Strange ... I'm with Kagey here, first one has to check what she reacts to. A visit to a doctor specializing in allergies seem useful, they do test of many substances and can find offending ones.
Sometimes it's better with different mediums, like solids or oil forms. Unfortunately, few perfumes come in this form. You can also wear stuff on clothes, then change clothes when you go home. This won't work when you go out together, but it will work at other times.
When I developed hay fever as a teenager, I was sent to an allergist and he did scratch tests on 50 potential allergens. I reacted to 48 of them. There was obviously no way I was going to be able to avoid all of these things which actually made things easier. I had desensitizing shots for a while but I'm not sure they made much of a difference. Fortunately, only one or two of these allergies were serious so I just learned how to live with them. Mostly this means taking antihistamines at peak periods during the year which has been pretty painless.