{{{Beej}}}
Also, what beth said.
Sometimes allergies -- combined with the smaller space of an apartment versus a house -- can develop/worsen as you get older.
This is very true, vw. My father was never allergic to cats when he was younger, but by the time DH and I had a cat, he had to dose up before he came to our house. And I've never been allergic to dogs, but my parents now have an English cocker who makes me sneezy and watery-eyed every time we visit (and this despite the fact that my own dog has never caused one symptom).