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Head lice are getting harder to kill. Here’s how to break the nit cycle

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3rd March, 2025

Wrangling head lice, and the children they infest, must be up there with the most challenging duties a parent or carer has to face. And the job is getting harder.

Com­mon­ly used chem­i­cal prod­ucts aren’t work­ing as well as they once did, mean­ing head lice are hard­er to kill.

You can still rid your chil­dren of lice – but it’s like­ly to take some patience and persistence.

Remind me, what are head lice? And nits?

Head lice are tiny six-legged insects that are only found in the hair on a human’s head – most com­mon­ly in the hair of pri­ma­ry school-aged children.

Head lice have been a con­stant com­pan­ion for humans through­out their mil­lions of years of evolution.

Lice love liv­ing in our hair. But they scoot down to our scalp up to a half dozen times a day to drink our blood.

Their claws are per­fect­ly designed to scut­tle up and down shafts of hair. But while they’re nim­ble on our hair, once they’re off, they don’t last long –they’re clum­sy, unco­or­di­nat­ed and die quickly.

The term “nits” actu­al­ly describes the eggs of head lice. They’re often the first sign of an infes­ta­tion. And with one louse lay­ing more than 100 in their month-long lifes­pan, there can be a lot of them.

file 20250226 32 h6at8z.jpg?ixlib=rb 4.1
Head lice live for around a month.
logika600/Shutterstock

Can they spread diseases?

No. Head lice are annoy­ing and their bites may cause skin reac­tions. But Aus­tralian health author­i­ties don’t con­sid­er lice a health risk. There is no evi­dence that head lice can spread pathogens that cause disease.

The stig­ma of head lice infes­ta­tions can be greater than any direct health con­se­quences for infest­ed children.

Why do my children always pick up lice?

From child care through to pri­ma­ry school, it’s like­ly your child has had a head lice infes­ta­tion at least once. One Aus­tralian study found the infes­ta­tion rate in Aus­tralian class­rooms ranged from no cas­es to 72% of chil­dren affected.

Girls are more like­ly to be car­ry head lice than boys. Long hair means it’s eas­i­er for the head lice to hitch a ride.

Children work in class
One study found that in some class­rooms, almost three in four chil­dren had head lice.
CDC/Unsplash

Head lice don’t jump or fly, they move from head to head via direct contact.

Head lice come home with your chil­dren because they spend time in close con­tact with oth­er chil­dren, hug­ging, play­ing or crowd­ing around books or screens. Any head-to-head con­tact is a path­way of infections.

Rules dif­fer slight­ly between states but in New South Wales and Queens­land, chil­dren don’t need to be kept home from school because of head lice.

How can I keep my home free of head lice?

Keep­ing the house clean and tidy won’t keep head lice away. They don’t care how clean your bed sheets and tow­els are, or how fre­quent­ly you vac­u­um car­pets and rugs.

There may be a risk of head lice trans­fer on shared pil­lows, but even that risk is low.

There’s no need to change the child’s or oth­er fam­i­ly member’s bed­ding when you find lice in a child’s hair. Research-based rec­om­men­da­tions from NSW Health are that “bed linen, hats, cloth­ing and fur­ni­ture do not har­bour or trans­mit lice or nits and that there is no ben­e­fit in wash­ing them as a treat­ment option”.

I’ve used nit solution. Why isn’t it working?

A wide range of prod­ucts are avail­able at your local phar­ma­cy to treat head lice. Australia’s Ther­a­peu­tic Goods Admin­is­tra­tion assess­es prod­ucts to ensure that they are both safe and effective.

The prob­lem is that most of these prod­ucts are insec­ti­cides that kill the lice on con­tact but may not kill the eggs.

Also, if treat­ments aren’t com­plet­ed as direct­ed on prod­uct labels, some head lice won’t be killed.

Head lice also seem to be fight­ing back against the chem­i­cals we’ve been using against them and it’s get­ting hard­er to clear chil­dren of infestations.

So how can you get rid of them?

Mum combs child's hair
You’ll need con­di­tion­er and a nit comb.
riopatuca/Shutterstock

Don’t expect any mir­a­cle cures but health author­i­ties in Aus­tralia gen­er­al­ly rec­om­mend the “con­di­tion­er and comb” or “wet comb” method. This means you phys­i­cal­ly remove the lice with­out the need for chem­i­cal applications.

There are three key steps:

  1. immo­bilise the lice by apply­ing hair con­di­tion­er to the child’s damp hair and leav­ing it there for around 20 minutes
  2. sys­tem­at­i­cal­ly comb through the hair using a fine toothed “lice comb”. The con­di­tion­er and lice can be wiped off on paper tow­els or tis­sues. Only adult lice will be col­lect­ed but don’t wor­ry, we’ll deal with the eggs later
  3. repeat the process twice, about a week apart, to break the life cycle of the head lice.

Repeat­ing the process after a week allows the remain­ing eggs to hatch. It sounds counter-intu­itive but by let­ting them hatch, the young lice are eas­i­er to remove than the eggs. You just need to remove them before they start lay­ing a fresh batch of eggs and the infes­ta­tion continues.

While chil­dren are much more like­ly to have head lice, the real­i­ty is that every­one in the house­hold is just as like­ly to host a head louse or two. You don’t nec­es­sar­i­ly need every­one to have a treat­ment but “grown ups” should be on the look­out for lice too.The Conversation

Cameron Webb, Clin­i­cal Asso­ciate Pro­fes­sor and Prin­ci­pal Hos­pi­tal Sci­en­tist at NSW Health Pathol­o­gy and Uni­ver­si­ty of Sydney

This arti­cle is repub­lished from The Con­ver­sa­tion under a Cre­ative Com­mons license. Read the orig­i­nal arti­cle.

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