Cats pee everywhere and many people are allergic to cats.

Allergic reaction to yellow jacket sting. 

There are also flowers that smell like rotting corpses, you should be glad your neighbors aren't growing those.For that matter there is a field across the street from me where they grow 100 acres of a plant I'm severely allergic to.

Maybe it's some other cause, like you don't digest something very well--and it makes you feel awful.Or maybe you can get some kind of medicine to make you feel better, because maybe it is not the house, but something else...like local pollen, or eating peanuts, or something.It could be anything--allergic to the neighbors dog, or squirrels, or etc...

In all seriousness though this is my nightmare since I am extremely allergic to cats.  

That's like a guy that is allergic to peanuts being told there are no peanuts in the peanut butter.

I have since discovered that I am highly allergic to it, had to go to the doc and get a steroid shot as well as oral steroids.....it's been an adventure.

Regarding deal structure, @Robin Simon is correct, lenders are very allergic to multiple lien holders.

I'm allergic to earned income anyway😎An example on one I'm buying tomorrow is seller pays remaining property taxes for the year, recording costs ($400- our state is insane), my title and escrow costs and a landscape allowance of $2800. 

You’ll only lose the guests who are allergic, fewer than those who have pets.Also, if someone even mentions they have a service dog, you can’t use that as a reason to deny them.