Skin Diseases with Pus Drainage in Dogs

This table lists diseases in which the predominant sign is skin infection or pyoderma. Pyoderma is characterized by pus, infected sores, scabs, ulcers of the skin, papules, pustules, furuncles, boils, and skin abscesses. The skin infection is often secondary to some other skin disease, particularly an itchy skin disease that causes the dog to attack her own skin.

  • Actinomycosis and nocardiosis: Uncommon skin infections with abscesses and draining sinus tracts that discharge pus and respond slowly to treatment.
  • Acute moist dermatitis (hot spots): Rapidly advancing patches of inflamed skin from which the hair falls out. The skin is covered with a wet exudate of pus. Progresses through self-chewing and results in pyoderma. Often occurs under ear flaps of dogs with drop ears, such as Newfoundlands and Golden Retrievers. May be associated with an underlying skin disease, but can also occur in hot, humid weather if dogs swim or are bathed and don't dry thoroughly.
  • Cellulitis or abscess: Painful, warm, reddened skin or pockets of pus beneath the skin. Look for a cause, such as a foreign body, bite wound, or self-trauma from irritative skin disease.
  • Folliculitis (hair pore infection): Hair shaft protrudes through the center of a pustule. Superficial-Similar to impetigo, but extends to involve armpit folds and chest. Deep-Pustules become larger and firmer. Pus, crusts, and draining tracts in the skin.
  • Impetigo: Pustules and thin brown crust on hairless skin of abdomen and groin. Occurs in young puppies. May also be called puppy acne.
  • Interdigital cysts: A swelling between the toes that may open and drain pus.
  • Mycetoma: Painful swelling at the site of a puncture wound, usually on the legs or feet. Pus drains through sinus tracts deep in the mass. Usually caused by a fungus, but can be bacterial.
  • Puppy acne: Purplish red bumps on the chin and lower lip. Not painful. Also called impetigo.
  • Puppy strangles (juvenile pyoderma): Painful swelling of the face (lips, eyelids, ears), followed by rapid appearance of pustules and draining sores. Swollen lymph nodes around the head and neck. Occurs in puppies under 4 months of age.
  • Skin fold pyoderma (skin wrinkle infection): Red, inflamed skin with a foul odor in a lip fold, nose fold, vulvar fold, or tail fold.

This article is excerpted from “Dog Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.