How do I know if my dog has a bacterial or fungal infection

Fungal Infection (Aspergillosis) in Dogs

What Are Fungal Infections in Dogs?

Fungal infections in dogsspecifically those caused by the fungus Aspergillusare opportunistic organisms that are found everywhere in the environment, though they are more associated with compost piles, decaying soil, and standing water.

Fungal infections in dogs are painful, can be itchy, and are extremely frustrating. Many symptoms of fungal infections are vague and can often be mistaken for other conditions.

Though uncommon, fungal infections are considered a medical emergency. Unfortunately, by the time symptoms are noted for some dogs, the disease is already so advanced that humane euthanasia may be recommended.

Types of Fungal Infections in Dogs

Nasal aspergillosis is caused by fungi shedding spores called conidia. These spores can be inhaled and cause a localized infection that appears as thick, smelly pus coming from the nose.

Another type of this fungusif not cleared by the immune system through making mucus or sneezingcan infect the respiratory system, get into the bloodstream, and spread throughout the body affecting multiple organs. This is called disseminated aspergillosis.

Symptoms of Fungal Infections in Dogs

Dogs with the disseminated form of aspergillosis are often terminally ill and cant be cured. Dogs with the disseminated form often show symptoms related to which organs the fungus has attacked.

Dogs may have:

Dog with nasal aspergillosis can also have neurologic signs such as seizures, behavioral changes, and head pressing. However, they more often show the following:

Causes of Fungal Infections in Dogs

Dogs of any age, sex, or breed can become infected by Aspergillus.

However, young or middle-aged dolichocephalic (long-nosed) breeds such as Greyhounds, Collies, and Dachshunds are more often affected by nasal aspergillosis, as well as German Shepherds and Rottweilers.

Female German Shepherds from 2 to 8 years of age are most often diagnosed with disseminated aspergillosis.

How Veterinarians Diagnose Fungal Infections in Dogs

A physical exam of the nose and facelooking for signs of pain, symmetry, and air flow from both nostrilswill be a first step toward diagnosis of a fungal infection in dogs. Bloodwork and urine testing may then be recommended, as fungal organisms have been found in urine.

Imaging is often recommended, including:

• X-rays of the spine looking for evidence of bone destruction

• CT scans and skull X-rays to look for evidence of nasal and sinus bone destruction

• Rhinoscopy to directly visualize fungal growths in the sinus cavities

Biopsies, serology, fungal PCR, and fungal cultures of samples taken are more specialized tests, but they are often needed for a sure diagnosis.

Treatment of Fungal Infections in Dogs

Aspergillosis in dogs is slow to clear up. Antifungal medications often need to be given for months or years, and side effects of the drugs are common.

These medications include:

Supportive care such as pain medications, secondary antibiotics, and intravenous (IV) fluidsis often used while treating the underlying cause.

Recent studies have shown that dogs diagnosed with nasal aspergillosis saw an 80% success rate in curability with clotrimazole infusions and surgical removal of as much fungus and aspergilloma as possible.

However, nasal aspergillosis infection is often never 100% cleared, even with treatment.

Because dogs with disseminated aspergillosis are often very sick, many will either be humanely euthanized or die from the disease before medical treatment has a chance to work.

Recovery and Management of Fungal Infections in Dogs

The outlook for dogs with nasal aspergillosis is uncertain and depends on the severity and amount of bone destruction. Dogs with neurologic symptoms are most likely to have a brain infection.

Dogs with disseminated fungal infections have a poorer outlook, because they are often very sick at the time the veterinarian sees them. However, some studies have mentioned average survival times of greater than a year.

Dogs infected with nasal fungal infections often see their nasal discharge and symptoms clear up around two weeks after treatment. However, some persistent nasal discharge and sneezing may still happen because of the damage caused. Some dogs may need another procedure if the first doesnt fully work.

Follow-up CT scans and rhinoscopy are needed to see if full healing takes place.

Some infections may not be cleared up until years after therapy, so recurrence is possible. However, once cleared of infection, dogs are unlikely to become infected again.

Prevention of Fungal Infections in Dogs

Unfortunately, most fungal infections in dogs cannot be prevented, but as Aspergillus fungi often are more prevalent in decaying soils and compost, the best thing you can do is not allow your pup access to these areas.

Additionally, since Aspergillus is opportunistic in nature, dogs that are immunocompromised are at greatest risk. Take extra precautions when your dog is around other dogs, outside for a walk, pregnant, or receiving steroids or chemotherapy.

Fungal Infection (Aspergillosis) in Dogs FAQs

How do I know if my dog has a fungal or bacterial infection?

Given that symptoms are often similar, most of the time you won't be able to tell if your dog has a fungal or bacterial infection. Dogs can even have both types of infections at once. Diagnostic tests like cultures and cytologies are often needed to differentiate between the two.

WRITTEN BY

Michael Kearley, DVM

Veterinarian

Dr. Michael Kearley graduated from the University of Florida College of Veterinary Medicine in 2013. He graduated with a certificate in...

