Doc Dispels Common Myths About Head Lice

Parents should be reassured that personal hygiene has nothing to do with the problem

Although lice do not cause serious physical harm, they can result in a lot of emotional distress because many people still mistakenly believe they are a sign of poor hygiene, an expert explains.

Head lice bite into the scalp to feed on blood, but these bites are usually not painful. Still, a lice infestation can strike fear in families for a number of reasons, including the stigma of being deemed "dirty."

A lice infestation, however, is not a reflection of a person's cleanliness, according to Dr. Andrew Bonwit, a pediatric infectious disease expert at Loyola University Health System in Illinois.

"Personal hygiene and socioeconomic status have nothing to do with having or transmitting head lice. The head louse is an equal-opportunity pest," explained Bonwit in a university news release. "The infestation is usually a nuisance and almost never a serious problem in itself."

There are other common misconceptions about lice, Bonwit pointed out. In order to ease parents' fears, he dispelled the following myths:

• Myth: Pets spread lice. "Animals are not known to carry head lice nor to transmit them to people," Bonwit said.

• Myth: Sharing personal items spreads lice. "Although it's probably best not to share such items as combs, hairbrushes and hats, these do not seem to transmit the pest," Bonwit added. "Transmission of lice seems to occur only by direct head-to-head contact from one person to another."

• Myth: Kids with lice should be sent home from school immediately."The American Academy of Pediatrics does not endorse 'no-nit' policies that exclude children from school because nits are present," Bonwit noted. "In fact, even the presence of mature head lice is not considered a valid reason to exclude children, only a cause for prompt referral to the physician for treatment."

• Myth: Lice carry disease. "Head lice do not transmit serious infectious disease," Bonwit explained.

Although lice often cause a big stir, they are tiny and often hard to spot. "Lice are very small, about the length of George Washington's nose on a quarter," said Bonwit, who is also an assistant professor of pediatric infectious disease at Loyola University Chicago Stritch School of Medicine. "The lice produce eggs, called nits, which become strongly cemented to the host's hair shafts."

Nits look like small, dark spots on the side of the hair shaft. Although the infestation isn't painful, it can be itchy, Bonwit cautioned. "Sometimes the patient has been so itchy that he or she scratches the scalp to the point of minor skin infections and even causing some enlarged lymph nodes on the back of the neck or behind the ears," he said. "While these changes may alarm parents, they aren't directly harmful."

The U.S. Centers for Disease Control and Prevention reports that up to 12 million lice infestations occur each year in the United States among children aged 3 to 11 years.

"Parents and school staff may become understandably upset by outbreaks of head lice, but it is important to remember that if the problem occurs, it is treatable, although repeat applications of medicine are usually needed," Bonwit said.

The most common lice treatment is over-the-counter or prescription shampoos or lotions that must be applied to the scalp, left on for a specified time, then rinsed off. Often a fine-toothed comb is also needed to remove nits to prevent further infestation.

"The life cycle is about seven days from the laying of the eggs to the hatching, so a second insecticide treatment is recommended, after the first application," Bonwit advised. "If the treatments are used as directed, problems other than scalp irritation are unlikely to occur."

When Lice Come Back

You carefully combed out the nits (lice eggs), applied and reapplied lice treatment as directed, and washed all the bedding and clothes. You thought your home was (finally) lice-free. Yet, the pesky mites keep coming back.

There are two reasons for a recurrent lice infestation:

• The lice treatment you used didn’t work.

• You or someone in your family came in contact with lice again.

Treatment Didn’t Work

Treatments might not work for a couple of reasons. First, studies have shown that lice can be resistant to pesticide treatments that have been used in some geographical areas.  

Second, female adult lice lay up to eight eggs a day. Over-the-counter lice treatments and prescription ones kill live lice and their eggs (nits), but they might not catch all of them. Because of the life cycle of lice, over-the-counter and prescription treatments may require two treatments, 7-9 days apart. If you don’t reapply the product within the correct number of days, lice eggs can lurk behind and hatch later.

