Pyoderma is a skin infection that can cause itching, redness, crusts, pustules, a rash, and/or hair loss at the site of the infection, among other, grosser symptoms. Dogs and cats both can get the condition, which occurs when something has happened to the skin that allows bacteria to grow unchecked. Pyoderma can be treated with oral or topical antibiotics and/or shampoos, but the underlying cause has to be addressed, too.


Pyoderma is a bacteria infection of the skin. It happens when the skin’s natural defenses break down, thereby allowing common skin bacteria to multiply. Opportunistic bacteria that don’t normally live on the skin can also colonize when the skin’s defenses have been broken down. Other organisms, such as yeast and fungal organisms, can also take advantage of the skin changes that occur with pyoderma and establish their own infections.

All pyodermas have an inciting cause. In general, any disruption in the immune system’s ability to keep bacteria from overgrowing on the skin can lead to pyoderma, including:

  • Damage to the skin (bite wounds, bug bites, scratching, ringworm, mange, burns, chemical irritation, urine scalding, tumors)
  • Allergies to fleas, foods, or other allergens
  • Autoimmune disease
  • Immunosuppression caused by certain medications, viral disease, cancer, liver disease, thyroid disease, or other illness
Dogs and cats of any age can be affected by pyoderma.

Symptoms and Identification

The clinical signs of pyoderma may include:

  • Rash
  • Redness
  • Itching
  • Crusts
  • Scales
  • Pus-filled blisters (called pustules)
  • Hair loss
  • Oozing sores
  • Foul odor
Diagnostic testing to confirm a bacterial infection and determine the primary cause may include several of the following:

  • Adhesive tape prep: Placing a small strip of adhesive tape against the pet’s skin or hair for a few seconds permits skin cells and other debris to stick to the tape. When your veterinarian examines the tape under a microscope, bacteria, yeast, inflammatory cells, cancer cells, skin parasites, and other abnormalities can often be seen.
  • Skin scrape: Gently scraping the surface of the skin with a dull scalpel blade or similar instrument can remove cells just below the skin’s surface. These cells are then examined under a microscope. Mites that cause mange can be identified using this technique.
  • Bacterial culture: A swab of the skin (or of a pustule) can be sent to the lab to determine what bacteria are present and which antibiotics should be used to treat the infection.
  • Fungal culture: Hairs from infected skin can be sent to the lab to be tested for ringworm or other fungal infections.
  • Biopsy: After a local anesthetic or sedation is administered to the patient, a small piece of skin can be removed and sent to the lab for evaluation.
  • Blood testing: A blood sample can reveal internal disorders that may have affected the skin’s barriers to infection. More extensive testing may be pursued to look for thyroid disease or other specific disorders that can cause or contribute to skin diseases.
  • Allergy testing: Along with food trials (for food allergy), blood and/or skin testing can help determine if an allergy exists, identify which allergens are causing a problem, and help your veterinarian determine whether specific treatment for the allergy is possible.

Affected Breeds

Dogs and cats of any breed can suffer with pyoderma.


The infection itself can usually be taken care of with a course of antibiotics prescribed by your veterinarian. Antibiotics can be administered by mouth, by injection, or applied topically in a variety of formulations (gels, foams, creams, shampoos, leave-in conditioners, and sprays). However, the underlying cause –– whether it’s parasites, hormonal imbalances, allergies or sanitary issues –– must be specifically addressed to prevent the problem and keep it from recurring. When a pet’s primary disease or husbandry problem is under control, chances are good that the animal will recover from pyoderma and not suffer a recurrence.


The best way to prevent pyoderma is to address any underlying diseases, follow good basic hygiene techniques, and employ appropriate animal husbandry practices.

This article has been reviewed by a Veterinarian.