THAT is an awful thought, especially if they were very severe. I find that Dylan makes my eyes water and I sneeze so guess I have some allergies - have always had seasonal symptoms but must not be that bad because I tolerate them. I just cannot imagine NOT having my cats. I think I would just deal with it - wear a mask when brushing then, use Hepa filters and air purifiers - just deal with it the best I could. Anything to keep my cats. I guess if they were so severe as to be life threatening - I would have to deal with that and rehome them..but that would be a rare case I think.