However, the short answer is deeply unsatisfactory to me because the word allergy was originally coined for a truly revolutionary concept that got lost, and the word perverted to mean something else entirely. Yet, it is a remarkable concept that, if revitalized, could make us see immune responses in a different, perhaps more holistic, light. Indeed, it might even make us question the current definition of the “immune system” itself.
To elucidate the original concepts behind the words “allergy” and “atopy“, and to contextualize their usage today, let’s delve into a brief history of these two words.
In 1906, a young Viennese pediatrician,coined the word “allergie“. His ambition was no less lofty than to define the essential features of an immune response. Accordingly, he defined allergy or rather allergie as an “acquired, specific, altered capacity to react“. According to Igea ( ), Von Pirquet‘s revolutionary insight was in conceptualizing the function of the immune system not as one that rids the body of disease but as one whose contact with an antigen changes the reactivity of an individual.
Von Pirquet‘s revolutionary concept was deeply misunderstood in his own time, and instead “became perverted and limited” to describe “hypersensitivity” reactions (). Over the past century, “allergy” was further misappropriated out of the clinic and absorbed into the immunology lexicon to instead convey “antipathy and rejection” ( ).
Sadly, today, allergy has become an “umbrella” term used to describe all manner of adverse immune responses including drug side effects, and adverse reactions to food and food additives ().
In 1916, Cooke and Vander Veer () distinguished patients with multiple “natural” hypersensitivities from those sensitized “artificially” by injection. Many of the former had hay fever (allergic rhinitis), asthma and eczema (atopic dermatitis), and some suggestion of common family history of similar disorders. The familial history implied a genetic underpinning for these diseases.
In 1923, at the suggestion of Edward D. Perry of Columbia University, Arthur F. Coca and Robert F. Cooke () further distinguished hay fever and asthma patients by coining the word, “atopy“, which they defined as “inherited human hypersensitiveness“. Thus, “atopy” was originally coined to describe this specific subset of “allergic” reactions.
In the 1970s, Jack Pepys () and others showed association between atopic disorders and high levels of circulating allergen-specific IgE, and pushed for its current usage. Thus, today, “atopy” is used to describe the so-called “classic triad” of hay fever (allergic rhinitis), asthma and eczema (atopic dermatitis), assumed to have a genetic predisposition and to be characterized by high levels of circulating allergen-specific IgE.
The problem is that since the 1950s, there is accumulating evidence of individuals with clinical symptoms of hay fever (allergic rhinitis), asthma and eczema (atopic dermatitis) lacking high IgE and familial history () ( ).
Such assessments suggest that atopy may have been coined using subjective, poorly delineated criteria, and that its continuing usage serves to confuse and obscure our proper understanding of immune dysregulation.