Ear infections are common in many dogs, particularly in breeds with ears that are not erect and/or breeds that have lots of hair on their ears. The most obvious symptom of an ear infection is a smell from the ears. Dogs with ear infections also tend to shake their heads frequently and scratch at their ears. The ears may also be red or have an excessive discharge. If your dog exhibits any of these symptoms, take him to the veterinarian as soon as possible. She will be able to prescribe a topical or oral medication to clear up the infection.