When it comes to lice, one thing
we can count on is controversy:
Is it true these insects have become
resistant to lice shampoos?
Do any of the alternative treatments work?
no-nit policies effective?
By John Hoffman
THE ISSUE: LICE SHAMPOOS
What we've heard
For five years or
more, parents, teachers, camp directors and daycare operators have been
saying lice have grown resistant to pediculicide shampoos - the standard
drugstore remedies. Other experts say the big problem is people aren't
using the pro-ducts properly, and kids are becoming reinfested after
Now scientific evidence shows parents and others
were right. If you do a Google search on head lice, the first two sites
that come up are the National Pediculosis Association (NPA), a
Massachusetts-based non-profit group that's against lice shampoos like Nix
and R&C, and the Harvard School of Public Health. Harvard entomologist
Richard Pollack was lead author of a recent, well-publicized study on the
resistance of lice to permethrin-based shampoos. (Permethrins are the
synthetic equivalents of pyrethrins, pesticides derived from chrysanthemum
flowers. These are the active ingredients in most lice shampoos used in
Here's what Pollack posted on the Harvard site:
"Head lice sampled from children who were chronically infested and treated
multiple times with pyrethroid shampoos tend to be resistant to
permethrin." However, he also says, "This should not be interpreted as
meaning that all (or even most) head lice are resistant to permethrin and
related compounds. Permethrin and pyrethrins remain the treatment of
choice for newly identified infestations."
On the other hand, Deborah Altschuler, executive
director of the NPA, says there is no grey area. "Tests have shown that
lice from American children are solidly resistant to permethrin."
John Clark, an entomologist and pesticide
toxicologist at the University of Massachusetts, has also studied the
resistance of lice to permethrin and he says that not only is the
resistance there, it's likely to increase. "In our study, lice sampled
from Panama, where permethrin is not used, succumbed to it very quickly,
but 50 to 80 percent of the American lice either survived or took a lot
longer to die, which suggests a significant number would survive normal
treatment." Clark adds, "Obviously, neither our study nor the Harvard one
sampled the entire louse population of the US, but we did look at children
from five different towns and found similar resistance in all cases. And
studies from the UK, Argentina, the Czech Republic, France and Israel have
found the same thing - in fact, those countries appear to be ahead of us
in terms of resistance.
"We've seen this happen with many other
pesticides in the agricultural sector," he continues. "The farmers would
say the products aren't working and the pesticide companies would say,
'You're not using the products properly.' What happens is that some lice
are resistant to begin with and they, obviously, tend to survive
treatments that are not 100 percent effective. So when you use pesticides
in this situation, you are essentially selecting the few resistant ones
that exist naturally to reproduce the next generation. The proportion of
resistant bugs tends to increase over time. We saw that in agriculture and
the same thing has happened with lice treated with permethrin."
What we know
permethrin-based shampoos kill some lice, but there is good reason to
believe they won't kill all the lice, all the time. Neither will shampoos
containing lindane, another pesticide; these are still available over the
counter in Canada, although they have largely been abandoned because
permethrin is considered safer. (Lindane has been banned in California for
treating lice and scabies, and in some 40 countries due to environmental
concerns about its use as an agricultural pesticide.)
Lice shampoos alone won't
do the job.
THE ISSUE: ALTERNATIVE TREATMENTS
What we've heard
treatments are shampoos based on herbs or essential oils - tea tree oil,
for example - which claim to kill or immobilize lice. Some purport to have
enzymes or other substances that loosen the glue that keeps the nit stuck
to the hair shaft. Then there are the wacky products, like Neon Nits. This
is a spray that reportedly makes the nits glow so they're easier to see.
The Robi Comb is an electric nit comb that claims to kill lice with
Picton, Ontario, resident Wendy Oakley is one of
a number of entrepreneurs who have developed their own products. Her
Thursa Herbal Shampoo is a concoction of cider vinegar, five culinary
herbs, Castile soap and a vegetable shampoo. Oakley says she got the idea
from an old herb book that belonged to her mother. "This is based on
remedies they used in the Middle Ages," she says. Oakley can't quite
explain why her product works, but says, "It stuns the lice so they stand
up on end on the hair shaft and the cider vinegar collapses the nits. So
both lice and nits are easier to remove."
Neither Pollack nor Altschuler have tested
Oakley's product, but they are skeptical of most similar claims.
Altschuler has had some products tested by experts on animal adhesives,
and has yet to find one that's unlocked the secrets of nit glue. Pollack
concurs: "I've performed some limited work to evaluate the claims that
certain products dissolve or degrade the glue; I remain unimpressed."
Some people have reported success drowning lice
by applying olive oil, mayonnaise or Vaseline to the hair and leaving it
there for several hours, usually covered with plastic. These theories
haven't been clinically tested, although Bernice Krafchik, a paediatric
dermatologist at Toronto's Hospital for Sick Children, says almost
anything that plugs the spiracles (breathing holes) of lice may kill or
incapacitate them. Some products like olive oil may ease nit removal, not
because they loosen the glue, but because they help a nit comb go through
What we know
In the absence of
clinical trials, as is the case with most of these treatments, it's
difficult for consumers to tell which, if any, actually work, and whether
they are any safer than lice shampoos. These, at least, have been
subjected to clinical scrutiny.
Buyer beware. Check the
product out. Has it been tested? Ask to speak to a satisfied customer. If
it makes health claims, it should have a DIN (drug identification number),
otherwise it has not been approved by Health Canada for therapeutic use.
