Dogs need to be monitored for a food allergy if you notice that your dog has allergy symptoms such as itching on various body parts, being lethargic or vomiting a lot. Your vet, through a series of exams can test for certain allergies a dog may have. Food Allergies are one of the more common allergies in dogs, and these can usually be attributed to the junk put into certain dog foods. Read more in this dog food allergy article.