Dog Skin Infections: Bacterial vs Yeast (How to Tell the Difference) | PawPulse
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Dog Skin Infections: Bacterial vs Yeast (How to Tell the Difference)

📅 May 2026 ⏱ 2 min read 🩺 Vet-informed

🐾 Quick answer: Bacterial and yeast skin infections in dogs look and smell different. Learn how to tell them apart, what causes each, and why finding the underlying trigger is the key to preventing them from coming back.

Skin infections are extremely common in dogs and almost always secondary to something else — allergies, a wound, moisture, or hormonal imbalance. Understanding whether you’re dealing with a bacterial or yeast infection helps you have a much more useful conversation with your vet.

Bacterial Skin Infections (Pyoderma)

Bacterial skin infections — called pyoderma — are most often caused by Staphylococcus pseudintermedius. They typically look like:

  • Red, circular scabby lesions — often described as “target” lesions
  • Small pimples or pustules
  • Crusty patches
  • Hair loss in affected areas
  • Itching — mild to moderate

Bacterial infections are treated with antibiotics — topical for superficial infections, and oral antibiotics for deeper or widespread infections. Treatment typically lasts 3–6 weeks.

Yeast Skin Infections

Yeast infections are caused by Malassezia pachydermatis. The signs are quite distinctive:

  • Strong, musty, or “corn chip” smell — the most characteristic sign
  • Greasy, waxy skin
  • Reddish-brown staining — especially between toes, around the mouth, in skin folds
  • Darkening and thickening of skin over time
  • Intense itching

Yeast infections are treated with antifungal medication — shampoos, wipes, or mousse topically, and oral antifungal tablets for widespread infections.

How to Tell the Difference

The smell test is often your best clue at home — yeast infections have a distinctive musty, cheesy odour. Bacterial infections smell more like “infected” skin. But they often occur simultaneously, and only a vet with a skin swab can tell you definitively which you’re dealing with.

Treating the Underlying Cause

Allergies (environmental or food) are the most common underlying cause by far. Hormonal disorders like hypothyroidism and Cushing’s disease also predispose dogs to skin infections.

🚨 When to See a Vet
  • Any suspected skin infection — don’t guess and treat at home
  • Infection spreading rapidly or dog seems in pain
  • Deep skin lesions or draining tracts
  • Recurrent infections — underlying cause needs investigation
  • No improvement after 7–10 days of treatment

Skin infections are uncomfortable for your dog but very manageable with the right treatment. Getting the diagnosis right from the start — and addressing the underlying cause — prevents the cycle of recurrence.

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Researched using current veterinary guidelines. Always consult your vet for medical advice about your pet.