Your pet’s ear is shaped like the letter L. The portion you can see from the outside (vertical canal) is only half of the ear canal. The vertical canal angles into the horizontal canal, which ends at the ear drum (tympanic membrane). Otitis externa refers to inflammation of the external ear canal caused by: ear mites, allergies, foreign bodies, and infections to name a few. Pets with otitis externa may shake their head, show pain when pet near their ear, head shaking/rubbing, redness within ear canal, and odor. Some dogs with otitis externa show no symptoms and the infection is found incidentally on examination by the groomer or veterinarian. Physical examination is necessary to examine the ear canal and determine the extent of the inflammation. Your veterinarian will obtain a sample of the discharge from the ear to evaluate for the presence of bacteria, yeast, and mites. Most cases of otitis externa are treated with an ear cleaner, to remove inflammatory debris, and a topical medication to resolve the infection. Recheck examinations are important to ensure that the infection has completely resolved. Unresolved infections may break through the ear drum and progress to a middle ear infection.