Oct. 14, 2005 - Fungal spores fill our pillows, British researchers report.
Science has already alerted us to the unsavory fact that tiny dust mites populate the pillows on which we sleep. But that's not the end of the gross-out, thanks to Ashley Woodcock, MD, professor of respiratory medicine at the University of Manchester, England, and colleagues.
Woodcock's team analyzed five feather pillows and five synthetic pillows in regular use for one-and-a-half to 20 years. The pillows, they report, each carried up to 16 different fungi.
"We secrete about 100 liters of sweat into a bed over a year. We do not wash our quilts and pillows, so they are an ideal place to find fungi," Woodcock tells WebMD. "And sure enough, we found them."
The Zoo in Your Pillow
Woodcock thinks fungi, dust mites, and people are probably part of a pillow ecosystem.
"You have a small zoo in there," he says. "It is thought that human skin scales in bedding are used as a food source for fungi, and the fungi are eaten by mites. And the fungi might sit on the mite feces as well."
Lest you think that Woodcock is merely warming up for Halloween, he does have a serious purpose. He studies the origins of childhood allergy. During his research, he ran across a 1936 paper reporting that bed pillows grow fungi. Since then, he says, nobody has looked at the issue.
"It may be no risk for normal people," Woodcock says. "But one in five people has a respiratory disease, and these fungi might pose a significant risk for people with asthma and patients with immune suppression."
For those not allergic, or susceptible to diseases caused by fungal infections, the populations in our pillows may actually help build up our immune systems.
"Maybe, for normal people, it is not a bad thing," Woodcock suggests. "Maybe we need fungal exposure as press-ups for our immune system. On the other hand, maybe as we've changed to synthetic bedding from feather bedding, the flora and fauna have changed, too. We don't know."
Though feather pillows do carry a lot of fungi, they don't carry as much or as many different types as synthetic pillows, Woodcock's team reports in the current online issue of the journal Allergy.
Expert: No Big Deal
How worried should we be about pillow fungus? WebMD asked indoor pollution expert William Beckett, MD, professor of environmental medicine at the University of Rochester, N.Y.
"My reaction is, 'Ho-hum. We knew this already," Beckett tells WebMD. "We culture fungus from all over the home. Wherever you look, they are there."
Beckett is not entirely reassuring.
"You can find these things everywhere and we don't know how to eradicate them," he says. "There is a sense that indoor exposure to fungi may make allergies and asthma worse for some people. We are trying to find out what we can do about this, but we don't yet know."
If there were such a thing as a mold-proof pillow -- and Beckett does not think there is -- it's not clear that people with allergies would be any better off.
"And we don't know if a little fungus is OK and a lot is worse," Beckett says.
Meanwhile, Woodcock says the current findings aren't reason to replace your pillows. After all, he points out, the finding has been -- almost literally -- staring us in the face for a very long time.
"We don't have enough evidence at the moment to throw all our bedding out," he says. "But we need to watch this space and wonder what the fungi are doing there and whether a particular kind is particularly bad."