Atopic and nonatopic IgE-mediated allergy: a new interpretation of old facts?

Coined 80 years ago, the term 'atopy' to designate a group of diseases associated with IgE and a hereditary background has raised many discussions. In particular, it is difficult to consider as part of an atopic syndrome cases of IgE-mediated allergies to isolated allergens without evidence of a familial inheritance. The postulate expressed in this essay is that in humans we are essentially dealing with an atopic IgE-mediated allergy, which is the equivalent of a genetically determined high IgE response, and with a nonatopic IgE-mediated allergy, which is the equivalent of a low IgE response in mammals and rodents.