To be most effective, follow up prescription or over-the-counter treatment by combing through the hair for two weeks to rid the head completely of lice.

Someone or Something Else Gave Lice Back to You

You can get rid of lice on your head and in your home only to have it crawl back onto you or your child at daycare, school, or the gym. You might not be able to control the environment outside your home, but these tips can help keep lice away:

• Avoid head-to-head and hair-to-hair contact. This is the way head lice most commonly spread. Think about events like kids’ slumber parties, sleepover camps, and sporting events such as wrestling.

• Don’t share hats, scarves, hoodies, or other clothing.

• Don’t share hair ribbons, barrettes, combs or brushes. (Studies suggest girls are more likely to get lice than boys).

• Don’t share towels.

• Don’t share beds, sofas, rugs, pillows, or stuffed animals with someone who has or recently had lice.

How to Keep Lice from Coming Back

The CDC and FDA say you don’t need to spend a lot of time and money cleaning the house after a lice outbreak. Head lice are bloodsuckers. Once they fall off the body, they only survive for a day or two.

5 Ways to Lower Your Odds of Getting Lice

You’ve never had lice and want to make sure it stays that way. Head lice is very common among kids between ages 3 and 11. If you’re a parent, teacher, or caregiver of a child this age, lice are more likely to find their way into your home.

You can have lice and not yet know it. Lice eggs (nits) are very hard to see and may not cause itching at first. It’s not always possible to keep these mites away, but you can take a few simple steps to reduce your risk. Here are five things to know about preventing lice.

1. Watch Your Head

Lice crawl onto the body. They can’t fly or jump. They most often spread with head-to-head contact. That means you usually must be close to someone with lice to catch it. Avoid activities that involve hair-to-hair contact as much as possible.

2. It's Nice to Share, But Not Always

That hat on the store rack might look tempting and make for a great selfie, but think twice before you try it on. You can get lice if you share hats, hoodies, towels, beds, and pillows with someone who has or recently had it. Sometimes, lice spread on combs and brushes. Such “shared contact” is uncommon, but can happen. Lice can live for about a day or two after falling off the body. To prevent lice, never share things that touch the head.

3. Don’t Lend an Ear

Lice don’t often live on hard surfaces like plastic, but they can sometimes hang out on ear buds for a short time. To lower your risk of catching them, don’t share headphones at home or at the gym.

4. Avoid the Comfy Couch

It might be nice to sit on the plush sofa at the doctor’s office or library, but ask yourself this: Who sat there before you? Lice or lice eggs (nits) can live for about 48 hours on upholstered furniture and rugs. A safer bet is a wooden or plastic chair. Stuffed animals are a hideaway for lice, too.

5. Do Your Laundry

Worried you may have been around someone with lice? Lice die when exposed to temperatures greater than 128.3°F for 5 or more minutes. Prevent a lice outbreak by tossing your clothing, hat, jacket, scarf, gloves, and any other items into the washer. Use hot water (130° F or higher), and then dry on high heat. Soak your combs and brushes in the wash, too. Can’t wash an item? Place it in a plastic bag and put it in the freezer for 2 weeks.

Parents, Schools Overreact to Head Lice, Expert Says

Aug. 24, 2000 -- The start of the school year can mean more than just back-to-school shopping trips and first-day-of-class jitters; for many children, it also means creepy, crawly head lice. Even hearing the words makes most people wrinkle their noses in disgust. But are the strict measures taken against head lice -- such as the so-called "No Nits" policy that bars children with even one louse egg from attending school -- warranted, or are they overkill?

For one scientist from the Harvard School of Public Health, society has definitely gone overboard, over-diagnosing, over-treating, and over-worrying about a minor nuisance that doesn't even qualify as a public health issue.

"We are dealing with head lice: They don't cause disease, they don't transmit anything, and we think they are much less contagious than people believe," says Richard Pollack, PhD, an instructor of immunology and infectious diseases.

Pollack and his team of researchers recently published a study in the Pediatric Infectious Disease Journal that showed that in about 40% of cases, head lice are incorrectly diagnosed, leading to unnecessary treatments and unnecessary absences from school.

