I think it's important to remember that criticising dietary fads doesn't mean that such issues don't exist, just that in many cases things like gluten intolerance are simply self-diagnosed and – to be cynical – attention seeking. I'm bean intolerant and I don't get an aisle in the supermarket. If you'd smelled me after a chile con carne you'd beg them to give me my own aisle, one that's hermetically sealed and in a galaxy a long, long way away. But seriously, I have a genuine, unpleasant and painful reaction to beans in any quantity.
If you spend any time in the US, you'll know the danger of peanuts. Now there's a significant and growing allergy problem and certainly peanuts have a couple of potent allergens. But, firstly, most reactions to peanuts are minor. Very, very few people have significant reactions. Most US parents will tell you about someone they know whose kid died from peanuts (which is unlikely, given that the death rate from peanut-associated anaphylactic shock hovers around one per year in the US) thusly the peanut panic (which spreads to all nuts, and there's no relationship at all between almonds, peanuts, and walnuts). There is no safe-level of peanuts and anyone who even, for a moment, thinks of peanuts is like Mr Hitler's Rabid Dog. Remember the story about someone opening a bag on a plane and causing a child to perhaps, nearly, a little bit die? An immune system needs a good kick to get going, that's not one peanut molecule per plane (new SI measure of peanuttery to be approved).
But it's strangely fashionable to parade a child as fashionably peanut (or otherwise) allergic. There's an entire trade in home diagnosis so parents don't have to go through the trouble of consulting an actual allergist.
