I'm allergic to fish (can't eat tuna, salmon, etc.) but I can eat food made with pretty much any type of bonito-based dashi I've ever tried.
Especially Japanese food like nabe, nikujaga, Aomori-style thick niboshi soup base ramen.
Never really understood it.
Antibodies don't have to bind only to proteins, it could be some lipid, carbohydrate, any molecule big enough. Most of the time it's some protein, but it's not an allergy proteins in general.
I absolutely cannot take that smell.
It’s pretty common in Sweden and not too expensive. I bought from ICA last time I tried it.
Plenty of places ship internationally AFAICT
https://swedishgoods.co.uk/shop/ <- this one for instance
One could (but maybe shouldn’t) eat a bonito flake or two as an experiment.
Do you react to other fish products such as south east Asian fish sauce? Salted and/or fermented fish?
I'd guess that your allergy is to some class of proteins in the fish - and that the production steps for dried bonito (and maybe the time required) denature or destroy those proteins.
She can have bonito and fish sauce, and (most strangely) canned tuna. Any fresh fish makes her violently ill. She had to learn the hard way that many restaurants make their tuna salad with fresh tuna.