Dust mites are the most important bedroom allergen. Pillows are a common place for dust mites to live. Put pillows in allergen-impermeable zippered covers or wash the pillow every week in hot water (>130 F). Avoid feather pillows opting for synthetic or Dacron pillows that can be washed.

So called "hypo-allergenic" pillows still need to be encased, as they are only made of material that is less likely to cause an allergic reaction. Dust mites are still found in "hypo-allergenic" pillows. Using encasements is the best way to create a barrier between you and dust mite allergen.