THE ISSUE: MISDIAGNOSIS
What we've heard
Some observers say
lice infestations are epidemic, but Pollack maintains misdiagnosis is
common, and many children are treated unnecessarily. "It seems clear to me
that the most frequently treated kids - and adults - don't have lice in
the first place," he says. Pollack's lab invited people to send in samples
from suspected lice cases. He found that almost 40 percent of the samples
were either hair debris mistakenly identified as nits or, to a smaller
extent, other bugs (book lice, mites, bedbugs, etc.). Of the real nits,
about half were either hatched or contained a dead embryo and were
therefore incapable of producing a live louse. Overall, just over half of
the samples contained evidence of an actual louse infestation, and only
half of those indicated a recent active infestation (live lice or viable
nits). This was not a controlled study, but it does underscore the
possibility of misdiagnosis.
This will come as no surprise to parents who
have looked for nits and lice for the first time and are astounded at the
number of things in their child's hair. Dawn Mucci, of the Toronto-based
Lice Squad, says, "Lots of things get mistaken for nits - dandruff and
other debris, even sand and art supplies."
Nits can go undetected as well. In a Belgian
study that compared traditional scalp inspection to wet combing (using a
conditioner, a magnifying glass and a fine-tooth comb), 30 percent of the
children who were identified as having nits from a scalp inspection
actually didn't have them, and 10 percent of those found not to have nits,
actually did. The study concluded that wet combing was the more accurate
What we know
Nits and, to a lesser
extent, lice are harder to identify than people think.
If you're not completely
sure, get a second opinion and ask to have your child assessed with the
wet-combing method. Don't use lice shampoo unless you're certain your
child has lice.
THE ISSUE: NO-NIT POLICIES
What we've heard
This is one of the
biggest fights of all. Should children be required to be nit-free before
they return to school? Pollack says he has yet to see a shred of evidence
that no-nit policies have any appreciable effect on the incidence or
prevalence of lice. "In my experience, these policies are unjustified,
misapplied and cause much greater harm than the lice themselves. Head lice
are merely a nuisance. The no-nit policies deprive kids of educational
opportunity and are a financial burden to the parents."
Karen Tilley, president of a Canadian company
called LiceBusters, scoffs at this: "You'll notice that the people who are
saying lice are just a nuisance aren't the people who are dealing with
them," says the former Toronto resident, whose company operates a
toll-free lice information service, sells lice removal kits and counsels
people to stop using louse pesticides. "It seems to me that the removal of
no-nit policies is a good way to ensure that people keep buying the
pediculicide shampoos, which often don't work very well to begin with."
Altschuler's position is that getting nits out
is a key aspect of head lice control. "We don't really like the term
no-nit policy," she says. "This isn't really about excluding children from
school. It's about setting a standard that puts education first, before
outbreaks, and encourages frequent screening. If most families use this
approach, then the system can be there to assist the kids whose parents
don't have the resources to do it."
What we know
Not all nits will
produce lice - some are "dead" and some are already hatched. The question
is: Can you tell the difference? It only takes a few viable nits to keep
the cycle alive. As for no-nit policies, they probably would help reduce
the spread of lice if they were supported by competent diagnosis (which
appears not to be the case) and treatment.
Removing as many nits as
possible seems like the one way to ensure lice and all their potential
progeny are gone. Proper equipment is important.
PULLING IT ALL TOGETHER
Here's what to do if you get that dreaded note
Make sure it's really lice. Ask an
experienced lice checker to go over your child's wet head with a lice
If you decide to use a lice shampoo,
follow the directions carefully (including the second treatment). Don't
leave the product on longer than indicated and don't use it over and over
and over. Finally, use the shampoo with the understanding that there's a
significant chance that it might not kill all the lice. Herculean efforts
to eliminate lice from clothing, bedding and furniture (apart from normal
washing and vacuuming) are most likely a waste of time, since lice can't
live for more than 24 hours without a blood meal and can't jump or fly.
Get the lice and nits out by hand. "Until
you manually remove these things, they're going to stay in your hair,"
says Deborah Altschuler. "This approach is less noxious than repeated
chemical treatments and, if done properly, more likely to be successful."
The best tool, according to Altschuler is the
LiceMeister, a nit comb which originated in Germany. "We were skeptical at
first. We've had so many products sent to us," she says. "But when we
finally got around to trying it, we were blown away with what the comb
pulled out." What it didn't pull out was hair. The comb is made from
highly polished stainless steel; it has longer, more tightly spaced teeth
and goes through more hair with each pass.
If picking out nits and lice by hand sounds like
too much work - it can easily take an hour or more every day - some
parents now have the option of hiring someone to do the job. The two most
prominent Canadian nitpickers are Karen Tilley and Dawn Mucci. Tilley
began by treating a friend and before long was helping three or more
families a week. Mucci has now taken over the in-home part of the
business, called the LiceSquad. If you live close to Toronto, Mucci or one
of her associates will come to your home and treat your family for $55 an
hour, plus travel. Tilley now concentrates on her toll-free lice
information line and the marketing of her kits (which start at $55). The
most popular one sells for $135 and includes Tilley's own
essential-oil-based lice treatment, a magnifying visor, a booklet and the
If lice outbreaks are chronic in your child's
classroom, screen your own child regularly every week. This may help
you catch an infestation before it gets out of control.
THE FACTS OF LICE
Lice are greyish-brown crawling insects (about
the size of a sesame seed) that feed on human blood. They live for up
to 30 days on the human head and are usually found around the nape of
the neck or behind the ears. They don't live on pets and they can't
survive off a host for more than about 24 hours. Louse eggs (nits)
are tiny and pearl coloured. They stick to the hair shaft with a glue-like
substance and take about eight days to hatch. Lice reach sexual
maturity nine to 12 days after hatching; they can lay up to six eggs per
day and about 100 in total.
published in Today's Parent , April 2002