other methods:

1) buy a good vacuum, vacuum your bed and surrounding once a week

2) change your bed sheet and pillow cover regularly, like once a week

3) change your mattress every few years.

4) consider to make your house or room fully air-conditioned, without open windows and some good air-cond, the room will have very few dust.

5) if you ever buy dust mite cover, remember it must be breathable ... else it will worsen your skin condition. (but the price will not be that cheap)