I already knew that!
Of course, the immunology department was mostly AIDS related, which made me feel even more of a fraud:-) But the doc was very nice and spent the time to chat to me properly and get a good background. He asked all about my medical background - absolutely no problems of any kind, no major illnesses, conditions or diseases, Im a non-smoker (ex, but nearly 10 years now), I rarely drink, I don't have a childhood history of allergies, neither my parents nor my own house are overly cleaned. Its just not right!!! He checked that it was cats, and I said I was pretty certain. He thought he should do a skin test to be sure, and to check if there was anything else.
So I went next door and let a nrse stick a needle in my arm 8 times! It was only a little nedle, and not comfortable, but not really painful. Then I had to wait 15 minutes. THAT got painful, as my arm turned bright red, with four massive weals. It was REALLY itchy!
Back to doc 15minutes later to be told I'm allergic to cats (I knew that), grasses, house dust and dogs (a little). Discuss de-sensitisation as being completely inappropriate (2 mornigs a week in hospital for 6 months, then one a month for three years - I don't think so) and decide that my best bet is just to avoid cats as much as possible. i knew that too. I get some pretty leaflets to tell me not to work as a vet, cleaner or gardener, and to tell all my friends to kill their cats (well, OK, it didn't actually say that....)
So a whole morning used up to be told what I already knew - stay away from cats, don't sniff dust and take anti-histimines a lot.