Head lice facts to reassure you during an outbreak

Mother using a fine comb to get the lice out of her daughter's hair

The first sign is usually head scratching around the sides and back of the head.

Lice are then confirmed by using a comb to part the hair.

Lice will run when exposed, but some will be sluggish, as their leg tarsae (toes) hook around individual hairs,” says The Ohio State University’s resident “Bug Doc,” David Shetlar, PhD, a professor emeritus in the Department of Entomology.

Head lice infestations are most commonly detected when students return to school in the fall after summer break. They’re especially common in elementary schools, preschools and day cares, but an infestation can happen anytime.

It’s estimated that 6 million to 12 million children between the ages of 3 and 12 get head lice each year.

They can be confirmed by parting the hair back to check to see if there are lice or their white eggs attached to hair strands.

Head lice are about the size of a sesame seed and will appear white with a dark area running down their middle. That dark area is the ingested blood that’s visible through the clear exoskeleton, Dr. Shetlar says.

“If the lice have been active for some time, they will attach their eggs, called nits, to the hairs. In dark hair, these white eggs are easy to spot, but in blonde hair, they can be more difficult to see,” he says.

Learning that you or your child has lice can feel overwhelming. While lice may be annoying, rest assured that they’re not dangerous. Here’s what to keep in mind.

Contracting lice is common

Head lice have been crawling around the earth since the dawn of humanity, and they’re found on heads worldwide.

Lice eggs take 6 to 10 days to hatch, and then 5 to 8 days to develop into adults, Dr. Shetlar says. After a couple of days, the adults mate and females begin producing nits, up to 8 eggs per day for 14 to 16 days before dying.

An initial infestation usually occurs when an adult female moves onto a new host. Lice are most commonly acquired through head-to-head contact, sharing of hair combs and brushes, or sharing head coverings like hats or scarves.

Lice aren’t dangerous, but they are contagious

Head lice can cause itching and loss of sleep. It’s true that head lice thrive on human blood, but they aren’t known to spread disease.

“As a longtime dermatologist at Ohio State, I’ve certainly seen my share of head lice,” says Benjamin Kaffenberger, MD, a dermatologist at The Ohio State University Wexner Medical Center.

There are three types of lice in humans, all of which feed on human blood consumed through the skin. Interestingly, only the body louse is known to transmit human to human diseases – most notably typhus, he says.

“Body lice, which we only see rarely but are seen in mass overcrowding, wars and refugee situations, are not adapted to human hair but rather are typically found on seams of clothing,” Dr. Kaffenberger says. “The most common form of lice we see is head lice, which transmits no diseases.”

Lice affect people in all socioeconomic classes

Lice are just out for your blood, which they need to survive. All humans are fair game.

Lice cannot jump, fly or swim

Lice move by crawling. The speed of lice is less than four inches per minute, Dr. Shetlar says.

“Unlike fleas, lice do not have jumping legs, but each leg is equipped with a hook-like claw that is very good at grasping hairs,” he says. “Once one claw has been hooked on, the louse can hang on and crawl down to the skin.”

Having lice doesn’t mean you’re dirty

Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice. Those six-legged tiny insects actually prefer clean hair.

Lice is most commonly spread among girls, who are much more likely to share brushes and accessories such as scarves, caps and scrunchies, Dr. Shetlar says. Head lice don’t seem to be comfortable off head hairs, but they will occasionally move through the fibers of scarves, hoodies and knitted hats. We suspect that children touching heads while taking a selfie are commonly transmitting head lice, he says.

Lice aren’t spread through bedding, Dr. Shetlar says. However, kids sleeping together or with their parents can readily spread the lice person-to-person when they touch heads together. If a person in a family is found to be infested, there is a high probability that someone else in the family also will have them.

Your pet won’t give you lice

Lice like human blood, not warmer pet blood. Dogs, cats and other pets don’t play a role in the spread of head lice. Head-to-head contact with an already-infested person is the most common way to get head lice.

Lice cannot thrive alone in your home

Head lice and their eggs, or nits, soon perish if they’re separated from their human host. Adult head lice can live only a day or so off the human head without blood for feeding. Young lice, or nymphs, can live only for several hours without feeding on a human. Nits generally die within a week away from their human host and cannot hatch at a temperature lower than that found close to the human scalp.

One kid never gets lice

Even though you may remember the name of the one kid who was singled out for getting lice in grade school, that one kid wasn’t the culprit of all lice and was likely not the only spreader of the lice. Lice are passed from one person to another, to another, to another...

Children with lice should stay at school and return the next day after treatment

According to the Centers for Disease Control and Prevention, students diagnosed with live head lice do not need to be sent home early from school. They can go home at the end of the day, be treated and return to class after appropriate treatment has begun. Nits may persist after treatment, but successful treatment should kill crawling lice.

Talking about lice is good

Even though it might make you involuntarily itch, talking about head lice is a good thing. It helps dismantle the shame associated with getting lice and normalizes this very normal condition. Contacting other parents whose children may recently have played with your children will help stop the spread of lice and help keep your kids from contracting lice again.

“Lice are not a social disease — merely blood-sucking parasites, like mosquitoes,” Dr. Shetlar says. “Everyone talks about mosquito bites but stay hush-hush when it comes to head lice. The more people are aware that these little parasites are around, the faster infestations will be detected and controlled.”

Lice can be treated with medicine, combing and patience. There are many over-the-counter medications, such as permethrin, in addition to stronger, prescription-strength treatments for lice. There also are pesticide-free methods.

“Over-the-counter products usually have permethrin, a pyrethroid insecticide. If two treatments using these shampoos or heat ointments haven’t seemed to work, you may be dealing with a pyrethroid-resistant population,” Dr. Shetlar says. “This is the time to consult a physician to get a prescription that uses another active ingredient.”

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