Nut allergies

My son is allergic to walnuts and pecans; he is sensitive to other "tree" nuts, as well as peanuts. I am sure others have said this or have written about this phenomenon, but I would really like to know where this came from. When I was growing up in the '70s, I didn't know a single person who had a nut allergy, now I know several kids with nut allergies. How could something go from basically unheard of to common?

Nut allergies wouldn't be a problem if they weren't so dangerous. In my Long Island congregation, we lost a 15 year old girl because she accidentally ate some candy.

Unfortunately, our allergist has no firm answers as to the cause, and the "treatment" is to avoid all nuts, plus carry antihistamine and an epi-pen in case our son eats a nut and has a reaction. There is no explanation for this besides vague theories, and all "sensitivity" levels, except the very lowest, can be deadly.

What gives here?

Just wondering, like the medical professionals do, I think. I hope there are some answers soon.