How long does it take for the bumps to appear. Have just realised I am getting them at work in the late afternoon. I do have a cat but he has v rarely had a problem. One of the ladies I work with has seven cats though. Could this problem be at work?
It could be that they have travelled into work and are breeding there. I assume you are sure it is fleas and not something else like bed bugs, not saying you have them at home but they travel easily in bags.
You could try a flea trap to see if you have them at home first.