 [ Symptoms ] what should i do if exercise is painful [ Disease ] this is an interesting question and i am glad you asked it in order to develop an allergy to a substance you have to be exposed to it in other words it is extremely rare to experience an allergic reaction to something on first exposure it is not impossible but it is fairly rare  one good example is penicillin millions of people took penicillin as children and suffered no ill effects many of those people today have penicillin allergies that early exposure caused their bodies to mount an extreme immune reaction to penicillin later on that could be what happened to you too if a physician confirmed your allergy you need to take it to heart allergies not only can come on later in life they can get worse over time so that diarrhea from eating eggs today could turn into anaphylaxis eventually you also should be aware that people with a documented egg allergy may be discouraged from getting flu shots i would suggest you talk with your health care provider to see if this restriction applies to you sorry you are going through this it is difficult to give up a well loved food