Otitis (ear canal inflammation) is typically associated with an infection. These infections can be bacterial or yeast in origin. Depending on what type of infection it is, topical medication and cleaning usually provide a cure.
In some animals otitis can be a recurring condition. Recurring otitis can be indicative of a larger problem like allergies. Allergies are the most common reason for recurring otitis.
Increased moisture in the ears (after swimming or bathing), large/pendulous ear flaps (like in cocker spaniels), heavy wax build up, foreign bodies (grass awns), hair in the ear canal and allergies (food or environmental) all predispose dogs to infections.
Signs a pet may have an ear infection: scratching at the ears, shaking of the head, brown debris in the ear canals, malodorous ear canals
Treatment: most ear infections can be treated with simple ear cleaning and topical medication. For more complicated infections that don't resolve with this treatment an ear culture may be necessary to figure out what is causing the ear infection. For really severe, chronic otitis not controlled with medical management, surgery may be indicated.
It is very important to ensure that an ear infection has fully resolved with treatment. Your veterinarian can ensure an ear infection has resolved by completing an ear cytology (taking a sample from the ear and looking at it under a microscope). Untreated outer ear infections can lead to middle ear disease and cause a head tilt and vestibular signs (loss of balance).