Skin Infections in Dogs: Bacterial Infections

Symptoms of Skin Infection in Dogs

Clinical signs associated with a skin infection in dogs can vary depending on the specific cause, but early manifestations of the skin condition can be similar regardless of the cause. Commonly seen symptoms are itchiness, hair loss, and generalized discomfort. Skin flaking and crusting can also be seen in some cases of skin infection.

Generalized redness, erythema, and skin inflammation can also be observed in dogs with skin infections. Untreated and severe cases will eventually emit a pungent or foul odor, and can even be fatal to highly susceptible and immunocompromised animals.

Types of Skin Infection in Dogs

Skin infection in dogs can be generally classified into 2 types: bacterial and fungal. Several bacterial and fungal species can invade and penetrate the skin barrier and cause infection in canines. Inflammation and breaks on the skin barrier can increase the risk of these microorganisms taking over, leading to an infection.

Its important to determine what type of skin infection an affected animal has because the treatment for both types is different. Medications that can control and eliminate bacterial organisms will have no effect against fungal infections, and likewise, anti-fungal medications are ineffective against bacterial skin infections.

Proper identification and diagnosis are important to have a specific and targeted treatment for your dogs skin infection.

Common Bacterial Skin Infection Causes in Dogs

Pyoderma is the most common bacterial skin infection in dogs. This bacterial skin infection is characterized by the presence of purulent (pus-like) discharge from the skin and is commonly caused by several species of bacteria.

Pyoderma in dogs is differentiated based on the tissues of the skin involved in the disease. Infections that only affect the topmost layers are called superficial pyoderma, and pyoderma that infiltrates and infects the deeper layers of the skin are called deep pyodermas. Superficial pyoderma accounts for the majority of pyoderma cases in dogs.

Most superficial pyoderma cases occur spontaneously and often present with a localized skin lesion. Loss of hair, or alopecia, is typically seen in superficial pyoderma cases, along with erythema (redness) and purulent discharge. Superficial pyoderma lesions tend to cause severe discomfort and will result in affected dogs trying to scratch or bite on the lesions, making the condition worse. The most common bacteria that causes this type of pyoderma is Staphylococcus pseudointermedius.

Deep pyodermas, on the other hand, usually have a triggering cause. Oftentimes, deep pyodermas result from untreated superficial pyodermas. Some cases of deep pyoderma are caused by the same bacterial species, but other organisms like E. coli, Proteus sp., and Pseudomonas sp. can also cause infection. Deep pyoderma cases affect the deeper portions of the hair follicle which results in erythema, hyperpigmentation, swelling, and skin ruptures. Affected areas of the skin are often painful and swollen.

Diagnosing & Treating Bacterial Skin Infections in Dogs

As mentioned, treatment for skin infections in dogs will ultimately depend on proper identification and diagnosis. The best way to diagnose skin infection in canines is through skin cytology, bacterial and/or fungal culture, and identification. Several methods like skin scraping, smear biopsy, and acetate cytology have proven effective in determining whether a skin infection is bacterial or fungal in nature. Identification of specific bacterial or fungal causes will involve culturing and isolating the bacteria taken from skin samples.

Most bacterial skin infections respond well to antibacterial medications. Localized and solitary bacterial infections can easily be treated with topical medications such as antibacterial creams and ointments. A more generalized infection will often need systemic antibacterial therapy for treatment.

Similarly, fungal infections are mostly treated with topical medications such as ointments or medicated shampoos, depending on how widespread the lesions are. Systemic antifungal medications are usually only prescribed in severe cases of fungal skin infections because of their potential liver and kidney side effects.

Read more:

Skin Infections in Dogs: Fungal & Yeast Infections

Common Skin Parasites in Dogs

My Dog Wont Stop Licking His Paws - Help!

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Yeast Infections in Dogs

What Are Yeast Infections in Dogs?

Does your dog frantically itch their skin? Have you noticed a bad smell or greasy fur when you pet them?

If so, they may have a yeast infection.

Yeast are fungal organisms that normally live on a dogs skin without causing problems. However, when a dogs immune system weakens or an underlying health condition, such as hypothyroidism, is present, yeast can overgrow and cause an infection.

The yeast that commonly causes skin infections in dogs is Malassezia, which grows on warm, moist areas of the skin. Yeast infections cause extreme itchiness and changes to the skin, such as thickening and discoloration over time.

Yeast infections in dogs are common among pups of all ages.

While yeast infections in dogs are not considered medical emergencies, they should be treated by a veterinarian immediately to prevent symptoms from worsening. If left untreated, yeast infections can cause extreme discomfort, which can lead to a decreased appetite and lethargy, necessitating prompt veterinary care.

Because yeast infections typically develop secondary to an underlying illness or suppressed immune system, they are not contagious among dogs or to pet parents.

Types of Yeast Infections in Dogs

Yeast infections can affect various areas of the skin, including the ears, skin folds, paws, armpits, vulva, and groin.

• EarsYeast infections of the earalso referred to as yeast otitiscause a thick, brown discharge and strong odor in the ear canal. Affected dogs repeatedly scratch their ears to try to relieve the discomfort. They may also shake their heads and develop a head tilt. Ear infections are commonly related to food allergies.

