All those night sweats don't just evaporate, you know — in fact, sweat is just one reason beds can be prime places for fungi to grow. One type of mold, Cladosporium, grows on damp mattresses and can lead to asthma, pneumonia, and a fungal infection called Onychomycosis, which can cause skin lesions and crumbling toenails (vom).
Even worse, "several icky infections or rashes can be transferred through dirty bedding, such as Tinea Cruris (a fungal infection that affects the skin on the genitals, inner thighs, and buttocks — AKA jock itch), Tinea Versicolor (a fungal infection that causes small, discolored patches of skin), or the tough-to-treat 'super bug' Methicillin-resistant Staphylococcus aureus, or MRSA, caused by a type of staph bacteria that's resistant to most antibiotics," says Cricco.
A study executed by mattress company Amerisleep this past August revealed the nightmare-inducing statistic that sheets left unchanged for even one week have 24,631 more bacteria than a bathroom doorknob. BRB, throwing a load of linens in the laundry. Right. Now.