Allergic reactions have been reported as far back as ancient times and undoubtedly predate that. Sometime around 3,500 BCE, King Menses of Egypt is reported to have died after being stung by a wasp. Britannicus, the son of the Roman emperor Claudius, was so allergic to horses that his eyes would swell up and he was not able to ride, according to the philosopher Seneca. That would have been problematic for a would-be emperor (though not as big a problem as his adopted brother Nero, who probably poisoned him).
In the early 19th century, an English physician named John Bostock was the first to recognize allergic rhinitis (in his own case, summer hay fever) as a condition distinct from the common cold. Only in 1906 was the word “allergy” coined by a doctor in Vienna—from the Greek words allos for “other,” and ergos for “activity,” meaning a reaction to something foreign.