There’s nothing nicer after a long day than snuggling up with the perfect pillow that envelops your head in comfort. But you know who else loves pillows? Dust mites.

To a dust mite, your pillow is heaven, filled with the tasty dead skin cells that they love to feast upon. And one of a dust mite’s favourite season is right about now: spring and summer, because the only thing dust mites love more than skin cells, is heat and humidity.

You’ve probably never seen a dust mite; they are mostly invisible to the naked eye and hundreds of them can live in just one gram of dust. They are found wherever there’s dust -- which is to say, pretty much all over the house, but they hide very nicely in carpeting and upholstered furniture and thrive in warm environments such as bedding, which tend to trap heat and humidity.

While dust mites sound disgusting, they don’t bite and don’t carry disease. For the most part, they are as harmless as any of the other microbes we have on our skin and in our bellies. But the tiny little feces of dust mites contain an allergen that can set off asthma or sinus problems in those with dust allergies.

DUST MITE ALLERGIES

According to the Asthma Society of Canada, one in five Canadians has respiratory allergies that cause something called “perennial allergic rhinitis”: year-round runny nose and sniffles typically caused by an allergy to dust mites, pet dander, or mould. The rate is even higher among those with asthma; 75 to 80 per cent of them also suffer from allergic rhinitis.

Dust mites can infest all kinds of pillows -- feather, down, microfiber, or polyester foam. That means notone type is immune to them.

The Asthma Society recommends that those diagnosed with dust mite allergies should invest in mite-proof pillow and mattress covers, which are made of a fabric similar to typewriter ribbon with a tight weave that does not allow mites to penetrate.

But a study a few years ago by the non-profit Cochrane Review found that the covers may not do much. The review looked at 54 studies involving 3,000 asthma patients and found that no physical intervention was effective at reducing dust mite exposure. They found that the level of allergens is so high in most homes that what remains even after the use of mite-proof protectors is still high enough to cause allergic reactions.

Noah Farber, the director of public affairs at the Asthma Society of Canada, says it’s not possible to avoid allergens 100 per cent. “So we encourage our patient community to do everything you can to minimize exposure to triggers,” he told CTVNews.ca.

He says the protectors create a barrier to keep old mites in, and stop new mites from getting in.

“They are certainly not the only solution but they can be a contributing factor to helping to reduce allergens,” he said.

Farber adds his group advises those with asthma and dust mite allergies to replace their pillow every five years and their mattresses every 10 years, and use air purifiers where they can.

WHAT ABOUT THE REST OF US?

So do the four in five of us without dust allergies need to worry about dust mites? Probably not, but that doesn’t mean we don’t still need to periodically replace our pillows.

Christine Magee of Sleep Country Canada told CTV’s Canada AM not long ago that there is no hard and fast rule about when to toss your pillow. Generally, if you’re consistently waking up with a sore neck, or having a tough time moulding the pillow around you the way you like, it’s time to get a new one.

Another way to decide if your pillow is beyond help: fold it in half, and if it doesn't spring back into shape within 30 seconds -- even after it’s been washed and dried -- it should be replaced.

WASH PILLOWS OFTEN

Yes, you can wash pillows and yes, you should. Toss them into the laundry at least two or three times a year to get rid of dust, sweat and saliva stains -- more often if you suffer from dust allergies.

There are lots of guides on washing pillows, including this one from the maven of housekeeping Martha Stewart, but essentially, a little detergent and Borax to neutralize sweat smells is all you need. Almost all pillows except foam ones can go in the wash. Just be sure they are fully dried to eliminate all leftover moisture.

Since foam pellet and solid foam pillows cannot go in the dryer, they should be regularly vacuumed or periodically replaced.

WASH THE OTHER STUFF TOO

Duvets and comforters should also be washed a few times a year too to get rid of dust mites, and yes, even down-filled duvets can go in the wash (check the care label to be sure). Because they are heavy, it’s best to go a laundromat and use the large-capacity washers there. Same goes for king-size comforters, which are probably too big for a home washer, say housekeeping experts.

If you suspect you have dust allergies, the Asthma Society of Canada recommends washing sheets, pillowcases, and mattress protectors every single week, because dust mites multiply in just a matter of days. Dry the bed linens in a hot dryer, instead of on a clothesline, because while air-drying saves money, the linens can pick up pollen, which many with dust allergies are also allergic to.

OTHER TIPS TO REDUCE DUST MITES

The Asthma Society of Canada offers a few more tips for minimizing dust mites: