According to a recent Time magazine article:
[D]ust consists of some combination of shed bits of human skin, animal fur, decomposing insects, food debris, lint and organic fibers from clothes, bedding and other fabrics, tracked-in soil, soot, particulate matter from smoking and cooking, and, disturbingly, lead, arsenic and even DDT.
I'm allergic to dust. So, if dust contains human skin, then I must be allergic to 12% of you . . . and me.
Hmmmm . . . I'm not antisocial, I'm just allergic to you. Yeah, that's the ticket.