Pyoderma in Cats (Bacterial Skin Infection, Pus in the Skin)
Overview of Bacterial Skin Infection in Cats
Pyoderma is a bacterial infection of the skin. Pyoderma can be divided into surface pyodermas (infection on the skin surface), superficial pyoderma (infection within the skin) or deep pyoderma (infection under the skin).
The health impact from pyoderma can range from mild with superficial pyoderma to severe with deep pyoderma. Superficial and surface pyodermas can cause intense itching leading to discomfort. The underlying cause of the pyoderma may also have a negative health impact on the cat, depending on the disease.
Pyoderma can be caused by underlying allergies to food, fleas or other things in the environment, and/or immune-medicated diseases.
The most common bacteria causing pyoderma is Stapylococcus pseudointermedius.
Deep bacterial infections are more common in outdoor cats. Cats are predisposed to pyoderma in warm humid environments.
What to Watch For with Pyoderma
Any of these should trigger a visit to your veterinarian: Red, itchy and painful skin lesions Pustules (pimples) Draining sores Hair loss
Diagnosis of Feline Pyoderma
Diagnostic tests may include: A detailed medical history. Expect to be asked about how long the lesions have been present, what they looked like initially, and whether itching preceded the lesions or appeared after the lesions. A complete exam of all body systems with particular attention paid to the type and location of lesions present in the skin. Cytology. A pustule may be opened and the contents examined under a microscope. With a pyoderma, bacteria and neutrophils (a type of white blood cell) are usually seen. Neutrophils without bacteria may suggest another disease. Culture. Deep pyodermas are typically cultured to identify the exact bacteria that are present and to help select the best medication. Superficial pyoderma lesions are rarely cultured since they almost always grow the same bacteria (Staphylococcus intermedius). Other tests, such as skin scrapes, allergy tests, complete blood count or blood chemistry analysis, to determine the underlying cause of the pyoderma, especially if the pyoderma recurs after treatment.
Treatment for Feline Pyoderma
Treatment may include: Antibiotics to help kill the bacteria infection. The most commonly used antibiotics include cepahlexin, Clavulanic acid-amoxicillin (Clavamox), Clindamycin, and Cefovecin injectable (Convenia). Antibacterial shampoos and creams containing benzoyl peroxide, ethyl alcohol or chlorhexidine. Treatment to prevent underlying itchy skin diseases or diseases that suppress the immune system for long-term success.
Home Care and Prevention for Pyoderma
Give all medications as instructed. Even if lesions clear up early, antibiotics should be given until all medications are finished. Observe your cat for draining lesions.
Some causes of pyoderma are not preventable, but the presence of fleas can worsen pyoderma. The best prevention is to follow a complete flea control program as recommended by your veterinarian. In addition, keep your cat clean and brushed free of mats.
In-depth Information on Feline Bacterial Skin Infections
Surface Pyoderma A hot spot (pyotraumatic dermatitis) is a surface pyoderma that is caused by self-trauma due to some itchy problem, often an allergy. It has the appearance of a moist, red lesion with acute loss of hair and is intensely itchy. Skin fold pyoderma occurs in folds of skin that are moist and difficult for the animal to keep clean. Examples are: facial fold, tail fold, vulvar fold and lip fold pyoderma.
Superficial Pyoderma Superficial pyoderma is infection within the skin. The bacterium that is nearly always incriminated in this infection is Staphylococcus intermedius. This form of pyoderma is the most common kind and affected animals have pustules that may rupture leaving a ring of scale that is called an epidermal collarette.
Pustules may or may not be associated with hair follicles. Pyoderma associated with hair follicles causes hair loss (alopecia) as the pustules rupture. Superficial pyoderma rarely is a primary disease, but rather is a symptom of another skin problem. These underlying skin problems can be pruritic (itchy) or be caused by a suppressed immune system. Pruritus (itching) leads to self-trauma that causes damage to the skin and breakdown of natural defense mechanisms allowing bacteria to penetrate into the epidermis causing pyoderma. Examples are allergy and infestation of parasite like mites or lice. A suppressed immune system may allow bacteria to establish an infection within the skin. Examples are: hormonal diseases, like Cushing’s disease or hypothyroidism, some infectious diseases, cancer or any disease that suppresses the immune system. Excessive use of corticosteroids like prednisolone can suppress the immune system. There are some cases of pyoderma that recur after treatment, yet an underlying cause can never be found. This is called idiopathic pyoderma or primary pyoderma. Superficial pyoderma must be differentiated from other diseases that present with pustules such as autoimmune skin diseases and certain fungal skin diseases.