1. Dust mites
Microscopic insects called dust mites are the most common allergy and asthma symptom trigger, according to the American Academy of Allergy, Asthma and Immunology. They feed on human skin flakes and tend to thrive when rooms are above 40 percent humidity and at temperatures above 70 degrees. And while they like bedding and soft furnishings the most, they can be found anywhere in the house. To ward off dust mites, allergists recommend purchasing allergenproof encasings for pillows, mattresses, and box springs, and washing linens in 130-degree temperatures every seven to 10 days. "Any place you find people where it's not supercold or really dry, you can have dust mites," White says. Unlike bedbugs, dust mites don't bite, so you won't wake up with puncture marks on your skin. "It's largely a respiratory phenomenon," says Clifford Bassett, chair of the AAAAI's Public Education Committee.
When it comes to cleaning, have someone else handle the vacuuming, or wear a mask. And use a vacuum that contains a HEPA filter or double-layered bag. Since stuffed animals collect dust mites, too, you'll need a simple way to keep your child's favorites trouble free. "Take the stuffed toy, put it in a freezer bag, and then put it in the freezer for three to five hours per week," Bassett says. Freezing the toy kills the dust mites. When purchasing other types of toys, stick with products that are washable or easy to wipe off.