Bear in mind that allergy tests are not altogether reliable. symptom diaries are much better guides, especially if you can control the variables (eg by elimation diet. I know, i know, not so easy with this sort of thing, though)
Interesting that you often, but not always get rections at the salvo. That variance might help to pin down the cause. Cleaning/disinfecting chemicals spring to mind straight away, but it might be something less obvious . If you can find out what they use and when they use it ( both on building and also maybe on stock? ) that might just reveal the trigger, in conjunction with a symptom diary. It might also be worth keeping a diary of every little change at work, When do delveries arrive? who are you working with today? (you might be allergic to their perfume, cat dander on their clothing... ) what activity are you doing? in which room? including logging visits to the toilet- there would be loadsa chemicals in there ( Me i get reactions just to flushing my freaking toilet or running the taps, whenever chlorine levels in the water supply are particularly high. Something else to bear in mind). Really tedious, i know, but often well worth the trouble.
In any case, best of luck with this, Ren.
