My allergy to peanuts and cashews has been going strong for over 50 years and I'm still alive. Peanuts and cashews are the worst, and to me, the difference is like between a bee (peanut) and yellow-jacket (cashew) sting. Similar reaction, but stronger and nastier. Peas, lima beans and lentils also cause an allergic sensation, but won't get me sick
As a kid, today you get protected, but once out on your own, shit happens. In third grade, I knew I couldn't eat the peanut butter candy we were making in class, but wanted to help, so I stirred it. That got me sent home with my eyes swollen shut. Later in life, I've been hit by a "maple frosted" donut, learned about mole sauce and sate sauce the hard way (note to self; watch out if the E on the end of the sauce's name is pronounced as A). Those cut up garlic pieces in the dipping sauce at the Thai restaurant were actually chopped peanuts. Those rice crispy squares only had 1 tablespoon of peanut butter in the batch, but it got me. The chicken salad sandwich with cashews did too. I could probably die from a large dose, but sense it pretty quickly. What gets my goat is the warnings on packaged goods saying the product was made in a factory that uses peanuts. I ignore those labels and only sensed peanuts in M&M plains and a Hershey White Chocolate candy bar.
For me, the smallest bit ingested means I'm going to puke. It might take 10 minutes or three hours, but it is going to happen. Normally, once I know it is in my system (seconds after swallowing), I'll drink a bunch of water and try to puke it out of my system. That sort of works. I also get wheezy and my throat closes a bit, but not as bad as others report. Then, I get sleepy. Even the dust in the airplane gets my eyes itchy. Years ago, I tried the desensitization approach on my own, but didn't like the reaction and stopped pretty quick.