Here are a few common myths:
1. You’re more likely to get lice if you’re dirty
“Head lice has nothing to do with hygiene,” says Andrew Bonwit, a pediatric infectious-disease expert at Loyola University Health System outside Chicago. “It has to do with whether the person was exposed to someone with head lice.” Bonwit says a louse, which is “about the length of George Washington’s nose on a quarter,” doesn’t have discriminating tastes: It wants warmth for its eggs and a regular “blood meal.” It doesn’t matter if the dish is dirty or clean.
2. Your pet can carry lice
Lice feed only on humans. Fleas and ticks are another story.
3. Lice can jump and fly
No. They just crawl. That’s why kids are so much more likely than adults to have lice: They often touch heads when interacting, whether playing or talking or sleeping together at slumber parties (which are top-notch settings for lice transmission). A few lice can quickly scuttle over hair to a new head while, say, kids press close to take photos, snuggle up to watch a movie or share a pillow. While adults can get lice from their children, they rarely are the family members to bring the bugs home. (As Bonwit points out, “In the typical office, there’s probably not a whole lot of hugging going on.”)
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 Great Falls in the 1960s, he says, “I never heard of anybody who had lice. Now they’re very, very common.”
6. You can suffocate lice
Eckert says she’ll show up for house calls and parents will come to the door with their child’s hair covered in petroleum jelly, wrapped in cellophane and topped with a shower cap. “They read online somewhere that you can suffocate lice with Vaseline, olive oil or mayonnaise,” she says. “They get dubious results at best, and it’s not going to kill the nits.”
7. If you have lice, your head will be itchy
Many people with lice don’t itch. For those who do, the itchiness may not begin until a few weeks into the infestation. Since head scratching isn’t always present as a warning sign, many experts suggest that parents do periodic lice checks on their children.
