??Environmental allergy??

I promised someone in the Bay Area, California area that I would do some research on their issue. This is my first step.

This person is suffering a rash that they think is related to either mold (house is over 60 years old) or something left behind possibly by a pet cat (cat has been dead 6 years) They've had the house supposedly checked and been tested for allergies to no satisfactory avail.

Maybe I am not getting the whole story, but I found it strange that this would be considered as unusual because of all the stories that have been published about harmful effects of mold, etc. My question is, are any of you running patients with similar complaints and where are they being directed? THANKS