>About 20 years ago when I was diagnosed with asthma (the price, I suspect, for my days as a chain-smoker), I was sent to an allergist for all the tests - both arms and shoulders, and across my back. That's when they believed that asthma was necessarily due to allergies (they know better now). Anyway, he tested me for everything he could think of, and gave me concentrated scratch tests for animals because I have cats. In the end, he seemed very put out with the fact that everything came back negative. He swore I had to be allergic to my cats, in spite of the fact that he couldn't get even a minor reaction to his scratch tests. He actually seemed quite angry about it.

Only dermatologists and alergists know less about what they are doing than the psychiatrists ;).