I am not sure whether this allergy happened to be newly emerging at the time, as it is quite common for shellfish or other seafood allergies to develop in adulthood. The incidents that made me suspicious were due to small amounts of fermented shrimp paste. It was a strong suspicion before going into allergy testing but when the skin prick test came out negative I made the mistake of eating a few actual plump pieces of shrimp and suffered immensely for it.
Even after this I made a (turns out mistaken) assumption that since this is not an IgE mediated allergy, I might tolerate small amounts of it. If you can tolerate a tiny amount, or a small amount of fermented shrimp, a lot more options open up especially if you are into Asian foods. Alas, it was not to be.
Later incidents informed us that I react badly to even small amounts of fermented shrimp and undetectable levels (at least by eye and taste) of dried shrimp used to make broth.
Delayed tiny bumps all over skin
Skin prick test
Possible connection with dust mite allergy (positive) as a trypomycin cross reactivity issue
With a 75% chance to cross react, I have not taken the risk