Pollack invited people who visited a web site that provides information on head lice to submit specimens of items that they considered to be lice or nits. The researchers examined the samples under a microscope within two days of receiving them. Each sample was identified by the species of louse and its life stage (egg, nymph, or adult). A person was considered infected if their sample included at least one adult or nymph louse, or a louse egg capable of hatching.

The researchers received more than 600 samples, each containing from one to 100 or more objects. Lice or their eggs were found in 60% of the samples; other critters, such as beetles, mites, and bedbugs, were found in 5%. The rest contained other debris, including dandruff, scabs, fibers, dirt, and knotted hair.

Slightly more than half of the samples that actually did contain lice or nits had a living louse or egg capable of hatching (indicating an active infestation); the other half were either hatched eggs or dead eggs.

How Do You Know If You Have Them?

The thought of lice might give you the creepy crawlies -- and with good reason. When these tiny mites infect the scalp and skin, they trigger intense itching and may even create a rash around the hairline.

There are different types of lice. The type you have depends on the part of your body that’s affected:

• Head lice affect the scalp.

• Pubic lice (also called “crabs”) affect your genital area.

• Body lice affect other areas of the body and are often found in seams of clothing.

This article will focus on head lice, a very common condition among kids in elementary and middle school. About 6 million to 12 million of them get it every year. Head lice are most active at night. They can cause such intense itching that your child could lose sleep over it.

It’s uncomfortable, but lice won’t make you sick. They don’t spread disease and they’re not a sign that you’re dirty. You can get lice even if you shower regularly and have super-clean hair. These pesky creatures don’t fly or jump -- they crawl over to the closest head they can find. This is called head-to-head contact, and most people get lice this way. But they also can spread onto hats, helmets, combs, bedding, pillows – even ear buds. Young children may get or spread lice when crawling on rugs.

It’s important to know the early signs of lice. Then you can take steps to keep your child comfortable and keep the mites from spreading throughout your home.

Identifying Lice

These pests are a type of insect called a parasite. They need human blood to live. Head lice usually stay close to the scalp and behind the ears. You might also spot them on the eyebrows and eyelashes.

Female adult lice lay six to eight eggs a day on your scalp, and they spread from there. There are three forms of lice to watch for:

• Nits, or lice eggs. They’re very tiny -- about half the size of a pinhead. They’re hard to see. The oval-shaped eggs often look yellow or white but may be the same color as your hair. They stick like glue to the end? First 1-2 inches of hair shaft closest to the scalp (not the end) and are hard to remove. You may confuse them with dandruff or flakes from hair spray build-up. Head lice nits usually hatch in 8 to 9 days. When they do, they leave behind clear shells, which remain stuck to the hair shaft and appear more grey in color.

• A nymph is a baby louse (singular for lice). It’s what hatches from the nit. It feeds on the blood on your scalp and keeps growing for 9 to 12 days. Nymphs (and adult lice) move quickly and avoid light. Mites begin to appear in your hair, on your skin, and on anything your head has touched. Itching might not start right away.

• Adult lice are about 2 to 3 millimeters long, about the size of a sesame seed. They’re tan or grayish-white. The color can be lighter or darker, depending on the shade of your hair. Adult lice have six legs with claws at the end that allow them to latch tightly to your hair. Typically, adult head lice live 30 days when stuck to your head. If they fall off, they die within 1 to 2 days.

If you spot lice, tell your child’s school so they can properly clean classroom items and stop the spread. The CDC says lice aren’t a medical hazard, and most health departments don’t require that you report it. But local school boards make their own school lice policies. Check with your child’s school to find out its policy.

Don’t pull your hair out over head lice

So-called “super-lice” are big news now, just in time for children to go back to school. While that news may be somewhat overblown, as any parent who has been through one will tell you, a lice infestation can be a time-consuming and worrisome health issue. One of the bigger concerns for parents is that if their child is diagnosed with lice, they will have to stay home from school or daycare, something that recent guidelines have stated is NOT the case.

