As far as I know "the" is used something already mentioned.
Why do you use "to have the sniffels"? I don't get why these two expressions use different articles.
The following are typical symptoms of a cold or the flu or flu (without any article)
I have a sore throat
You have a high fever
He has a runny nose
She has a bad coughWe've got a bad cold
We've got bad colds
They've got the sniffles (colloquial)
They've got the sneezes (colloquial)
“I've got a sniffling nose” is idiomatic, but not I've got sniffles, for some reason the definite article, the, is required. A bit like saying someone has the flu (although “I have flu” is also possible to say).
Well, I think "a cold" is singular whereas "the sniffles" is plural even though it's regarding one thing--a head cold. Plural nouns in English never take an indefinite article, but they can take a definite article.
I think this is what you were asking about. I hope I've read it correctly. Take care and good luck!
