Pyoderma in Dogs: Signs, Causes, Treatment and How to Stop Relapses

Pyoderma in dogs is a bacterial skin infection, caused in most cases by Staphylococcus pseudintermedius, a bacterium that normally lives on canine skin and overgrows once the skin barrier is damaged. Superficial pyoderma shows up as small red bumps, pustules, crusts and rings of scale; deep pyoderma is painful, smells, and oozes blood and pus. Treatment belongs with your veterinarian: cytology first, prescribed antiseptic topicals as first-line care for surface and superficial cases, oral antibiotics reserved for deep or stubborn infections, and, above all, finding the condition that triggered it.

It is one of the most common reasons dogs are seen in small animal practice, according to the 2025 ISCAID guidelines. Pyoderma is almost always secondary to another skin problem, so if your dog has been itching for weeks, start with our guide to the best thing to give a dog to stop itching. This article focuses on the infection itself: what the lesions look like, why they come back, what your vet will do, and what is safe at home.

What is pyoderma in dogs?

The word means "pus in the skin." S. pseudintermedius is a normal resident of dog skin. When the barrier is compromised by scratching, allergic inflammation, flea bites, damp skin folds or long-term steroids, it multiplies in the epidermis and hair follicles. Our explainer on how dog skin works covers why that barrier matters.

So pyoderma is not something a dog "catches" at the dog park; it is an imbalance of the dog's own flora. The exception is methicillin-resistant strains (MRSP), which Loeffler and Lloyd (2018) flag for their zoonotic potential and the role of household hygiene.

What pyoderma looks like: a visual guide without photos

Photos can mislead, because pyoderma can look like ringworm, mange or yeast. Here is how the Merck Veterinary Manual describes each depth.

Surface pyoderma

The infection stays on the skin surface. This group includes acute moist dermatitis, the classic hot spot (a red, weeping, very painful patch that appears within hours), and skin fold dermatitis on the lips, face, vulva or tail. Dog hot spots have their own care plan, which we cover separately.

Superficial pyoderma

The most common form, involving the epidermis and the opening of hair follicles. Look for:

• small red bumps (papules) centered on a hair, sometimes topped by a white or yellow pustule;
• epidermal collarettes: rings of fine scale with a darker center, often mistaken for ringworm;
• yellowish crusts and flaking;
• a "moth-eaten" coat, especially in short-coated dogs, mostly on the belly and trunk.

If you are seeing isolated lumps instead, our guide to bumps on a dog's skin helps sort the possibilities.

Deep pyoderma

The infection breaks through the follicle into the dermis and sometimes deeper. Merck sums up its hallmarks as pain, crusting, odor, and blood and pus. Add swelling, ulcers, blood blisters and draining tracts. Typical sites are the bridge of the muzzle, chin, elbows, hocks, between the toes and the outer knees. Some breeds have their own literature, such as German Shepherd Dog pyoderma (Rosser, 2006); if you share your home with a German Shepherd, our article on German Shepherd skin allergies covers the itch side of the story.

Crusts can also come from yeast: see crusty dog skin and yeast, and our article on dog skin infection pictures for the limits of diagnosing from an image.

Surface vs. superficial vs. deep: side-by-side

Compiled from the Merck Veterinary Manual and the 2025 ISCAID guidelines (Loeffler et al.).

What causes pyoderma in dogs?

A University of Munich study (Seckerdieck and Mueller, 2018) reviewed 157 dogs with recurrent pyoderma. We converted their counts into percentages.

The authors note that in young dogs an allergy workup plus deep skin scrapings finds the cause in most cases, while in middle-aged or older dogs hormone testing and ruling out fleas should come first.

• Allergies: see our guides to dog dermatitis and to a dog constantly scratching and biting himself.
• Fleas: flea allergy dermatitis classically hits the lower back; our comparison of the best flea treatments for dogs helps you protect every pet in the house year-round.
• Demodex mites: often linked to deep pyoderma (see mange vs. allergies).
• Hormonal disease: consider hypothyroidism in a middle-aged dog that keeps relapsing.
• Local factors: skin folds, moisture, elbow pressure points, long-term steroids.

How vets diagnose pyoderma

The 2025 ISCAID guidelines are explicit: cytology should be performed in all cases before antimicrobials are used. Your vet presses a slide or tape onto a lesion and looks under the microscope for neutrophils containing cocci (round bacteria), or for yeast such as Malassezia. Other tests often follow:

• Deep skin scrapings to rule out demodicosis;
• Wood's lamp or fungal culture to rule out ringworm;
• Bacterial culture and susceptibility testing for deep, recurrent or non-responding pyoderma, or a dog that has already had antibiotics;
• Allergy workup, bloodwork and hormone tests depending on age and history.

Pyoderma treatment: what the guidelines say

Prescribed antiseptic topicals come first

For surface and superficial pyoderma, ISCAID names topical antimicrobial therapy alone as the treatment of choice. Merck lists chlorhexidine shampoos at 2 to 4% and benzoyl peroxide at 2.5 to 3%, used 2 to 3 times a week with 10 to 15 minutes of contact time. In a randomized trial (Borio et al., 2015), a 4% chlorhexidine shampoo-and-solution protocol for 4 weeks performed comparably to oral amoxicillin-clavulanate, including in dogs carrying resistant strains, though the groups were small (31 and 20 dogs). Your vet sets the product, frequency and duration. For bathing technique, see our anti-itch shampoo guide.

Oral antibiotics, only when needed

They are reserved for deep pyoderma and for superficial cases that do not respond to topicals. ISCAID recommends an initial course of 2 weeks for superficial and 3 weeks for deep pyoderma, always alongside topicals, followed by a recheck. Never stop early because the skin "looks better," and never use leftover or human antibiotics. In the US, following FDA Guidance for Industry #263, the last over-the-counter medically important antimicrobials for animals moved to prescription status in June 2023, so all of them now require a licensed veterinarian's authorization.

