You mentioned a down comforter… and this is my expertise.. so here goes…
skip to bottom if you want just the readers digest version..lol.
Yes it COULD be the down comforter… if it was a relatively inexpensive one… I say that because its possible that it was filled with chinese down. Chinese down isnt that bad.. but the quality of it is so flaky to say the least.
First there are hundred maybe thousands of “down factories in China”... mostly actually brokers. Who only care about one thing.. reaching a price point. So what they do is… lets say Mr. Big Box Retailer wants. x amount price/value.
Well… what Chinese down companies are known to do is… sweep up dust and dander .. the bottom rings of the down that falls from the machine.. it has weight.. they will claim say a 20ounce down product.. but its mostly feathers, and all that other particles that are essentially worthless…..
which to make a long story short… you have the wonderful opportunity to breath in.. and think that you are allergic to down… when its actually:
Dust and dander.
Essentially… if you dont want to read my wall of text:
Get rid of the cheap down comforter.