Pyoderma is one of the most common skin problems vets see in dogs, and superficial pyoderma is the most frequent reason antibiotics are used in small animal practice. Since you will likely see this condition many times throughout your veterinary career, it pays to know the current approach well. If you are a dog owner looking at red bumps, scabs or bald patches on your dog, here is the short version: pyoderma is a sign of another problem, your vet will want to confirm it before treating, and treatment often starts with medicated products on the skin rather than antibiotic tablets.
What is Pyoderma in Dogs?
"Pyoderma" literally means "pus in the skin", and in dogs it refers to a bacterial skin infection. The main culprit is Staphylococcus pseudintermedius, a staph species that lives on the skin and mucous membranes of healthy dogs. It is isolated from over 90% of superficial pyoderma cases and around 60% of deep cases.
That detail changes how you think about the disease. Pyoderma is not usually caused by new bacteria getting into a wound. It develops when something else changes the skin and the dog's own resident bacteria overgrow and invade. Pyoderma is always secondary to an underlying cause. Trauma (scrapes, cuts, friction, chronic pressure), parasites and atopic skin disease are the most common triggers, and anything that makes the normally dry skin surface moister makes overgrowth easier.
Itching keeps the problem going: the damaged skin itches, the dog licks or scratches, and the skin gets more damaged. Yeast (Malassezia) is a common co-infection that needs different treatment, which is one reason your vet checks a skin sample.
Types of Pyoderma
Vets classify pyoderma by how deep in the skin the infection goes, because depth changes how serious it is and how it is treated.
- Surface pyoderma stays on the outermost layer of skin. Examples include hot spots (acute moist dermatitis), skin-fold infection (intertrigo) and bacterial overgrowth.
- Superficial pyoderma involves the outer part of the hair follicles and is the most common form. It is also called superficial bacterial folliculitis. Impetigo, often called "puppy pyoderma", belongs in this group.
- Deep pyoderma reaches the deeper layers of the skin (the dermis and below), as in furunculosis, where infected hair follicles rupture into the surrounding tissue. It often affects the chin, the bridge of the muzzle, the feet and pressure points like elbows and hocks, and it can develop in lick granulomas.
Deep pyoderma is the serious one. It is painful, the bacteria can spread into the bloodstream, and it needs prompt veterinary care.
Symptoms of Pyoderma in Dogs
Though pyoderma can follow several kinds of skin problems, it usually presents in similar ways. Common signs include:
- Itchy skin (how itchy varies from dog to dog)
- Redness and skin irritation
- Small raised bumps (papules) and pustules, often centered on hair follicles
- Epidermal collarettes: round, scaly rings left behind as pustules break and heal
- Crusts and scales
- Oozing of the skin or dried discharge
- Patchy hair loss
- Odor from the skin
Deep pyoderma looks worse: pain, swelling, crusting, odor, and discharge of blood and pus, sometimes from draining tracts.
The trunk and the belly are the most commonly affected areas. Skin folds (including lip folds), armpits, the spaces between the toes and pressure points are also at higher risk.
Causes of Pyoderma in Dogs
Finding the underlying problem is the key to getting rid of pyoderma for good. Common causes include:
- Allergies: atopic dermatitis, food allergy and flea allergy
- Parasites such as fleas and mites (demodectic and sarcoptic mange); deep pyoderma is commonly linked to demodicosis
- Skin folds
- Skin trauma such as cuts, scrapes, friction or pressure
- Ringworm (dermatophytosis), a fungal infection that can trigger pyoderma and also mimics it
- An underactive thyroid (hypothyroidism)
- Hormonal disease such as Cushing's disease (hyperadrenocorticism) and sex hormone imbalances
- Seborrhea and other keratinization disorders
- Immune-mediated skin disease and follicular dysplasias
- Poor grooming
Diagnosis
Diagnosis starts with a physical exam and a discussion of the dog's medical history. Pyoderma often looks typical, but appearance alone is not enough. Current international guidelines recommend cytology in every suspected case: a quick in-clinic microscope check of a sample from the skin. Cytology confirms that bacteria are causing the problem and tells a bacterial infection apart from yeast or a sterile (non-infectious) disease. That matters because antibiotics do nothing for a yeast infection.
