Actually, the "spike" started in the early 80s. And the spike is backed up only by documented cases and not "oh I think I'm allergic cases." I agree that some allergies are "made up"; however, when the infamous "they" reports the numbers and the spike rates, it is based on tested cases.
Now, we can argue all day about statistics. I don't believe that the spike is as much as they say. I believe there actually were more peanut allergies back in the day, but I think our peanut product consumption was much lower than it it today, so the rates of exposure were much less.
For instance, I am 46 years old, went to elementary school in 60s. While we had peanut butter and jelly back then, it was not eaten everyday. We mainly had tuna, bologna, ham, etc. PB&J was almost a considered a treat at that time because it was sweet. My friends and I rarely had PB&J, althought that did pick up in the 70s. By the 70s, there was somewhat of a mini-explosion of peanut products entering the processed food market. It went big-time in candy and cereals. This entrance into the processed food market continued to expand well into the 80s and 90s. This is the time we saw the spike. So, were the allergic people always there and now their exposure levels were more dramatic or did the massive amounts of processed peanut snacks contribute? Who knows.
What I do know is that a peanut allergy and cross contamination issues are much harder to manage in this decade than they were in the 60s due to so many peanut-containing foods and, IMO, the high use of PB in lunches. It is a daily thing now versus a once-in-awhile treat. I'm not saying PB&J is bad and shouldn't be put in lunches--just that it is much more widely used than it was in the 60s when allergy rates were way down.