According to Dr. Anne K. Ellis, a clinician scientist at Kingston General Hospital in Kingston, Ont., a mattress cover is the key line of defense for people with an allergy to house dust mites.
House dust mites are “microscopic insects that like to live in our mattress and pillows,” said Ellis.
Symptoms of a dust mite allergy can include waking up with a congested nose, itchy, watery eyes, sneezing and itching. Patients with asthma can also experience waking up with more chest tightness than usual.
Dr. Jason Ohayon of Hamilton Allergy in Hamilton, Ont. said that a persistent dry cough in the night and a severely itchy nose are also usually clear signs of a dust mite allergy.
“If your child comes down to the breakfast table and they’re rubbing their nose in a north-to-south direction (so much) that they have a crease in their nose… that’s a good sign that they’ve been chronically itchy,” said Ohayon. He recommends seeing an allergist to receive a formal diagnosis if any of these symptoms are present.
House dust mites are nearly impossible to extinguish completely, which is why it’s really important to have “dust mite-impermeable mattress covers and pillow covers,” said Ellis. “It’s your best defense.”
However, not all mattress covers are made equal. The type you want to look for is tightly woven, and typically advertised for people with a dust mite allergy.
“You want to make sure it’s woven tightly enough that it really prevents you from inhaling the allergen that the dust mite contains in its body and in its feces,” Ellis explained.
To all of her patients, Ellis recommends performing a water test to ensure the cover is tightly woven enough.
“You put a drop of water on the cover and it should roll back and forth like a bead of mercury,” she said.
“If it bleeds through, it means it’s not a high enough quality cover and I suggest that they replace it with a better one.”
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If you suffer from a dust mite allergy, Ellis recommends washing your bedding once a week. Ohayon extends this to include your child’s favourite stuffed animal if they’re the one with the allergy.
“Wash them in hot water and dry them on the hot setting,” she said. “This helps kill off any additional mites.”
You can further minimize your burden by removing carpets if you have them.
“Hardwood or laminate flooring make it more difficult for dust mites to survive,” she said.
Another thing you want to avoid is high humidity in the bedroom.
“We recommend keeping the humidity (…) to less than 40 per cent, because (dust mites) thrive on ambient humidity as their main source of water,” said Ellis.
According to Ellis, dust mite allergies can flare during the warmer seasons because of their affinity for more humid conditions.
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“People may think they have a ragweed allergy because they get symptoms in the fall, but really, when we skin test them, they’re only allergic to house dust mites,” she said. “We adhere to the fact that there are more dust mites around at times of high humidity.”
Ohayon said this is especially important to note because a typical remedy for congestion is to turn on a humidifier.
“They’re thought to be helpful for conditions that affect the airway… but it makes it that much easier for dust mites to grow,” he said.
Even if you don’t have a dust mite allergy, a mattress cover and washing your bedding once per week is still a good idea, said Ellis. “It’s just good practice to have a cover on your mattress to minimize how much moisture and dead human skin cells penetrate into your mattress.”
A mattress cover is an easy way to keep your mattress clean, and it will prolong your bed’s lifespan in the process.
“If you’re not sure if your symptoms are due to an allergy, asked to be referred to an allergist for a proper assessment,” Ellis said.