All Hail Baron Clemens Peter Freiherr von Pirquet

Somebody had to be the first one to identify and name the reactions that are the result of allergies, rather than the million and one other causes of bodily reactions.

That someone was Baron Clemens von Pirquet, an Austrian scientist and pediatrician.

Wikipedia says of him:

In 1906 he noticed that patients who had previously received injections of horse serum or smallpox vaccine had quicker, more severe reactions to a second injection. He, along with Bela Schick, coined the word allergy (from the Greek allos meaning "other" and ergon meaning "reaction") to describe this hypersensitivity reaction.

Soon after, the observation with smallpox led Pirquet to realize that tuberculin, which Robert Koch isolated from the bacteria that cause tuberculosis in 1890, might lead to a similar type of reaction. Mantoux expanded upon Pirquet's ideas and the Mantoux test, in which tuberculin is injected under the skin, became a diagnostic test for tuberculosis in 1907.

You'll find a reference to the Baron, along with lots of other detailed information on allergy and intolerance, in a .pdf, Allergies and Other Sensitivities, from the AmsterdamKliniak. Don't worry, it's all in English.

The procedures they talk about may be slightly different from those normally pursued in the United States, but the general information is good and useful.