Your pet’s skin, like your skin, is composed of different layers. Pyoderma is a bacterial infection of the skin. This infection has the possibility of penetrating through the first layer of skin (called the epidermis) and infecting the underlying layers. Superficial pyodermas are in the skin near its surface, and characterized by circular crusty lesions or red pimples. Deep pyodermas occur when bacteria invade beyond the hair follicle. Deep pyoderma is characterized by a pus build-up that can be expressed from the skin lesions. The main bacterial culprit that causes pyoderma is Staphylococcus pseudintermedius. This bacteria rarely infects normal healthy skin, but can easily infect injured or inflamed skin surfaces.


There are many contributing factors to the cause of pyoderma. If your pet has a weakened immune system their ability to fight off a bacterial invasion is significantly less than normal. A weakened immune response allows foreign bacteria to invade your pet’s skin and take over, when under normal circumstances, the body would fight off and prevent such an infection. Your pet can become more prone to bacterial skin infections while being treated with steroids, which decrease the body’s immune response to fight off bacterial invaders. Other causes of weakened immune response are hormone imbalance, caused by a thyroid disorder, allergies, and parasites. Your pet may also have trouble with producing skin that adequately shields internal systems from invaders. They may also be suffering from an underlying disease that affects the immune system like lupus. Fungal infections, such as ringworm (yes it is a fungus, not a worm!) open the skin up to bacterial infection because it causes open sores on the skin. Your pet may even have an allergic response to the normal bacteria on its skin. In worst-case scenarios, your pet may be suffering from pyoderma due to an underlying cancer diagnosis.

Whenever your pet is showing signs of a health issue your first step is to contact your primary care veterinarian. If it is indicated that your pet may suffer from pyoderma or another serious condition, a veterinary specialist is available at an ExpertVet certified hospital.

Diagnosis and Prognosis

The prognosis for most superficial pyodermas is good. The deep pyodermas are more difficult to cure and to get under control. Unfortunately it is not uncommon for pyoderma to return after all of its potential causes have been eliminated or treated. In these cases, immune stimulating drugs are used to fight the infection.

Determining the cause of your pet’s pyoderma requires laboratory tests. The test your veterinarian will order for your pet depends on how bad the infection is, how long your pet has experienced symptoms, and if your pet has previously had pyoderma. Some of the diagnostic tests that may be needed are:

  • Skin impression smear (bacterial infection, allergy, or immune system problem)
  • Skin scraping (parasites)
  • Skin testing (allergies)
  • Fungal culture (ringworm)
  • Skin biopsy (faulty hormones or immune system, bacterial, fungal or parasitic infections)
  • Culture (to determine the best antibiotic to treat the diagnosed bacterial infection)

If an underlying disease process is suspected, your Board-Certified Dermatologist will order additional diagnostic testing to find the underlying cause.


Because there are many causes for pyoderma, treatment of pyoderma also can be quite variable. Correction or control of the underlying cause is one of our goals. All pyoderma diagnoses will need to be on antibiotics for a MINIMUM of 21 days, although additional treatments may apply depending on the pyoderma’s underlying cause. Topical therapy by prescription shampoo is often prescribed.