4. Your house can get infested with lice.
While scientists agree that lice almost always spread by crawling from head to head, they're less sure how often they travel from head to pillow to head. The bugs "probably don't voluntarily leave a scalp," says Dale Clayton, a lice expert and biology professor at the University of Utah in Salt Lake City. "Because if you think about it, that's dangerous for them. But they may get brushed off from time to time."
Eckert says she tries to reassure clients that "Lice are very good at holding on to hair. And they are not microscopic. You're going to see them if they're on a pillow."
She also says there's no need to wash everything in a home where lice have been spotted; she'll tell people to wash their bedding not because there are bugs in the bed (there probably aren't — and if there are, they're dying) but because lice leave droppings, which look like tiny dark specks. "You don't want to be sleeping on lice excrement," she says.
5. You need special over-the-counter shampoos to get rid of the lice and nits.
Shampoos such as Nix and Rid kill live lice — but not always and not all of them. Many lice have developed resistance to the most common active ingredients, permethrin and pyrethrins. And they don't kill all of the nits.
In fact, use of these products has led to super lice, bugs that are developing a resistance to some insecticides. Already this year, at least one U.S. school district has reported an uptick in cases of super lice. "Evolutionary resistance has gotten much worse in the past 10 or 20 years," Clayton says. When he grew up in the 1960s, he says, "I never heard of anybody who had lice. Now they're very, very common."