Bacteria And Yeast Infections in Dogs

Low numbers of bacteria and yeast usually live harmlessly on the surface of healthy dog skin; so, it’s common and quite normal to find small (occasional) numbers under the microscope. Overpopulation causes clinical signs and requires treatment.

What Are Common Microbes Found On Dog Skin?

Bacteria and yeast (Malassezia) are single-celled microbes, invisible to the naked eye. There are two main forms (shapes) of bacteria commonly detected from a skin swab cytology: cocci (sphere-shaped) and bacilli (rod-shaped). Yeast are dark spheres (larger than bacteria) often with an extra smaller sphere, so they take on the shape of small “footprints”. Low numbers of bacteria and yeast usually live harmlessly (symbiosis) on the surface of healthy skin; so, it’s common and quite normal to find small (occasional) numbers under the microscope. This is especially true for yeast and cocci, while less so for bacilli. If no bacteria or yeast are detected (none seen), that’s normal too. Even though we share some types of skin bacteria and yeast between pets and people, they aren’t contagious. This is because there’s almost always an underlying reason(s) the bacteria or yeast overpopulate (1+, 2+, 3+, 4+) to cause clinical signs.

What Are Signs Of Skin Infections In Dogs?

Clinical signs of bacterial and/or yeast ear infection (one or more):

Repeated scratching at ears, head, or neck
Frequent head shaking
Greasy coat
Frequent licking or chewing at paws
Chewing at other parts of body
Licking or scooting hind-end
Dark discharge
Yellow discharge
Hot spot (red or moist)
Scabs
Pimple / pustule
Wart or lump
Strong odor
Hair thinning or loss

How Do I Check For A Skin Infection?

Veterinarians suspicious of a skin infection will swab the skin surface, within skin folds, or between toes for cytology. At MySimplePetLab, skin swab samples send in from our Skin & itch Dog Test from home are thinly smeared (“rolled” or “dotted”) onto a glass microscope slide, colorized with special stains, and examined with 1000x (oil-immersion) magnification. This is the gold-standard way to search for bacteria and yeast on the surface of the skin. The distinction between yeast, cocci, and bacilli is important for treatment selection. Yeast are fungi, so need to be treated with anti-fungal medication. While both cocci and bacilli are forms of bacteria, each type is generally susceptible to different classes of antibiotics. The MySimplePetLab skin cytology results will also indicate if the cocci or bacilli bacteria found are extracellular (outside cells) or intracellular (inside cells). Finding the bacteria free-living on the skin surface is most common. If bacteria are being gobbled up by immune cells (intracellular bacteria), it’s a sign that the infection is even more serious.

When And How Are Skin Infections In Dogs Treated?

If the bacterial and/or yeast counts are high (1+, 2+, 3+, 4+) in your dog’s skin swab samples, and especially if with one or more clinical signs, then a physical exam of your dog’s skin is needed by a veterinarian. Treatment of microbe infections on the skin typically involves prescription anti-fungals for yeast and prescription antibiotics for bacteria. Either can come as ointments or sprays topically applied to the surface of the skin or given by mouth, and/or antiseptic wipes, cleansers, or shampoos that inhibit yeast or bacterial growth.

How Do I Know If The Infection Is Gone After Treatment?

Retesting with a skin cytology (Skin & Itch Dog Test) after treatment and a recheck skin exam, even if symptoms have improved, is commonly done by veterinarians to ensure that the yeast and bacteria numbers have returned to normal (none seen or occasional). Especially when skin treatments aren’t working, it’s important to take the next step with your veterinarian. They may recommend a culture of the discharge to determine exactly which bacteria is the problem and which antibiotic(s) are able to kill it.

How Does My Dog Get A Skin Infection?

When your dog develops a skin infection it is also important to look for underlying causes like parasites (fleas; ear or skin mites), allergies (from environment, food, or contact), endocrine diseases (hypothyroid, Cushing’s), immune suppression, medication reaction, skin barrier or gland disorders, or growths/tumors that allow the yeast and bacteria to overgrow. Solving or supporting the underlying problem may be necessarily to fully resolve or best manage the ear infection.

Additional Questions? Chat us at MySimplePetLab.com, email [email protected], or call us at 833-PET-TEST (833-738-8378).