A classic example of a food allergy is
anaphylactic shock seen after ingestion of peanuts or after being stung by bees: as soon as the person or animal comes in contact with the allergen, their airway closes and they can't breathe.
According to her husband, he arrived home to find her sitting at the kitchen table with a plate of peanuts in front of her, and upon
seeing him she stuffed a handful into her mouth and then went into
anaphylactic shock.