Hello. Thank you for asking at HCM. I went through your history and would like to make following suggestions to you: 1. If your allergist has made diagnosis of anaphylaxis, it is highly desirable to carry Epipen as its prompt use can be life-saving should you have any episode of anaphylaxis. There is no specific test to diagnose anaphylaxis retrogradely, so diagnosis cn be assumed only after knowing the details of episodes. 2. I usually think of diagnosis when more than one systems are involved - any two of gastrointestinal, cardiovascular, respiratory and skin. So, if you have only vomiting and diarrhea (gastrointestinal) associated with crab, and no other symptoms like fainting, hypotension, collapse, palpitation, cough, respiratory difficulty, wheezing, swelings, itching, hives, etc, I would not first think of anaphylaxis. As your allergy tests are also negative, I would first think of non-allergic intolerance or something like food poisoning. However, if you have any of the above mentioned symptoms, anaphylaxis would be my first consideration, in that case, Epipen will be a need for you. Hope above information will help you. Thank you & Regards.