[sageikosa]

She first noticed that she was feeling sick and started eliminating foods until we guessed it was the peanut butter sandwiches she was eating for lunch on tour. She did see an allergists who confirmed (with pretty obvious evidence) the reaction to peanuts.

She stopped eating peanuts for about a year, then gradually found she was capable of eating them again (her favorite candy was Reese's peanut butter cups, so a heartbreaking year that was). My belief is she is more cautious on the volume and frequency of her consumption now, but is otherwise unrestricted.

My guess was always that she must've had some low-grade infection (viral or otherwise) and the response was also broadly interacting with the proteins in peanuts.

The immune system isn't a designed system, it's a series of responses (and the ability to generate new response) that we broadly call a system because the net effect is as if there were some dynamic thing protecting us. Sometimes it just does its thing without regard to the segmentation faults it creates.