• SkinYeast dermatitis refers to a yeast infection anywhere on the skin. Affected dogs have a musty odor, greasy coat, flaky or thickened skin, and hair loss. They tend to lick the affected areas of the body, which leads to brown discoloration of the skin over time.

  • Dermatitis, which is often due to allergies or a suppressed immune system, can affecta dogs skin folds, armpits, vulva, and groin.

• PawsYeast infections that affect the paws are generally related to environmental allergies, such as allergies to grass or pollen. Dogs constantly chew or lick their itchy paws, which leads to brown discoloration between the paw pads. Over time, open sores can develop on the paws.

Symptoms of Yeast Infections in Dogs

Signs of yeast infections in dogs can vary depending on what area of the body is affected.

Symptoms of yeast otitis may include:

Symptoms of yeast dermatitis may include:

• Itchy skin

• Small, red bumps on the skin

• Brown discoloration of the skin

• Frequent licking or chewing of the affected area

• Greasy hair coat

• Thickened skin

• Strong odor

Symptoms of a yeast infection affecting the paws may include:

• Licking and chewing the paws

• Brown discoloration of the skin and fur

• Red, moist areas between the paw pads

Causes of Yeast Infections in Dogs

Yeast is opportunistic, which means that although it is naturally present on the skin, it can cause an infection when conditions are favorable.

Yeast infections in dogs can develop if a pup has a weak immune system or an underlying health condition. Underlying environmental or food allergies can predispose dogs to developing yeast infections.

Skin parasites, including fleas and mites, can cause dogs to repeatedly itch their skin, which disrupts the normal skin barrier, making an infection more likely.

Some breedssuch as Pit Bulls, Boxers, and Cocker Spanielsare more frequently affected by yeast infections.

How Veterinarians Diagnose Yeast Infections in Dogs

A vet may use several tests to diagnose a yeast infections in dogs.

First, they will gather a through medical history, including when the symptoms started, if your pet is taking any medications, and if they have previously been diagnosed with any health conditions.

Next, your veterinarian will perform a full physical exam to check your dogs overall health. They may also perform blood work to check for any abnormalities.

Additional tests will depend on what your veterinarian finds during the initial exam, but may include the following:

• Tape impressionDuring this test, your vet presses a piece of clear tape to the affected area of skin to collect a sample. Its then stained and examined under a microscope to identify yeast.

• CytologyA cotton swab is used to collect a sample from the affected area, and it is then rubbed gently onto a microscope slide. The sample is then stained and examined under a microscope to look for yeast.

• CultureA sterile cotton swab is used to collect a sample from the affected area. It is then sent to a lab to identify the type of organism present.

• Skin biopsyFor chronic infections or those that are unresponsive to treatment, a small sample of skin can be taken and sent to a lab for a more accurate diagnosis.

Treatment of Yeast Infections in Dogs

Treatment for yeast infections in dogs will depend on the location and severity of the infection. Yeast dermatitis is often treated with antifungal medications and prescription shampoos.

If the infection affects only one area, a topical medication may be all that is needed. For more widespread infections, oral medications and frequent bathing can help resolve the issue.

Yeast otitis is typically treated with topical antifungal medications and steroids to reduce inflammation. Your veterinarian may recommend that you use a medicated ear wash prior to instilling ear medications.

Paw yeast infections may benefit from medicated antifungal wipes and oral medications, including antifungals and steroids.

Recovery and Management of Yeast Infections in Dogs

Because yeast infections in dogs often develop secondary to another health condition, they will not resolve without veterinary treatment.

Determining the underlying cause of the yeast infection and treating it accordingly improves treatment success. For example, if your dog has an underlying food allergy, an accurate diagnosis and treatment can help their skin improve.

It can take a few weeks to a few months for a yeast infection to fully resolve, depending on the severity. Most dogs start to feel relief from their symptoms in a week or two, but it can take several additional weeks for a pet parent to notice significant improvement to their skin and coat.

Prevention of Yeast Infections in Dogs

Ensuring your dog receives regular preventive care and vaccinations keeps them healthy and less likely to develop infections.

Additionally, health conditions that can lead to yeast infections in dogs can be caught and managed early during routine wellness visits.

Yeast Infections in Dogs FAQs

What food causes yeast infections in dogs?

Most of the food ingredients that cause allergies in dogs are proteins. Chicken is the most common food allergen related to yeast infections.

What happens if dog yeast infections go untreated?

If a dogs yeast infection is left untreated, it will progressively worsen and lead to extreme discomfort. Over time, the discomfort can cause the dog to become very sick.

What should I feed my dog when they have a yeast infection?

Unless the yeast infection is due to an underlying food allergy, its generally fine to continue your dogs usual diet. However, it is best to follow your veterinarians recommendations when deciding what to feed your dog.

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WRITTEN BY

Brittany Kleszynski, DVM

Veterinarian

Dr. Brittany Kleszynski is a veterinarian and freelance medical writer who specializes in creating meaningful content that engages readers...