allergy

Term:  allergy

Origin: Anc Greek άλλος/allos(=other, different) + έργον/ergon (=work, reaction)

Coined : by pediatrician Austrian Clemens von Pirque 1874–1929) who along with Bela in 1906 described the condition among some of his patients where hypersensitivity to certain common injections, particularly smallpox vaccinations manifested itself for unknown reasons.  

Clemens von Pirque (1874–1929)

In contrast to the widely accepted use of the word "allergy" today concerning specific immunologic hypersensitivity reactions against harmless foreign substances, allergy in Pirque's sense was a general term likewise increases and decreases of the reactivity as "hyper-" or "hyposensitivity reactions". In addition  Pirquet  mentioned, that the change of reactivity does not only depend on exogenous factors but also on endogenous ones.

Definition: an abnormal reaction of immune system to foreign substances (allergen) as microorganisms, pollens, drugs and certain foods. Symptoms of allergy include usually skin rashes and sneezing.

Sources: Huber B. 100 years of allergy: Clemens von Pirquet - his idea of allergy and its immanent concept of disease. Wien Klin Wochenschr. 2006 Oct;118(19-20):573-9.

Richard Wagner Clemens von Pirquet, discoverer of the concept of allergy     N Y Acad Med. 1964 March; 40(3): 229–235.