Hmc thankyou for those.
A lot of foods that are allergenic can become denatured when cooked. So for example, in egg allergies some people can't eat a fried egg or scrambled egg but are fine eating egg baked in cakes and breads. It's something to do with a high heat source for a length of time is enough to change the stucrure of the protein so it no longer causes a problem. Not all allergens behave this way. Nuts is one, celery is another, that no matter how much you cook them, the allergen is still present and problematic. Same with strawberries. My dd can't eat them raw but can in say, jam. However she is one of the ones who is allergic to baked as well as raw eggs, so there's no hard or fast rule about how people will respond.
I have my own theories about allergies and it's to do with how foods are manufactured these days. There are so many products with may contain warnings, tht we also have to avoid, that it makes me wonder if the traces of these allergens are sometimes in foods and sometimes not. We were told that if we introduce dd to a new food, say white fish, that if she dis okay with it we need to continue feeding it to her regularly. If we gave it once and then. It again for a while, she has the potential as someone who suffers from allergies, to react to it the next time. So of there are traces of nuts say in a choc bar and you eat it, and then you don't encounter that trace again for a while, it may be that you might also react with the next encounter.
This isn't scientific. Just my experiebpnce with my Dd and the realisation that there are so many foods now with nut warnings than ever before.
Also, someone upthread said there are studies being done where small amounts of allergens are introduced and gradually the person builds up an immunity. Apparently, it's as simple as that, according to people like the person upthread or even members of my dP's family.
It's not as simple as that and what they've found is that if they get to the stage where someone can ingest peanuts they have to eat something like 5 a day everyday. They also found that if someone didn't eat that for something like 6 weeks the allergy would sometimes come back and be as severe as it was before.
Also, in some cases where the allergy appears to be cured, people start developing different issues, like allergies to other things or to exercise. There are cases of people suffering anaphylactic shock from exercising.
It's not as simple as just a little bit each day and you'll be sured.
So much is unknown about allergies, but the very real fact is that for some people a simple mistake can be fatal. The only thing allergic people can do to stay truly safe is to avoid the allergen/s.