Causes of dog yeast skin infection

As anyone who has showered in a public shower block will know, it is very easy to pick up ‘athletes foot’ or common fungal infections between the toes. This is because the skin is host to many bacteria and fungi.

Usually these organisms do not cause a problem and are kept under control by the immune system. HOWEVER, when conditions on the skin change or the immune system is compromised these bacteria and fungi cause infection and great pain.

These infections are known as opportunistic infections. If the number of yeast organisms on the skin increase, a yeast skin infection results. It is only the balance between a dogs good immune system and external factors that keep fungal infections at bay.

A common cause of a dog yeast skin infection is an increase in the amount of oils produced on the skin. This is most frequently associated with allergic skin disease. Another common cause of excess skin oils is seborrhea oleosa. Most seborrheic animals have secondary seborrhea, in which a primary underlying disease predisposes to excessive scaling, crusting, or oiliness, often accompanied by superficial pyoderma, Malassezia (yeast) infection, and alopecia (hair loss). The most common underlying causes are endocrinopathies and allergies. 

Some dogs will have a immune deficiency so that they ineffectively fight yeast infections, and this will result in chronic infection.

Ironically when a dog has severe ear swelling a vet will often prescribe cortisone to reduce that swelling. YET, dogs that receive immunosuppressive drugs such as corticosteroids (steroids) may also be unable to effectively prevent yeast infections, so may develop a chronic yeast infection. Thus completing the cycle.

Yeast dermatitis is not contagious; your dog did not get this infection from another dog.

Clinical notes:

Primary seborrhea is an inherited skin disorder characterized by faulty keratinisation or cornification of the epidermis, hair follicle epithelium, or claws. Hence a dog can get fungal infection in-between the pads or on the claws because of PRIMARY seborrhea or as a secondary infection because of a compromised immune system and contact allergies with grasses.

There are certain breeds thought to be genetically predisposed to developing yeast infections. They include:

• Australian terrier
• Basset hound
• Chihuahua
• Cocker spaniel
• Dachshund Silky terrier
• German Shepherd
• Golden Retriever
• Labrador
• Lhasa apso
• Maltese terrier
• Poodle
• Shetland sheepdog
• West Highland white terrier

Note these are inherited from the parent dogs. Thus if both German shepherd parents have a predisposition towards fungal infection, or in the case of a first generation labradoodle the poodle and the Labrador have a predisposition, there is a strong likelihood that the off-spring will have it too.