Do you have a dehumidifier? I keep mine set at 40 and it runs most of the time.
We have leather furniture as dust mites live in upholstery and I steam clean the rugs (but probably not often enough).
My daughter changes the bed linen usually. I just have a sneezing fit if I do it. I've found that the only thing that really helps me is old-fashioned Piriton.
Feeling uneasy with tradespeople in the house.