Dogs typically contract ear mites through contact with other infected animals. Ear mites are also common in outdoor cats, who in turn may pass them on to dogs in the household. Ear mites are miniscule parasites that feed on the oil and wax in a dog's internal or external ear canal.
The symptoms dogs generally experience when infected with ear mites include excessive scratching and rubbing of the ears, head shaking, strong odor from the ears and inflammation of the ear canal. Other symptoms include black or brown waxy secretions from the ears and a coffee-ground-like discharge that obstructs the ear canal.
If left untreated, ear mites can cause a number of complications, such as skin infections and the rupture of blood vessels in the ears. Owners should clean dogs' ears routinely once a month to prevent ear mite infections, and then clean the bedding of dogs that have just gotten over an infection to prevent reinfestation. At home, ear mite infections can be treated by gently cleaning the ears with a canine ear cleaner to remove debris. A veterinarian may also prescribe an anti-inflammatory drug or an antibiotic to clear up the infection. These are typically applied directly inside the ear or on the skin.