Insulin Allergies do exist, but are rare. They were much more common when the insulin we used came from the bodies of pigs and cows. I have two online friends who have insulin allergies. One of them posted her problem on a diabetes website and some members there did not believe her. They called her a liar, because they had never heard of insulin allergies. She left the group and has never posted her problem again. I want to spread the word that these allergies do exist, and there are ways of dealing with the problem. See the article below presented by the Joslin Diabetes Center.