How to Calculate How Long You Have Had Head Lice

The news has broken, and your kid has lice. We know the drill. Panic immediately sets in while a million questions run through your head at the same time. You’re thinking how long could you’ve had lice? How did this happen? We’re tackling the first question among many—how to calculate how long you have head lice.

Lice Life Cycle

To be able to calculate how long you’ve had lice, we’ll need to understand the lice life cycle.

• Once the lice have spread to the person’s head, the female louse will start to lay their nits or eggs; an infestation has begun.

• The first nymphs, or baby lice, will appear 7-10 days later.

• Nymphs will continue to eat and grow over the next 7-10 days.

• Before becoming adults, nymphs will molt their exoskeleton three times in order to mate. You can think of this as the louse teenager stage, based on the various molting phases the louse might be.

• During the third and final molt, the gender is determined based on what is needed for a growing colony and are now officially adults.

• Once genders are determined, the females will mate, and the life cycle begins again.

It is important to note, after the first successful lice generation, the females mate only one time and lay nits for the remainder of her lifespan. The louse lifespan is usually between 30-33 days, and females can lay up to 10 nits (eggs) a day.

Calculating How Long You Have Had Lice

Now that we’ve learned all the fun details on the life of lice let’s get down to the bottom of how long you’ve had lice. Lice infestation is typically noticed in 30 days after the nymphs have become adults and begin to mate. Female lice are larger than male lice, which means they can be easier to spot in someone’s hair. When you examine the scalp of a person with lice, you will be able to see lice at the various stages in their life: nits, casings (shell after hatching), nymphs, teens, and the adults. By understanding the life cycle of lice, if there are more nits than adults on the head, we can assume you’ve had lice for longer than 30 days. This means there has been longer than one louse life cycle on the head because the adult lice were able to lay and hatch their nits.

For a more technical calculation of how long you’ve had lice, we can measure how far from the scalp the eggs (nits) are. Female lice lay their eggs as close to the scalp as possible, and hair grows about 1 cm per month. For example, if you find nits in your hair and they are measured 2 cm from the scalp, we can calculate you’ve had lice for two months.

Avoid Catching Lice During the Spring Sports Season

Spring is in the air, sports are getting started, and kids are getting ready to put on their helmets. Helmets and hats are easy ways for lice to spread quickly, but it doesn’t stop there. Once one child on a team has lice, they quickly spread to the rest of the members of the team. So it is essential to do everything possible to help our children to avoid catching lice in the first place. By paying attention to a few details, we can put an end to lice outbreaks.

Use Your Own Helmets and Hats

During the spring, baseball, softball, and tee-ball are all in full swing. It doesn’t matter if your child is playing in the outfield or pitching up a storm; they will be wearing a hat or a helmet. Lice are surprisingly resilient and can survive for around two days on different surfaces. If there is a child on the team with head lice, sharing their equipment could easily cause others to catch lice. The best way to avoid this is by simply not using helmets and hats used by teammates.

Don’t Share Brushes

When your child is getting ready for a game, it is common to get ready with the other kids. That means getting into uniform, looking over plays, and for female athletes, putting their hair up. Sharing brushes is one of the most common ways that head lice can be spread. Avoid catching lice this spring by making sure that you bring your combs, brushes, and barrettes.

Pay Attention in Huddles

At the beginning of a game, after a break in the action, or during a substitution, huddles are everywhere in sports. Your children could be rubbing their heads against each other unknowingly catching lice. As soon as their heads touch, lice spread from player to player. It isn’t practical to avoid huddles all together in sports, but you can warn your kids to avoid catching lice by not making head-to-head contact.

Bring a Fully-Stocked Duffle Bag on Team Trips

Away games are always exciting for children taking a trip with their friends. These experiences are amazing, and we want to make sure that they are enjoying their trip and their game. However, it will be hard for your child to enjoy anything if they have itchy head lice. The best way to avoid catching lice is to ensure that your child is using their own clothes, towels, hats, and pillows while on a team trip.

Keep Everything Clean

Being safe is better than being sorry. Even if there has not been a lice outbreak on your child’s team, it is important to keep their items clean. Take extra care to make sure that their sheets, pillowcases, combs, and everything else are clean. There may be no need to worry, but it doesn’t hurt to make sure.

Parents warned over new breed of ‘super head lice’ resistant to over-the-counter treatments

Experts say people are wasting their cash forking out on products designed to kill the so-called "super lice" that no longer work.

The pesky bugs are a common problem, particularly preying on the scalps of school kids, aged four to 11.

But they have managed to evolve to become resistant to some of the treatments sold at chemists, scientists say.

Ian Burgess, of Insect Research & Development Limited, said when Lyclear Creme Rinse hit the market it "swept the board".

But, he warned, it leaves insecticide in a sufferer's hair.

While that may sound an appealing prevention measure, he said the bugs have slowly learned biologically to cope with it.

Global problem

Mr Burgess said that bugs coming into contact with the insecticide and surviving the encounter is a "worldwide phenomenon".

Research by Journal of Medical Entomology (JME) revealed that 98 per cent of head lice are now resistant to common treatments.

The 2016 study of 48 US states found that head lice were able to grow gene mutations, which helped them resist insecticides, also known as pyrethrins, pyrethroids, and permathrins.

Professor Craig Williams, of the University of South Australia, has been researching ways to outwit nuts.

Speaking to 7NEWS, he said: "Super lice would be the name we would give to lice that have become resistant to some of the treatments to kill them."

He likened the spread of the super-strength lice to antibiotic resistance - the more we use insecticides, the bigger the problem becomes.

His solution? Stick to the old trusty method.

"Cheap hair conditioner and a nit comb, and manually comb them out," Prof Williams said.

HEAD LICE FACTS

• Head lice are tiny insects that live in hair.

• Typically, they grow up to 3mm long, making them are difficult to spot.

• They can cause an itchy scalp and general discomfort as the parasites live by feeding on human blood.

• Nits are particularly common in school children aged between 4-11.

But here's some facts you might not have heard about nits...

• They can’t fly, jump or swim

• They are very unlikely to be spread by items such as combs, hats or pillows

• They don’t have a preference for dirty or clean hair – nor short or long

• They are specific to people – you can’t catch them from animals

• Once they have been removed from hair, head lice will usually die within 12-24 hours

Superbugs

Dr Sarah Jarvis, GP and clinical director of Patient.info, told The Sun Online warned of problems in recent years with topical head lice treatments.

She said: “Head lice are tiny brown-grey insects, about the size of a sesame seed, which thrive on the scalp.

"Nits are the white eggs they hatch from. These stick to the hair – usually close to the scalp – and are often still seen after treatment has killed all the lice.

"There are two main treatments for head lice. The first is strictly physical – wet combing using conditioner and a specially designed ‘bug busting’ comb.

"It’s time consuming and needs to be repeated several times - repeated every few days until you’ve had three sessions in a row where you have not seen any live lice.

"However, it is very effective when done properly and can be used regularly to check for new infestations.

"The second is to use topical treatments - lotions etc - to kill the bugs. These are divided into two main types.

"The first are chemical insecticides, which poison the lice. There have been lots of problems in recent years with head lice becoming resistant to these chemical insecticides.

"The second type is the physical insecticide. These work by smothering the lice and we have seen far less resistance to these treatments.

"Your pharmacist can advise on the treatments recommended in your area.”

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.