What is pyoderma in dogs?

Pyoderma is a bacterial skin infection — the most common dermatological condition in dogs. It is almost always caused by Staphylococcus pseudintermedius, a bacterium that normally lives on dog skin and becomes pathogenic when the skin barrier fails.

What are the symptoms of pyoderma?

Papules and pustules (pus-filled spots), yellow crusts, areas of hair loss surrounded by a ring of scales (epidermal collarettes), variable itching, and in deep pyoderma: nodules, ulcers and abscesses.

What causes pyoderma in dogs?

Almost always an underlying condition disrupts the skin barrier: allergies (most common), hypothyroidism, hyperadrenocorticism, seborrhoea, skin folds, parasites or immunosuppression. Without treating the root cause, pyoderma recurs.

How is pyoderma treated?

With antibiotics: cefalexin, amoxicillin-clavulanate or clindamycin for 3-4 weeks (superficial) or 6-8 weeks (deep). Always combined with topical therapy (chlorhexidine shampoo 2-4 %). Culture and sensitivity testing is key for recurrent cases to rule out MRSP.

Dog Pyoderma: Bacterial Skin Infection and Treatment

What Is Canine Pyoderma?

Pyoderma (from Greek "pyon" = pus, "derma" = skin) is a bacterial skin infection. It is the most common dermatological condition in dogs — an estimated 20-30 % of canine dermatology consultations involve pyoderma. The near-universal causative agent is Staphylococcus pseudintermedius, a commensal of dog skin that becomes pathogenic when the skin barrier is compromised.

Types

Superficial pyoderma (most common): affects the epidermis and hair follicle.
- Impetigo: subpilary pustules on the abdomen, typical in puppies.
- Superficial folliculitis: pustules at the hair base with epidermal collarettes (circular hair-loss patches with a ring of scales).
- Skin fold dermatitis (intertrigo): infection in nasal, lip, vulvar or axillary folds.
Deep pyoderma: affects dermis and subcutis. More severe.
- Furunculosis/cellulitis: nodules, suppurative ulcers, abscesses.

Symptoms

Papules and pustules (small spots filled with yellow pus).
Yellow or brown crusts.
Epidermal collarettes: circular patches of hair loss surrounded by a ring of scales — a hallmark sign of folliculitis.
Focal areas of alopecia.
Variable pruritus (mild to intense).
In deep pyoderma: nodules, ulcers, abscesses, local pain and fever.

Underlying Causes (essential to investigate)

Allergies (atopy, food allergy): the most common cause in adults.
Hypothyroidism, hyperadrenocorticism (Cushing's).
Seborrhoea (greasy skin).
Parasites: demodicosis, fleas.
Abundant skin folds (Bulldog, Shar Pei).
Immunosuppression (drug-induced or disease).

Treatment

Systemic antibiotics (always by prescription):

Superficial pyoderma: cefalexin 22-30 mg/kg/12h or amoxicillin-clavulanate, minimum 3-4 weeks.
Deep pyoderma: 6-8 weeks.
MRSP: antibiotic by sensitivity (doxycycline, clindamycin, rifampicin).

Topical treatment (fundamental and often underutilised):

Chlorhexidine shampoo 2-4 %: 2-3 times per week, leave on 5-10 minutes before rinsing.
Chlorhexidine gel or spray for localised areas.

⚠️ Without treating the underlying cause, pyoderma will recur within weeks. Allergy control (Apoquel, Cytopoint) or hypothyroidism treatment is as important as the antibiotic.