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If changing your bed sheets is at the bottom of your household chore list (you know, right along with matching socks and scrubbing the shower’s grout), consider this: The skin cells that you shed in a day can feed 1 million dust mites.
That’s right: One million dust mites can feast on the dead skin cells you produce in a mere day — and when you hop into bed, plenty of them end up in your sheets.
Freaked out yet? Dermatologist Alok Vij, MD, talks dead skin, dust mites, bed bacteria and how to keep your skin safe when you lie down to sleep.
The nitty gritty (and kinda gross) details
The average person sheds a gram and a half of keratinocytes (largely made up of the protein keratin) daily, Dr. Vij says. Visually speaking, that’s about three-eighths of a teaspoon full of dead skin.
“Any kind of friction will chafe off the outer layer of your skin cells,” he explains, “so a lot of it is shed when you’re making contact with your sheets in your bed at night.”
You’re actually never alone in bed
As if simply rolling around in your own discarded skin isn’t enough, Dr. Vij says those skin cells (along with the oil and sweat from your skin, and even saliva!) can be a breeding ground for bacteria and dust mites that live on your sheets, mattress and pillows.
Dust mites are eight-legged relatives of the spider, too small to be seen by the naked eye. They don’t bite, like bed bugs do — in fact, they don’t even have teeth or mouths — and they don’t burrow under the skin, like scabies do.
But even if you don’t mind sharing your sleeping spot with these itty-bitty bedmates, dust mites can still present problems. They live on every continent on Earth except Antarctica, and many people in the U.S. have a dust mite allergy.
“That can lead to itching and trigger asthma flare-ups, seasonal allergies or rashes if too many dust mites come in contact with your body,” Dr. Vij explains.
Dead skin in bed = bacteria in bed
Bacteria love your skin. In fact, Dr. Vij says, there are more bacterial organisms in our bodies than our own cells — and the skin is one of bacteria’s most commonly inhabited areas.
When dead skin cells are left to rest in your sheets, bacteria can thrive. Then, when you lie back down in a bacteria-laden bed, you open yourself up to the possibility of folliculitis (inflammation, infection or irritation of the hair follicle) or new or worsening eczema.
Eczema, Dr. Vij explains, is one of the most common types of skin rashes, affecting everyone from young infants to the elderly. It’s driven by a combination of the dryness of your skin and overactive bacterial colonies on your skin
“By allowing those bacteria to live in harmony on your sheets and get on your skin when you hop in bed, you could be making your eczema worse — or allowing it to start in the first place,” he says.
Your furry best friend’s unwanted guests
There’s one other reason, aside from warm weather, why you might want to wash your sheets more often than twice a month, Dr. Vij says — a very cute, four-legged reason.
If you’re letting your dog sleep in the bed, take note: Pets are common harbors for fungal organisms that can cause skin issues in humans. These include simple infections such as ringworm, as well as more aggressive infestations such as scabies, which is caused by mites that can live on dogs and be transmitted to humans.
“There are a number of other parasites, too, that can be transferred from pet to pet parent, so make sure you’re washing your sheets often,” Dr. Vij concludes.
How to keep your bed as clean as possible
Ultimately, Dr. Vij says, the risk of getting a bad bacterial infection under your skin is pretty low. But it’s still a good idea to practice good bed linen hygiene so your own bacterial ecosystem doesn’t get out of whack.
In addition to washing your sheets regularly, consider this your excuse to leave the bed unmade for a little while each morning. Give sweaty sheets a chance to dry by not pulling up your comforter ASAP , which will reduce the moisture that dust mites and bacteria need to proliferate.
Some more good news: Your other bedding isn’t as high-maintenance as your begging-to-be washed sheets.
“Blankets and pillows don’t need to be washed as frequently,” Dr. Vij says, “but skin cells, bacteria and dust mites can definitely travel and live on your pillow or in your blanket. So at least every six months, they need to be washed.”
Still, don’t think of it as a bad chore. It has a substantial upside: “The washing process fluffs your pillow and distributes your blanket’s filling more evenly. That’s helpful for making your pillows and blankets as comfortable as possible for their whole life.”