Taking The Fifth

As a pretty good general rule, English has a name for everything you'd care to name. (As a pretty good general rule, every language does, in fact. A language is going to invent or adopt words for everything it needs to talk about, or else what's the point?)

Sometimes, of course, we have to resort to workarounds. English still doesn't have a universally accepted term for "the person I love and live with and will probably spend the rest of my life with but am not married to". (It also doesn't have a genderless word for "he or she", although "they" is making great if nervous inroads.)

And sometimes, the word that we end up using just doesn't seem to make any sense at all, and even when we know what the point of it is, it still doesn't seem to make any sense.

I was reading some medical encyclopedia or other and came across a term I'd never seen before: "fifth disease", which is a minor childhood infection by something called a parvovirus resulting mostly in a fever, a rash, and red blotches on the cheeks.

"Fifth disease"? Well, if that isn't the most baffling name for a disease I'd ever heard. Was it named after some doctor by the name of Gerald Fifth? (No, because "fifth" isn't capitalized.) Was it...well, what was it?

I looked through my usual sources. Wikipedia was no help (perhaps I'll go in and edit it). The online dictionaries: nothing. Finally, I stumbled across a proper explanation, which is this: there was a list of the most common rash-producing childhood diseases, and the parvovirus infection simply happened to fall fifth on the list. The others were measles, scarlet fever, rubella, and some unknown illness in fourth place which was called, yes, "fourth disease".

Wouldn't you think someone might have come up with proper names for those diseases? That's the natural order of things in the medical world, which dearly loves to name and classify everything. Since the fourth disease is a mystery, it doesn't have a name, but fifth disease was called by doctors "erythema infectiosum" ("infectious redness"). Unsurprisingly, it didn't catch on; it needed a less intimidating name, and so people began calling it "slapped cheek disease" because of those red blotches that appear about a week in. It still doesn't have a snappy name like "pneumonia" or "the dose", but not every disease can be the personification of brevity.