Here are six important facts about lice to keep in mind:

1. Anyone can get lice.

   Lice are not related to cleanliness. Anyone can get lice if they are in prolonged, close contact with someone else with lice. Lice only infect people—not pets—and cannot hop or fly. They spread by crawling from one scalp to another scalp. It is very uncommon to get lice from hats or brushes or combs since they cannot survive off the scalp for more than 24 hours.

2. If your child has lice, he/she’s actually had them for a while.

   The characteristic itch on the scalp, back of the neck or behind the ears is an allergic reaction to lice saliva. It often takes three to four weeks for that reaction to start.

3. Regular scalp checks are the best way to help keep lice away.

   According to the American Academy of Pediatrics, here’s how to check your child for lice:

   • Check your child in a brightly lit room.

   • Part the hair and check your child’s scalp.

   • You are trying to find either crawling lice or eggs (called nits) on the hair. Live lice are small insects (OK, that’s a little gross, we admit), about the size of a sesame seed (2 to 3 mm). They are hard to see because they move fast and avoid light. Nits are quite small (less than a millimeter) and appear pearly/white, almost like a grain of uncooked rice. They will be firmly attached to the hair shaft very near the scalp.

   • You can also wet the hair, and comb it out with a fine-toothed comb. After combing you can wipe the comb on a wet paper towel, and check the comb and the paper towel for nits.

   Nits can be confused with dandruff or dirt, so if you are unsure check with your pediatrician.

4. Your best bets for treating lice are lotions and combs.

   If your child has lice the American Academy of Pediatrics recommends treatment with one of several topical lotions that will kill the lice and possibly even kill the eggs.

   The first choice is an over the counter (OTC) lotion containing 1 percent permethrin. This choice is generally very effective, but if it doesn’t work there are prescription lotions that have each been tested and are safe to use on children. Depending on your pharmacy and insurance plan, some of these lotions can each be expensive.

   Sometimes parents decide to avoid any chemical treatments, and although there are other options, none has been proven to work. One approach is to pick out all of the eggs by combing damp hair with a fine-toothed comb. This can be challenging because of the time it takes to remove eggs from each hair shaft over many days, especially if a child has fine, long hair.

   Other methods include suffocation, meaning the application of either petroleum jelly or other thick preparations such as mayonnaise or olive oil. This method is rarely effective, and the ointments can be hard to remove from the child’s hair. Never use kerosene or gasoline or products meant for animals on your child.

   All household members should be checked for lice and nits and treated accordingly. Given that most household members are in close contact with one another, it is prudent to have a low threshold for treating all household members, even parents.

   You might have seen recent news stories suggesting that a) treatment-resistant lice are more common than ever, and b) parents shouldn’t use the usual first-line, over-the-counter  treatments anymore. To those stories I offer one caveat: The study behind them was funded by the maker of a prescription lice treatment. Let the reader beware.

5. Lice are not very hearty.

   Lice can’t survive off the scalp for more than a day, so they can’t live for very long on any objects. Also, since they can’t hop or fly from person to person, they are only contagious by scalp-to-scalp contact. This is good news.

   To rid your home of lice, you don’t need to do multiple deep cleans or throw away items. And you don’t need to spray with any pesticide. You just need to clean objects that have been near a child’s head for the past three days (e.g., hats, towels, pillow cases, stuffed animals, hair care items). Lice can’t survive in heat, so any item should be washed in hot water and dried in a hot drier. Any item that can’t be washed can be dry cleaned, vacuumed (in the case of furniture) or sealed in a plastic bag for two weeks.

6. Children with lice CAN go to school.

   According to the American Academy of Pediatrics and the National Association of School Nurses, lice and nits are no reason to exclude a child from school, daycare or any activity. These organizations have taken this position for two reasons:

   • As I mentioned above, by the time your child gets diagnosed she likely has had lice for three to four weeks, and likely got them from school or daycare. Thus, excluding a child from school or childcare does very little to prevent the spread of lice.

