Otitis externa is the medical term for an inflammation of the external ear canal. The ear canal in dogs in cats is L shaped, meaning there is a vertical ear canal and a horizontal ear canal. This unique anatomy inhibits the airflow into the ear canal and makes it hard for dirt and debris to be flushed out. This also holds moisture in the ear canal which can cause problems. In severe cases the eardrum may rupture and cause a missile ear and/or inner ear infection as well. In the worst case this can cause permanent facial nerve paralysis, head tilting , or loss of balance. Otitis externa can occur in any animal, and can there are many different causes. The most common are, breeds of dogs with large droopy ears, underlying immune disorders such as allergies or hypothyroidism, moisture from bathes or swimming and excessive oil and ear wax secretion. Dogs with excessive hair growth in the ear canal are also prone to otitis externa.
 

The three main infectious agents involved in otits externa are, bacteria, ear mites and yeast. Otits externa is usually noticed when your pet starts shaking his head violently and pawing or scratching at his ears. Dogs may even yelp when their ears are petted and some dogs will have a reflex leg thump when there ears are manipulated. Other clinical signs are yellow discharge or dark brown waxy build up, red inflamed ear pinna and a foul or yeasty odor coming from the ear. Diagnosis is usually fairly straight forward and can be done right at the veterinary clinic. An otoscopic exam can be done to rule out a mass or foreign body. And a simple smear and examination with a microscope can differentiate between yeast, bacteria or mites, sometimes it is necessary to obtain a bacterial culture to see what antibiotic of choice is appropriate in cases that are refractory to treatment. In chronic ear infections blood tests may be necessary to rule out underlying medical conditions such as allergies or hypothyroidism for cause of the otits externa. In straight forward cases, flushing with a cleansing antiseptic agent and application of the appropriate topical medication may be all that is necessary to clear the infection. In dogs with excessive hair growth in the ear canal the veterinarian may choose to pluck the hair to allow the ear canal to dry and to aid in the application of the medication. Sometimes oral antibiotics or antifungals will be prescribes in more serious cases and in cases that are secondary to another medical condition the primary condition will be treated concurrently while treating the otitis externa. In general most common cases of otits can be prevented or limited in severity by instituting a few simple management techniques. Use a cleaning/drying agent after swimming or bathing your pet. Have your groomer or vet pluck excess hair from the ear canal. Routinely clean your dogs ear with an appropriate ear cleaning solution and visually check you dogs ear for any unusual buildup. A lot of that "doggy" odor that you smell when interacting with your dog comes from the ears so keeping your dogs ears clean and fresh will benefit their health and make your time spent with your dog more pleasant.