Dogs can develop internal or skin infections from contact with yeast or bacteria. While yeast infections are not contagious among dogs, certain types of bacterial infections are -- primarily those that affect the upper respiratory system. Depending on your dog's condition, keep him quarantined if you suspect he has a bacterial infection to prevent the spread of the disease to other dogs.
Dogs get infections of the skin from contact with malassezia yeast. This yeast causes dermatitis that can spread throughout a dog's system, due to malnutrition, hormonal imbalances, skin allergies or immune deficiency issues, according to the Mar Vista Animal Medical Center. Yeasts are small, spore-like forms of fungi that normally live on a dog's skin or in his digestive system, causing no issues. Once the surface of the skin becomes overly oily, irritated or moist, though, the yeast can proliferate and cause itchy, odorous lesions and unsightly thickening of the skin. Yeast infections can affect any region of a dog's skin and are common in the ears. The condition is not contagious; contact with an infected dog, direct or otherwise, will cause no harm to your dog.
There are many forms of bacterial infections that can affect your dog, the most common of which affect his skin and respiratory system. Respiratory infections caused by bacteria such as leptospirosis or bordetella bronchiseptica -- which causes kennel cough -- are highly contagious and potentially serious. These bacteria are airborne and can be passed from dog to dog by direct or indirect contact. Skin infections such as pyoderma can be contagious, depending on the cause of the infection; some cases have multiple types of bacteria in the skin lesions, according to PetPlace.com. A suppressed immune system can cause an infection by allowing bacteria such as the common staphylococcus intermedius to flourish, and will not affect a healthy dog. Other types of bacteria can cause an infection if passed to another dog with direct skin contact on irritated or broken skin.
When dealing with canine bacterial and yeast infections, always consult an experienced veterinarian for proper diagnosis and treatment of the condition. In some cases of yeast infections, secondary bacterial infections can arise, which can be contagious to other dogs. Avoid any contact with dogs that have bacterial respiratory or skin infections, as they can pass these infections to other dogs through direct skin contact, infected bodily fluids, contaminated surfaces and shared food. Have your dog vaccinated against the bacteria that cause kennel cough and leptospirosis to prevent the diseases in your dog, especially for dogs that live in warm climates, that are frequently outdoors or that you plan to board at a kennel facility or dog daycare.
Treatment and Considerations
After diagnosis through blood tests, a urinalysis, skin scrapings or a biopsy with a veterinarian, a vet may administer medication to your dog to treat the infection. A vet may prescribe antifungal oral medication such as ketoconazole, along with topical creams and shampoos to treat a yeast infection, according to PetPlace.com. Antibiotics including doxycycline and penicillin may be administered orally or intravenously to treat bacterial infections.
Topical antibacterial creams or shampoos can help relieve irritation and treat bacterial skin infections. Any underlying health conditions, such as cancer, skin allergies or parasitic infestation, must be treated to prevent the infections from persisting. Ask your veterinarian if your dog's infection is contagious or could develop a contagious secondary infection, and isolate affected dogs until the condition has been resolved.