Bacterial pyoderma is a common skin infection in dogs caused by bacteria. The term “pyoderma” translates to “pus in the skin,” and it occurs when the skin’s natural defenses are compromised. This allows bacteria that normally live on the skin, like Staphylococcus pseudintermedius, to multiply and cause an infection.
Symptoms of Bacterial Pyoderma
The symptoms of pyoderma vary depending on whether the infection is on the surface or deeper within the skin. Owners may first notice red, raised bumps (papules) or pus-filled lesions that resemble pimples (pustules). These are often accompanied by circular crusts, flaky skin, and hair loss. A distinct, musty odor may also be present, especially between the toes or within skin folds.
In short-haired breeds, the coat might look like it is sticking up, similar to hives, or appear “moth-eaten” from patchy hair loss. Surface-level infections, or “hot spots,” appear as moist, red, and irritated areas. Deeper infections are more severe, presenting with pain, crusting, and discharge of pus and blood, and the irritation often leads to scratching.
Common Underlying Causes
Bacterial pyoderma is almost always a secondary infection, triggered by a medical condition that weakens the skin’s barrier. Allergies are a frequent trigger, including environmental, flea, or food allergies. The resulting itching and scratching can break the skin, allowing bacteria to invade. In fact, atopic dermatitis is the underlying cause in 60% of recurrent pyoderma cases.
Parasites like Demodex or Sarcoptes mites can also lead to skin inflammation and secondary infections. Hormonal disorders are another cause. Conditions such as hypothyroidism (an underactive thyroid gland) and Cushing’s disease (overproduction of cortisol) alter the skin’s health and immune response, making it more susceptible to infection.
A dog’s anatomy can also be a predisposing factor. Breeds with prominent skin folds, like Bulldogs and Pugs, are prone to skin fold pyoderma. The warm, moist environment within facial folds, lip folds, and other areas creates an ideal breeding ground for bacteria.
Veterinary Diagnosis and Treatment
A veterinarian begins with a physical examination, noting the skin lesions. To confirm a bacterial infection, skin cytology is performed. This test involves taking a sample from the skin’s surface with tape or a microscope slide and examining it for bacteria and inflammatory cells.
If an infection is severe, recurrent, or unresponsive to treatment, a bacterial culture and sensitivity test may be performed. This test identifies the specific bacteria and determines which antibiotics will be most effective. Blood tests may also be recommended to check for underlying endocrine diseases like hypothyroidism or Cushing’s disease.
Treatment involves a course of oral antibiotics, often for several weeks. The specific antibiotic and duration depend on the infection’s severity and any culture results. Topical treatments like medicated shampoos, mousses, or sprays with ingredients such as chlorhexidine are also prescribed to help cleanse the skin and manage the infection.
Managing Recurrence and Contagion Risk
A common concern for pet owners is whether pyoderma can spread. Generally, the bacteria causing pyoderma in dogs are not contagious to humans or other healthy animals. The infection is an overgrowth of the dog’s normal skin bacteria. However, individuals with compromised immune systems should exercise caution.
Preventing recurrence requires managing the diagnosed underlying cause. For example, if allergies are the problem, consistent flea prevention, a special diet, or allergy medications are necessary. Regular grooming and bathing with medicated shampoos help maintain skin health. Keeping skin folds clean and dry is also important for predisposed breeds.