ABSTRACT
An Austrian physician, Clemens von Pirquet, coined the term ‘allergy’ in to describe all of these forms of ‘altered reactivity’, ranging from what we think of now as allergic diseases (asthma, hay fever, hives) to various idiosyncratic responses individuals had after vaccinations, and, finally, the natural immunity following many infectious diseases.2 In the first decades of the twentieth century, the nascent allergy community used the terms ‘allergy’ and ‘reaction’ to describe any immune response to a substance to which an individual had previously been exposed, encompassing most of what we now think of as clinical immunology.
