pachydermatis, a type of yeast.

This yeast naturally lives in your dog’s skin and ears. In healthy dogs, this yeast coexists peacefully with other microorganisms on the skin, playing no significant role in their day-to-day life. However, when certain factors flare up, your dog will experience Malassezia.

The condition often affects areas where the skin is warm and moist, such as the ears, paws, armpits, and skin folds. Additionally, with specific physical characteristics, certain breeds are more prone to Malassezia infections.

Causes of Malassezia in Dogs

Malassezia yeast naturally exists on your dog’s skin without causing harm. However, certain conditions can disrupt this balance, allowing the yeast to multiply excessively. Here are the common causes of Malassezia in dogs:

Warm and Humid Environments

Malassezia loves to grow in warm and humid conditions. Dogs living in hot or humid climates are more susceptible to yeast overgrowth. Activities like swimming or bathing, when followed by improper drying, can also create ideal conditions for Malassezia to grow.

Allergies

Skin allergies are one of the most common underlying causes of Malassezia dermatitis. These conditions can be triggered by food, environmental allergens, or flea bites. Allergies can weaken the skin’s natural barrier, making it easier for yeast to take over.

Immune System Weakness

Dogs with weakened immune systems will be at a greater risk for Malassezia overgrowth. A compromised immune system may struggle to keep yeast populations in check, leading to recurring infections.

Antibiotics have the possibility to disrupt the balance of bacteria and yeast on the skin of your dog. While antibiotics target harmful bacteria, they may also eliminate beneficial bacteria that help keep the yeast population in check.

Poor Hygiene

Lack of proper grooming, particularly in dogs with long hair or skin folds, can trap dirt, moisture, and oil, creating a breeding ground for yeast. Neglecting regular baths or ear cleaning can also contribute to Malassezia overgrowth.

Common Dog Breeds Affected by Malassezia

While any dog can develop Malassezia dermatitis, certain breeds are at a higher risk because of their physical traits, skin structure, or predisposition to other health issues. Here are the common dog breeds affected by Malassezia:

Basset Hounds

Basset Hounds are known for their floppy ears and skin folds, which create a warm, moist environment where yeast can thrive. Their ears are particularly vulnerable, making regular cleaning essential to avoid infections.

West Highland White Terriers

Westies are often prone to skin allergies. Allergies can weaken the natural barrier of the skin and allow Malassezia to overgrow. These allergies make them frequent visitors to the vet for skin-related concerns.

Shih Tzus and American Cocker Spaniels

With long coats and floppy ears, these breeds are at higher risk of developing Malassezia dermatitis. The fur traps moisture, while their ears provide the ideal conditions for yeast to grow unchecked.

Boxers and Dachshunds

Boxers and Dachshunds are sensitive to environmental allergens. This vulnerability can lead to skin irritation and yeast overgrowth. Their sleek coats make symptoms like redness and hair loss more noticeable.

Poodles

Poodles’ long, hairy ears can hold moisture close to the skin, especially if grooming is neglected. This can encourage the growth of yeast and make them susceptible to Malassezia infections.

Bulldogs

Breeds like English Bulldogs and French Bulldogs have pronounced skin folds, which are a hotbed for moisture, warmth, and yeast growth. Regular cleaning and drying of these areas are critical for prevention.

Symptoms of Melassazia in Dogs

When Malassezia yeast overgrows, it disrupts your dog’s skin and causes noticeable signs that often worsen if untreated. The common symptoms of Melassazia in dogs are as follows:

Persistent Itching and Scratching

One of the first signs you may notice is your dog constantly scratching or biting at specific areas of their body, such as their paws, belly, or ears. This intense itchiness is caused by the yeast irritating the skin, triggering your dog’s need to relieve the discomfort. Over time, this scratching can lead to raw, red patches on the skin and open sores.

Bad Odor

If your dog starts to smell unusual, especially a musty scent, it could be a sign of Malassezia overgrowth. This odor often originates from specific areas like the ears, paws, or folds in the skin. Pay close attention to these areas.

Redness and Inflammation

As the yeast multiplies, it causes inflammation in the dog’s skin. This is what makes the skin look red, swollen, and sometimes shiny. If your dog has floppy ears, you might also see inflamed ear flaps or canals.

