I'm not a physician nor do I play one on TV. However, look at Epigenetics as an explanation for the rise in peanut allergies and other ailments.
This is interesting.
At around age 60 or so, I suddenly could no longer wear anything washed in laundry products that had perfume or optical whiteners or dyes. I would break out in a very uncomfortable rash everywhere from the clothing washed in these products.
I have long had some seasonal pollen and mold allergies and I had some tiny areas of psoriasis that would become worse under stress and then disappear for years. The respiratory problems are controlled by antihistamines and the skin problems with a single small appplication of cortisone cream. Both resolved the laundry product reaction, as well.So, perhaps I was already in a sensitive state.
All it took was switching to one of the laundry products with no additives and I am fine.
Peanut and soy were not as prevalent in the past. I do see how constant exposure can sensitize people. Perhaps those with severe allergies used to simply die young. I do know non-allergic folks who cannot abide the smell of peanuts or peanut butter and will become nauseated if exposed to them. Maybe this is a milder reaction and there is a spectrum of sensitivity. I also know folks who find dark greens and celery to be bitter-tasting and they avoid them. One such person gets canker sores if they eat these vegetables.