Dogs ear infections (Otitis Externa) are often caused by foreign material in the ear canal or by bacteria that enter the canal and become established there. These infections are seen more often in floppy-eared dogs than those with erect ears.
When wax builds up in the external ear canal, secondary infections may begin. Itch and irritation become unbearable, and the dog scratches violently causing serum to ooze into the canal and feeding the infecting bacteria. The ear canal must be thoroughly cleaned, and medication is applied into the canal. This usually means a trip to the vet.
Whether your dog rarely leaves his big fenced yard or goes on frequent walks, he is likely to encounter cheat grass or wild oats. The awns or seedpods of those plants are attached to little beards that stick in your socks when you walk through the grass. Those same bearded awns can make their way into a dogs ear canal, causing great discomfort and necessitating a trip to the vet for removal.
If your dog is longhaired, his foot hair will pick up these grass awns. These nuisances must be removed promptly or the sharply pointed seeds may penetrate the skin and begin to migrate into the tissue, requiring minor surgery to remove them.
Another condition seen quite often in floppy-eared dogs is ear hematoma. This condition appears like a fat ear, and usually follows an ear infection. Regardless of the specific cause, the infected ear irritates the dog and causes him to shake his head violently. When he whips the ear, vessels are torn and a pocket of blood forms between layers of cartilage and skin.
This is another condition that will require a vet to treat. First, the initial problem must be solved, then the pocket of blood serum is drained, usually by surgical means. The ear is immobilized for a time, and healing is usually uncomplicated.