an infestation in the ear, caused by either bacteria or by virus

Unfortunately, any dog that lives in a warm humid climate is susceptible to an ear infection. If your Great Dane likes to frolic and sometimes swim, he may be a candidate. Ear infections are usually caused by parasites, bacteria, yeast, allergies or trauma. If you notice that your Great Dane has been scratching his ears excessively or shaking his head, you should have his ears checked.

presence and growth of bacteria or viruses in the ear.

a blockage of the auditory tube in the middle ear that causes bacteria to build up and resulting in an infection. Usually treated with antibiotics.

Chronic ear infections typically have an underlying cause (usually allergy). It is important to address this problem in addition to the infection itself to minimize on-going ear inflammation.