I'm no doctor, but I know a few things about people's clutter: it makes people (including me) sneeze, itch, and sometimes BREAK OUT in a rash.
True.
I see it almost every time I help a client declutter: we start moving boxes out of the guest room or pulling dozens of hangers-full of clothes out of the master bedroom closet. "Aaaaachoooo!" Sniffle sniffle. Scratch scratch.
If you're not using something often enough so that it takes up storage space and does nothing for you but gather dust, attract bugs and mice, mold, mildew, and rust, then IT'S TIME TO LET IT GO.
For your health. It just might be making you sick.
Quite literally.
Now go get rid of some of it. You'll feel so much lighter and breathe freely when it's gone!