External Ear Canal
The external ear canals in the dog and cat are shaped in the form of a capital letter L. Due to this cornucopia like or funnel shape canal, any sound made will be collected and amplified to some extent before it reaches the ear drum. The canals are lined with skin and thus have hairs and sebaceous glands present, but no sweat glands.
If the external ear canal should become irritated for any reason (e.g. mites, infection, allergy, etc.) the sebaceous glands will secrete a sticky fluid. As the long portion of the L shaped ear canal points up in both the dog and cat, any fluid or debris produced will likely remain in the canal and result in an excellent environment for opportunists, such as bacteria, to grow. Furthermore, if any water should collect in the canal this too will contribute to a potentially unhealthy situation.
The normal ear canal is clean in appearance at all times unless there is something wrong. As an owner you should be concerned if you notice any strong odor, any redness to the lining as well as increased sensitivity of the ear canals. Behaviorally, if you notice persistent shaking or rubbing of the ears you should investigate sooner rather than later. If you are unsure as to what to do, please let your veterinarian examine the ears to determine if any treatment is needed.