Antibiotic resistance and MRSP

In a teaching-hospital study (Hensel et al., 2016), 52 of 53 dogs with MRSP pyoderma (98%) had received at least one antibiotic beforehand, versus 42 of 45 (93%) with susceptible strains; the key difference was that the MRSP group had received more prescriptions and a wider variety of drug classes. Repeated courses are associated with that risk. After a course, our article on probiotics for dogs after antibiotics covers what is actually supported.

Home care for pyoderma: what is safe and what to avoid

No home remedy replaces your vet's plan, but some habits help and others make things worse.

For more, see home remedies for dog itching.

Recurrent pyoderma: a plan to stop the cycle

Loeffler and Lloyd (2018) stress that long-term success, and limiting resistance, depends on identifying and correcting underlying disease rather than repeating treatment. Merck lists the usual reasons for failure: cause not found, course too short, inappropriate steroids, no recheck. A realistic plan:

1. A recheck at the end of treatment, with repeat cytology.
2. Manage the cause: allergy control, year-round flea prevention, treatment of demodicosis or hormonal disease.
3. Proactive antiseptic topicals: ISCAID notes they may help prevent recurrences; your vet sets the schedule.
4. Skin barrier support: the 2015 ICADA atopic dermatitis guidelines list increasing essential fatty acid intake among long-term measures.

Further reading: the gut-skin axis in dogs, an active research area, and our complete dog itch relief guide, with realistic 2, 4 and 8-week milestones.

Where a supplement fits

A supplement is not a treatment for a bacterial infection. Its place is alongside your vet's plan and afterward, supporting the skin barrier and the allergic background that drives relapses.

Our #1 pick: Pure Majesty Pets Allergy Relief Chews

Our Allergy Relief & Itchy Skin Chews combine wild salmon, sardine, chia and borage oils (omega-3s and GLA), quercetin, bromelain, turmeric (95% curcumin), phytoceramides, biotin, colostrum, probiotics and prebiotics, zinc, vitamin E and rosehip in one daily soft chew. Cold-pressed oils, a Certificate of Analysis on every batch, made in North America. Price: $49.99, with free worldwide shipping.

Honest comparison: plain fish oil supplies omega-3s but none of the other barrier nutrients; for a food-allergic dog, a prescription diet comes first, with our chew as an add-on if your vet agrees. The product page suggests allowing 3 to 6 weeks of daily use before judging coat and scratching.

Runner-up: liquid collagen

For dogs that prefer a liquid on their food, our liquid collagen for dogs ($31.99) combines hydrolyzed type I and III collagen, undenatured type II collagen, salmon oil and hyaluronic acid as general nutritional support; see collagen for dogs with itchy skin. In the US, animal supplements are not FDA-approved drugs and cannot claim to treat disease, which is why we stick to "support."

Red flags: see your vet promptly

• Painful lesions that bleed, ooze pus or smell;
• Fever, lethargy or loss of appetite;
• Lesions spreading within days, or any lesions in a puppy;
• No clear improvement after a week of prescribed care, or relapse within a month of finishing treatment.

Frequently asked questions

Is pyoderma in dogs contagious?

Not in the usual sense, because it comes from the dog's own skin flora. Methicillin-resistant strains can spread between animals and, less often, to people, so wash your hands after handling lesions.

How long does pyoderma take to clear up?

Superficial pyoderma managed with consistent topicals usually improves over a few weeks. When oral antibiotics are needed, ISCAID recommends 2 weeks for superficial and 3 weeks for deep pyoderma before a recheck, and total treatment can be longer.

Why does my dog's pyoderma keep coming back?

Usually because the underlying cause is not controlled: allergies, fleas, demodicosis or hormonal disease. Short courses, skipped rechecks and resistant bacteria are the other common reasons.

Can I treat pyoderma at home without a vet?

No. Home care supports your vet's plan but does not replace it, and you should never give a dog human or leftover antibiotics.

Can stress cause pyoderma?

No study shows stress directly causes pyoderma. An anxious dog may lick or chew more, though, which damages the skin and makes infection easier.

Do supplements help with pyoderma?

A supplement is not a treatment for the infection. It can support the skin barrier and the allergic background alongside prescribed treatment, especially when relapses are the problem.

Sources

• Loeffler A et al. ISCAID antimicrobial use guidelines for canine pyoderma. Vet Dermatol, 2025. PubMed 40338805
• Seckerdieck F, Mueller RS. Recurrent pyoderma and its underlying primary diseases, 157 dogs. Vet Rec, 2018. PubMed 29419485
• Borio S et al. 4% chlorhexidine protocol in superficial pyoderma. Vet Dermatol, 2015. PubMed 26140535
• Hensel N et al. Prior antibacterial exposure in MRSP pyoderma. Vet Dermatol, 2016. PubMed 26909526
• Loeffler A, Lloyd DH. What has changed in canine pyoderma? Vet J, 2018. PubMed 29704943
• Olivry T et al. ICADA atopic dermatitis treatment guidelines, 2015. PubMed 26276051
• Khan SA, McLean MK, Slater MR. Concentrated tea tree oil toxicosis in dogs and cats: 443 cases. J Am Vet Med Assoc, 2014. PubMed 24344857
• Rosser EJ. German Shepherd Dog pyoderma, 2006. PubMed 16364785
• Merck Veterinary Manual. Pyoderma in Dogs and Cats. merckvetmanual.com

This article is for informational purposes only and does not replace the advice of your veterinarian. Any skin lesion that spreads, bleeds, oozes or keeps coming back should be examined by a veterinarian.