What Is Pyoderma in Dogs?

Medically Reviewed by Amy Flowers, DVM on December 11, 2021
4 min read

Pyoderma in dogs is, literally, pus in their skin. It's a bacterial infection of the skin and hair follicles. Pyoderma is the most frequent reason for antibiotic use in dogs. This condition is easily diagnosed since it is visible, but the treatment is challenging because of bacterial resistance.

Depending on the depth of skin involvement, pyoderma in dogs is classified into:

  • Surface pyoderma
  • Superficial pyoderma, also known as superficial bacterial folliculitis
  • Deep pyoderma

Pyoderma is a bacterial disease. The bacteria most commonly involved in causing pyoderma in dogs are:

  • Staphylococcus pseudintermedius, the most frequent cause
  • Coagulase-negative staphylococci
  • Streptococci
  • Micrococcus species
  • Acinetobacter

Some other bacteria like Proteus and Pseudomonas have been found in pyoderma in dogs. These bacteria probably don't cause disease on their own.

Your dog's skin is quite resistant to bacteria when it is dry. Moist areas of their skin allow bacteria to grow and cause an infection. 

Surface pyoderma involves the outermost layers of the skin, but not the hair follicles. This disease can appear in several different ways:

Fold pyoderma (intertrigo). If your dog has folds of skin that remain moist, bacteria can overgrow and cause disease. Look out for excessive itching, red and sore skin folds, a white or yellow discharge, and smelly skin.

Acute moist dermatitis (hot spots). Small red, moist patches appear on your dog's skin. These become painful, become larger and bald, and start oozing if not treated.

Bacterial overgrowth syndrome. Your dog has red areas on their skin, but no boils, visible pus, or crusts. You will notice itching, redness, baldness, and a bad smell.

This is the most common type of pyoderma in dogs and is also known as superficial bacterial folliculitis. It involves the outermost parts of your dog's hair follicles. Like other types of pyoderma, canine superficial pyoderma is a bacterial infection. The most common cause is Staphylococcus pseudintermedius.

Canine superficial pyoderma appears as red boils and pus-filled swellings on your dog's skin. You will notice that these are near or on the hair follicles. Your dog may develop areas of baldness and skin areas that are darker or lighter in color.

Superficial bacterial folliculitis in dogs often has underlying causes. The common ones are:

  • Allergies
  • Parasites
  • Poor grooming
  • Excessive scratching
  • Injuries
  • Hormonal disorders
  • Keratinization disorders (abnormalities of keratin, a structural protein of the skin)
  • Follicular dysplasias (defects of the hair follicles and hair shaft, making them prone to infection)

Deep pyoderma involves the deeper layers of the skin, called the dermis. Deep pyoderma will appear as pain at the infected site, crusting, a bad smell, and oozing of pus and blood. This is a dangerous condition because the infecting bacteria can enter the bloodstream, causing bacteremia (a dangerous infection of the blood). 

The bacteria involved are the same as the other forms of pyoderma. Since this type carries the risk of infection reaching the blood and other organs, it is always treated with antibiotics.

Antibiotics are the treatment for pyoderma, but the kinds prescribed will depend on the type of pyoderma your dog has.

If you notice pyoderma on your dog, you should visit your veterinarian. They will assess your dog and do any necessary tests. While the diagnosis is usually simple, your veterinarian may want to send a scraping of the skin or a swab of the pus to the laboratory for bacterial culture. This helps in choosing an appropriate antibiotic. 

Many antibiotics that were very effective earlier, like penicillin and ampicillin, are not used now. The most common cause of bacterial pyoderma in dogs, Staphylococcus pseudintermedius, is often resistant to these antibiotics.

Your veterinarian will probably prescribe a first-generation cephalosporin, clindamycin, or a combination of amoxicillin and clavulanate. These antibiotics have a higher success rate against pyoderma in dogs. Treatment is generally needed for several weeks.

If you notice your dog is not better after 2 weeks, or is developing new boils or other lesions, it is possible the treatment is not working. You should talk to your veterinarian. They may want to culture the pus from your dog's skin to guide further treatment.

Prolonged treatment is essential for a complete cure. If your dog has superficial pyoderma, your veterinarian will advise antibiotic therapy for 7 to 10 days after the infection disappears. For deep pyoderma, they will advise 14 to 20 days of antibiotic treatment after the pyoderma appears to be cured.

The superficial and surface types of pyoderma can be treated by local applications of chlorhexidine, benzoyl peroxide, or ethyl lactate. These drugs can be in the form of shampoos, sprays, gels, ointments, or creams. Such treatment is more rapidly effective, has lesser side effects, and reduces the duration of treatment needed. Treatment with medicated shampoo also removes crusts and cleanses your dog's coat.

If your dog has pyoderma over large areas of the skin, your veterinarian will probably decide to give antibiotics by mouth. Deep pyoderma and pyoderma that happens repeatedly also need prolonged courses of antibiotics.