For many years now, I have assumed that I am allergic to crab, lobster, and shrimp. When I was little, my family would go out for crab legs and then we would go get ice cream (I would order chocolate). When we got home everything was fine until early in the morning, around 3am, when I would throw up. At the time we thought it was just the mixture of the shellfish and the ice cream. Then, when I was around 10, I went to a wedding where I ate some shrimp, and proceeded to throw up. That was when we decided that I was allergic to shellfish. However, the vomiting is the only symptom I have ever had and I am wondering if I really do have an allergy to shellfish or if something else is causing it, and if it is treatable.