Pyoderma literally means “pus in the skin” and can be caused by infection, inflammation, or cancer. It is not common in cats. Bacterial pyoderma is usually caused by an overgrowth of bacteria that normally or temporarily live on the skin. The infection is usually triggered by an underlying condition, such as allergies, flea or mite infestation, and chin acne. However, any disease that causes itching and self-trauma can trigger a pyoderma. Warm, moist areas of the skin (such as areas around the mouth, genitals, and toes) have an increased risk of infection.
The most common sign of bacterial pyoderma is excessive scaling, particularly on the back near the tail. Scales are often pierced by hairs. Intact pustules ("pimples") are almost never found. Small, solid bumps on the skin (called miliary dermatitis) is common. Hair loss, open sores (ulcers), bloody crusts, and draining wounds are usually seen when the pyoderma is deep within the skin. Recurrent, nonhealing deep pyoderma in cats can be associated with multisystem disease, such as infection with feline immunodeficiency virus or feline leukemia virus, or atypical mycobacteria.
Diagnosis is based on signs. Microscopic evaluation of samples taken from the skin may also help. It is also important to identify and treat any underlying causes. Multiple deep skin scrapings are needed to exclude parasitic infections. Bacterial and fungal cultures may also be done.
The most common causes of a bacterial pyoderma that recurs after treatment include failure to identify an underlying trigger or stopping antibiotics too soon. Thus, it is important to fully follow your veterinarian’s instructions for any medication. Cats often have concurrent bacterial and yeast infections of the skin, and it is not uncommon for your veterinarian to treat both diseases.
Antibiotic treatment is usually prescribed for at least 3 weeks. Longterm, recurrent, or deep pyodermas typically require 8 to 12 weeks or longer to heal completely.
Attention to grooming is also crucial. The hair coat should be clipped in cats with deep pyoderma, and a professional grooming is recommended in medium- to longhaired cats. This will remove excessive hair that can trap debris and bacteria and will help grooming. Carefully follow your veterinarian’s instructions regarding grooming.
Also see professional content regarding pyoderma.