WATCH: The seething mass that shares your bed
A VIDEO revealing how your bed can become the perfect breeding ground for dust mites takes a microscopic look at what we could be getting into bed with each night.
Filmed by the Ohio State University and Acarology Lab, the clip shows millions of writhing mites which are about a quarter of a millimetre long and known to cause allergies in some people.
As seen in the footage, the mites are surrounded by their own yellow faeces, of which they produce about 20 droppings a day.
According to Allergy UK, mites live off human skin scales, partially digested by moulds, and tend to thrive in humid environments.
So as our mattresses, duvets, pillows and carpets accumulate human skin cells, dust mites multiply in these feeding reservoirs.
In two years, 10 per cent of a pillow's weight will be made up of dust mites and their droppings.
Home hygiene expert, Dr Lisa Ackerley, told MailOnline: "Humans shed half an ounce (14g) of skin a week and a lot of that will be in the bed.
"Dust mites like warm moist environments; the bed's the perfect environment. They reproduce so there will be about 10 million per bed."
Adding to an appealing environment for the microscopic crawlers is the fact that often people are away from home during daytime hours so they shut windows. This causes moisture to stay in the house.
While the creatures themselves are harmless, their faeces and body fragments can trigger allergic reactions which prompt the body to release histamines to attack the allergen.
They can cause eczema and hay fever, and estimates suggest dust mites may be a factor in asthma for up to 80 per cent of people who have it.
Dr Ackerley added: "They can cause rhinitis, a cough, dry eyes. They can disturb sleep. People with other allergies can have them made worse.
"People might think they just have a cold the whole time. Dust mites really are an issue."