Dogs have ears which have evolved to be self-cleaning. The skin grows outwards and carries debris towards the opening of the ear, like a conveyor belt.

The external ear canal is L-shaped with a vertical canal, then a horizontal canal, leading up to the ear drum (the membrane separating the delicate hearing and balance organs from the outside environment).

While the common yeast or fungal growth on a dog's skin is quite normal and causes no problems, it can proliferate and cause disease when there is a change is the dog's underlying health.

Ear mites, which can affect both cats and dogs, live in the ears but can venture out to the head and body, including the tail, or drop off the animal altogether and transfer from one pet to another.

Ear problems in dogs are not uncommon. Many normal dog ears will have some bacteria present, but a change in the underlying health of the ear can make this normal flora proliferate, cause disease and can allow other environmental bacteria to invade.