Your vet will also rule out conditions that look like pyoderma, including demodicosis, ringworm, Malassezia dermatitis and pemphigus foliaceus. Depending on the history and findings, that can mean coat brushings, hair plucks, skin scrapings for mites, fungal tests, and blood work to look for hormonal disease. If pyoderma keeps coming back, the search for the underlying cause needs to be repeated or widened, and your vet may suggest a referral to a veterinary dermatologist.
A culture and susceptibility test (a lab test that grows the bacteria and shows which antibiotics work against them) is recommended whenever antibiotic tablets or injections are being considered. It is strongly recommended if the dog has had antibiotics recently or often, or has had a resistant staph infection before. For deep pyoderma, the antibiotic choice should always be based on culture results.
Treatment
Treatment has two jobs: clear the infection and deal with whatever caused it.
Topical therapy comes first. For surface and superficial pyoderma, antiseptic products applied to the skin (medicated shampoos, sprays, mousses or wipes) are the treatment of choice and are often the only treatment needed. This holds even for infections caused by resistant staph. Your veterinarian chooses the product and tells you how to use it.
Systemic antibiotics are for specific situations. Antibiotics given by mouth or injection are always needed for deep pyoderma. For surface and superficial cases, they are kept for dogs that don't respond to topical therapy alone or when topical treatment isn't practical. Your veterinarian decides whether an antibiotic is needed, which one, and for how long, ideally guided by a culture.
The recheck matters. Your vet will want to see the dog again before the first course of treatment ends to decide whether to stop or continue. Give every medication exactly as prescribed, and don't stop early because the skin looks better or keep going on your own. There is no evidence that continuing antibiotics after the signs have resolved helps.
Treat the cause. If the allergy, parasites or hormonal disease behind the pyoderma is not controlled, the infection will keep returning.
Resistant Staph and Why Stewardship Matters
Some staph strains are resistant to many antibiotics. Methicillin-resistant S. pseudintermedius (MRSP) and, less often, methicillin-resistant S. aureus (MRSA) cause pyoderma that looks exactly like any other case. Only a culture can tell them apart. The outlook for these infections is still considered good, and topical therapy remains first-line for surface and superficial cases.
The risk of MRSP passing from dogs to people is considered low; it may be higher with MRSA. Owners of dogs with resistant infections should know about that potential, and thorough hand-washing after handling the dog is a sensible habit. And because skin is easy to reach with topical treatment, pyoderma gives vets a real chance to use fewer antibiotics, which helps slow resistance.
Why Pyoderma Comes Back
Recurrent pyoderma usually has a predictable explanation. The Merck Veterinary Manual lists the common reasons treatment fails: the underlying trigger was never found, the infection was undertreated, steroids or other immune-suppressing drugs were used inappropriately, the wrong antibiotic was chosen or it wasn't given correctly, or the dog was never rechecked.
Prevention
Preventing pyoderma means preventing or controlling the skin problems that set it up:
- Keep your dog on the ongoing parasite prevention your veterinarian recommends, including flea and tick control.
- Work with your vet to manage skin allergies. In allergic dogs, controlling the allergy is a better strategy than treating infection after infection with antibiotics.
- Have new itchy, red or scabby spots checked early, before a small problem spreads.
- Your vet may suggest a cone (e-collar) to stop licking and scratching while the skin heals.
- For dogs with recurrent pyoderma, your vet may recommend ongoing antiseptic topical therapy, which may help prevent relapses.
Summary
Pyoderma is a common bacterial skin infection in dogs, caused by the dog's own staph taking advantage of skin changed by another problem. It usually responds well to treatment, but it tends to return if that underlying cause isn't found and controlled. See your veterinarian promptly if your dog has painful, swollen or draining skin, as these can be signs of deep pyoderma. For a related read, see our article on the Increase in Flea Allergy Dermatitis in Dogs and Cats.
Originally written by Amber LaRock. Updated by the I Love Veterinary editorial team.
Sources
- Merck Veterinary Manual: Pyoderma in Dogs and Cats
- Veterinary Dermatology: Antimicrobial use guidelines for canine pyoderma by the International Society for Companion Animal Infectious Diseases (ISCAID), 2025
- Veterinary Dermatology: Synopsis of the ISCAID antimicrobial use guidelines for canine pyoderma, 2025
- Veterinary Dermatology: Recommendations for approaches to meticillin-resistant staphylococcal infections of small animals, WAVD Clinical Consensus Guidelines, 2017
This article is for general information and is not a substitute for advice from your veterinarian.
