I'm afraid that I have no suggestions for finding out what is wrong, or getting rid of whatever it is. But I do have a little story illustrating how long allergy producing things can hang around. My parents had guests over, and one of them went into a full blown allergic response to something, and had to go outside. He was absolutely stunned that this had happened as his only known allergy was to horses, and it seemed unlikely that there had been horses in my parents' living room. Except ... my mother loved Victorian furniture, and had a set of horsehair upholstered chairs and a couch. Original upholstery; the horsehair had not been attached to a horse for probably 100 years!