   • Head lice are not a dangerous medical illness that would warrant any kind of quarantine.

The low-down on head lice

Around 10 years ago, my family got head lice—and I thought we might have them forever.

I will never forget it. My head had been itchy for a while; I tried dandruff shampoo but it didn’t help. One day, desperate with itching, I asked a colleague at work if she’d check my scalp for me. “Claire,” she said, “you’ve got head lice.” I called home, and told my husband to check himself and the kids. They were infested too.

By the time I got home, my husband had bought permethrin cream rinse and treated everyone. I immediately globbed the stuff on my scalp for the allotted time and used the little plastic comb in the box, combing out some of the nits (and lots of creepy-crawly black bugs). We washed all the bedding and clothes, scrubbed all the brushes and combs, tossed the stuffed animals in the dryer. We were relieved—but within a day or two, it was clear that we were still infested. A week later, according to the instructions (and what I’d learned in medical school), we did it again—to no avail. Those bugs were undaunted; they had no intention of leaving our heads.

Our experience is becoming remarkably common. Head lice have been around for thousands of years (they’ve been found on Egyptian mummies); they are strong, resourceful little buggers, and develop resistance to chemicals used to get rid of them. Which doesn’t mean you shouldn’t try pyrethrin or permethrin, the treatments you can pick up at the drug store; it just means that you shouldn’t be surprised if they don’t work.

We get head lice from other people with head lice—head-to-head contact does it best, but they can also be spread by shared combs, brushes, hats, or other head accessories. They can hang out on bedding or upholstered furniture for a short time, so it’s easy for them to spread within a household. While they don’t fly or jump, kids at school (especially preschool or elementary school) often get close enough and share things enough that outbreaks are common. And until they are gone from everyone, they can keep spreading. Each female louse lays around 100 eggs, that hatch eight days later; once those lice start laying and hatching, well, you can imagine the math (I’m getting itchy again writing this!).

So it’s not surprising that people would go looking for stronger and better cures for head lice, and this month there was a study published about two of them: malathion, an insecticide, and ivermectin, an antiparasitic drug. The researchers used them on people who still had head lice two to six weeks after using permethrin or pyrethrin (my family would have qualified!), and found that 85 percent of the malathion group got rid of their lice, and 92.5 percent of the ivermectin group got rid of theirs.

Sounds great, right? Well, there are two problems to consider. First, as we’ve said, head lice are resourceful creatures. If we start using these treatments frequently, it’s likely that the lice will begin to be resistant to them (the researchers were careful to point out that these treatments should be reserved for cases where nothing else has worked). Second, and more importantly, both malathion and ivermectin can be toxic—usually just if used incorrectly, but even correct use could cause side effects in some people.

So what do you do if your child (or your family) has lice? There are lots of remedies out there, most of which don’t work or are dangerous (and some of which, like petroleum jelly, can be very messy). The Harvard School of Public Health has lots of great information on remedies (and on head lice in general), but what I recommend, and what ultimately did the trick for us, is the simplest treatment of all: combing. It’s not a quick fix, but it works. Here’s what you need to do:

• Buy a good lice comb, one with long, metal tines that are very close together (drug stores and pet stores sell them).

• Get out any tangles before you get started, or the lice comb will just get stuck. Detangling spray can help; if you do the whole thing in the tub, putting conditioner on the hair helps the comb go through (and you can rinse out the conditioner afterward).

• Separate the hair into sections. Start at the scalp where the bugs and live eggs are, and comb through to the end. Rinse or wipe the comb after each pass (check to see what you got first).

• Comb every day until you haven’t seen any eggs or live bugs for at least eight to 10 days (since that’s how long it takes an egg to hatch).

Not only is this approach completely non-toxic, if you go at it with the right attitude (i.e. a fun and patient one), it can be quality family time! Try telling stories (you can take turns adding to them) or making up songs—or just use it as a time to catch up and find out what’s going on in your child’s life. That’s what we did, and after two weeks of bonding—I mean combing—we were finally lice-free.

