HOLD THE BUS !!!!!!!!!!!!!!!!!
DUSTMITES in themselves, are not the cause of the asthma attacks nor allergy attacks per se.
The cause is a by-product of their faeces (crap), called Der P1
Granted, you will be reducing their numbers, but the crap with the allergy causing stuff is still there.
I also agree with what has been stated about mattresses and pillows holding more dust mites and their crap than carpets and even upholstery.
After all, we spend one third of our life in that hot, sweaty, dark home for dust mites, our bed.
Regular vacuuming and an anti-allergen treatment is good.
So is taking your mattress out and letting it spend a day in the sunshine occassionaly.
Cheers,
Shorty.