When a dog constantly licks and chews at his feet and body and has repeated ear infections, he's most likely suffering from an allergy. Allergies are an abnormal response by the immune system to a normally harmless substance. These seemingly harmless foreign substances such as food, pollens, molds, and dust mites can wreak havoc on a dog's life and are often responsible for repeated visits to the veterinarian's office. Fleas and common household items can be the culprits too.