When fighting lice, focus on kids’ heads, not hats or toys

I recently attempted a technically demanding “around the world” braid on my kindergartner. On my sloppy and meandering approach to the South Pole, I discovered a loathsome sight that scuttled my circumnavigation — a smattering of small, brownish casings stuck onto hairs.

I tried to convince myself that I was looking at sand. She’s always covered in sand! But I’ve spent enough time around insects to know that I was looking at something biological. Bad braid abandoned, I began combing through, looking for more specks. And I sure found them: Lice eggs, or nits, that were glued onto the hair next to the scalp, and precisely one live bug.

Today, I am delighted to report that our outbreak is over. (Although with three young children, our situation will probably swing between “having lice” and “waiting to have lice again.”) Our first brush with the little buggers sent me into full research mode, and I’m now armed with a deeper understanding of lice habits and preferences. In the interest of streamlining your next lice experience, I offer below some little-known and helpful facets of lice life.

The best way to spot lice and their tiny nits is with wet combing.

Compared with spot-checking the scalp, pulling a fine-toothed metal comb through hair that’s slick with conditioner turns out more critters. 

Pepper-sized nits can range from white to brown in color and are glued to single hairs. These suckers are on tight: You might need a fingernail to pop them off. Live nits need to be close to the warm scalp to survive; casings that are farther than a centimeter away from the scalp are probably empty or contain dead eggs.

Once hatched, a live human head louse, or Pediculus humanus capitis, grows no larger than the diameter of a pencil eraser. It’s grayish white. And its favorite — and only — food is blood from a human scalp, which it slurps several times a day.

Super lice laugh at pesticides.

More and more lice can withstand permethrin or pyrethrins, the pesticides inside most of the boxes you’ll find in your panicked drugstore run. And there’s not much evidence for other treatments, including mayonnaise and tea tree or lavender oil. And please don’t even think about gasoline.

Lice burrowed onto heads are surprisingly hardy, even underwater.

In one series of experiments, researchers watched lice cling to cut hair in regular water, seawater, salt solutions and even chlorinated water. The pests didn’t respond to a poke, either, researchers found.

Another study looked at lice pulled off the heads of people in France. After six hours underwater, all the lice in the experiment (188 of them) were happily alive. About half of the lice were still alive after 24 hours underwater. Hardy, I say.

But: Lice are wusses when not on a head.

Off their favorite spot, adult lice quickly dry out and starve, particularly in dry environments. Most are dead within 40 hours after their last meal. And it is unlikely that eggs removed from a head can yield healthy adults.

Lice aren’t all that contagious.

They can’t jump, fly or swim. Their dire need for a human head means that direct head-to-head contact, such as the type you see with little girls coloring together, is what allows lice to crawl to a new home. 

“The control of head lice should focus on the head, not on the environment,” researchers wrote in 2010 in The Open Dermatology Journal. That paper mentions a study of over 1,000 hats, worn by students who, combined, had over 5,500 lice on their heads. The heads had lice, but the hats didn’t. The risks of transmission from hairbrushes, hats, helmets and toys are really, really low. The same goes for flooring: When researchers combed the floors of 118 classrooms at a school with a known lice outbreak, they turned up no lice.

All this to say that you don’t need to wage war on your house and bag up your kid’s clothes, bedding and stuffed animals for three days. “This recommendation has no basis in science,” a 2016 review stated.

Lice aren’t dangerous.

They are gross, to be sure, but they’re not a menace to public health. Kids don’t usually get sick from lice, beyond a little bit itchy. That’s why the American Academy of Pediatrics objects to “no nit” school policies that prevent kids with lice from attending. The Centers for Disease Control and Prevention agrees, as does the National Association of School Nurses.

Lice can be a valuable commodity, in exactly one scenario:

Shrek (the real ogre in the delicious book, not the sanitized movie version) trades several of his rare lice to a witch in exchange for his fortune. It’s a great deal.

So there you have it. I’d certainly prefer to live a lice-free life, but now that I know more about these relatively harmless insects, I feel a little bit better about our prospects.