Scaly, Greasy, or Flaky Skin

Affected areas of skin may develop scaly, dandruff-like flakes. In some cases, the skin feels greasy to the touch due to excessive oil production. This combination of flakiness and oiliness is a classic symptom of Malassezia dermatitis.

Thickened or Darkened Skin

If Malassezia dermatitis goes untreated, the skin can undergo significant changes. You might notice that the affected areas become thickened, wrinkled, and leathery. Additionally, the skin may darken in color.

Hair Loss

The constant scratching, licking, and biting caused by the irritation can result in hair loss, particularly on the paws, belly, or ears. In some cases, you may also notice hair loss and bald patches surrounded by red or flaky skin. This is especially common in dogs with long-term or severe Malassezia infections.

Ear Infections

Malassezia yeast thrives in moist environments, making your dog’s ears a prime target. Signs of a yeast-related ear infection include red, swollen ear canals, a dark brown or black waxy discharge, and a strong odor. 

Your dog may shake their head frequently, paw at their ears, or tilt their head to one side in an attempt to relieve the discomfort.

Secondary Infections

In severe cases, Malassezia dermatitis can weaken the skin’s natural defenses, allowing bacteria to invade. Secondary bacterial infections often lead to additional symptoms, such as pus-filled sores, crusty scabs, or worsening redness and swelling. When these happen, your dog will experience more pain and discomfort.

Diagnosing Malassezia in Dogs

A correct and accurate diagnosis of Malassezia dermatitis is essential to make sure your dog receives the right treatment. Here are the methods we use at the clinic:

Physical Examination

The process will start with a physical examination of your dog. Our vets will inspect your dog’s skin, especially in commonly affected areas, including its ears, abdomen, and toes. We’ll look out for common symptoms such as redness, hair loss, thickened skin, or greasy patches. Based on this initial assessment, we’ll proceed with the next steps in the diagnostic process.

Microscopic Examination

By using a microscope, we can physically see Malassezia pachydermatis. Typically, we use two methods to obtain the sample: skin scrapings and acetate tape.

Skin Scrapings

A small scraping of the outer skin layer is taken to examine under a microscope. This method helps detect yeast cells as well as other issues like mites or bacteria.

Acetate Tape Preparations

A small piece of clear adhesive tape will be used to press against the skin to pick up yeast, which is then stained and examined microscopically. This is a quick and non-invasive way to detect yeast overgrowth.

Treatment for Malassezia in Dogs

Treating Malassezia dermatitis involves more than just addressing the yeast overgrowth. A comprehensive approach ensures the infection is resolved. Here are the treatment options we recommend for Malassezia in dogs:

Topical Medications

For small, localized patches of infection, antifungal creams, ointments, or sprays can be applied directly to the affected area. These are particularly useful for mild cases where small amounts of topical treatments can be used. To make sure your dog doesn’t lick the treatment for Malassezia, we recommend the use of an Elizabethan collar.

Oral Antifungals

Medications like fluconazole and terbinafine are commonly used to treat systemic yeast infections. These are typically used for much more concerning situations. While effective, these drugs can have side effects, some of which we will most certainly monitor. 

Medicated Shampoos

Shampoos containing antifungal agents like ketoconazole, chlorhexidine, or miconazole are highly effective in reducing yeast populations. Depending on your dog’s condition, we may recommend bathing your dog two to three times a week during the initial treatment phase. 

Preventing Malassezia in Dogs

Preventing Malassezia dermatitis is all about maintaining your dog’s overall health and reducing the factors that encourage yeast overgrowth. Routine grooming is essential to prevent moisture and dirt from accumulating on your dog’s skin, especially in areas prone to yeast growth, like skin folds, paws, and ears.

Additionally, making regular visits to the vet is important to monitor your dog’s health professionally. Vets can spot problems early before they turn into something more serious.

Conclusion

Malassezia dermatitis in dogs is a common but manageable condition. This disease can spiral out of control when left untreated. But with the right care, including targeted treatments and proper grooming, your dog can fully recover from this troubling disease.