Jim, it sounds like your problem is indeed an allergy, a reaction to the chemical constitution of "true" nuts. (Peanuts are not nuts, biologically; they're legumes.) The problem that nuts, seeds, etc., present to those of us with diverticuli is mechanical ~ more a matter of physics than of chemistry. Any fragment that remains solid for the entire trip through the digestive/eliminative system, organic or inorganic, triggers the same reaction.

I used to be a fingernail biter, and chewer, and swallower. I suspect that ingesting all those nail parings in my younger years may have caused my current condition, and I'm absolutely sure that, if I were to eat a chuck of thumbnail today, I would experience the same reaction that would be caused by a pecan, peanut, tomato seed, etc.