It’s sometimes assumed that clothing with a price tag still dangling from the sleeve can skip an initial wash. Someone else may have tried it on, sure, but they didn’t run a marathon in it. Why not just throw it in the closet as soon as you get home?

One big reason: lice. As The Independent reports, Donald Belsito, a professor of dermatology at Columbia University Medical Center, told NBC's Today show recently that clothing fresh off store racks can harbor infestations of lice, scabies, or fungus.

You might be familiar with head lice as the dreaded insects that occupy the scalp and give school health monitors cause for concern. Head lice can be transmitted via clothing and other fabrics, and anyone who tried on a shirt or dress before you did can be a carrier. While they only live for one or two days without a blood meal, that’s still enough time to cause problems if something is being tried on frequently.

Scabies is far more insidious. The mites are too small to see, but the allergic reaction they cause by burrowing into your skin to lay eggs will be obvious.

Both scabies and lice can be treated with topical solutions, but it’s better to kill them by washing new clothes in hot water. A good soak can also get rid of formaldehyde, a common chemical used in fabrics to help ward off mold in case stock gets wet in transit. Formaldehyde can cause allergic skin reactions. For all of these reasons, it’s best to hit the washing machine before those new pants ever hit your hanger.

[h/t Independent]