Skin Infections in Dogs: Bacterial Infections
Dermatological conditions are the most commonly reported problem in veterinary clinics and hospitals worldwide. They comprise around 20% to as high as 70% of all cases seen in an average veterinary facility. This is understandable since the skin is the largest organ in the dog’s body. It serves as the animal’s first line of defense against environmental hazards and different harmful organisms. In dogs, skin infections can occur either as a primary condition or secondary to an underlying health problem. Whichever the case is, proper identification and diagnosis are essential to effectively treat skin infection in dogs. Keep reading to learn more!
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.
It’s 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 dog’s 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.
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