Home Remedies to Control Head Lice:Assessment of Home Remedies to Control theHuman Head Louse, Pediculus humanus capitis(Anoplura: Pediculidae)
Miwa Takano-Lee, PhDJohn D. Edman, PhDBradley A. Mullens, PhDJohn M. Clark, PhD
As the frequency and level of pediculicide resistance increases throughout the world, the need for novel solutions to controlpediculosis has intensified. The development and registration of new pesticides has become so costly that many chemicalcompanies are unwilling to pursue it and health-care providers now face a serious lack of new commercial pediculicides. Manyinfested people resort to using bhome-remedy Q approaches that have not been scientifically tested. In this article, we examinedthe potential value of six purportedly effective bhome remediesQ (vinegar, isopropyl alcohol, olive oil, mayonnaise, meltedbutter, and petroleum jelly) to treat head louse infestations and the likelihood of drowning lice by water submersion. Resultsindicated that only the application of petroleum jelly caused significant louse mortality but no treatment prevented lice fromlaying eggs. Most home remedy products did little to kill eggs, despite prolonged exposure. Petroleum jelly caused the greatestegg mortality, allowing only 6% to hatch. It was extremely difficult to drown lice, despite extended periods (i.e., 8 hr) of watersubmersion, suggesting that killing lice by depriving them of oxygen is inefficient. None of the home remedy products wesurveyed was an effective means of louse control. This suggests that when treatment failure occurs, an increased amount of timeand effort should be focused on alternative chemical pediculicides and/or manual louse removal (i.e., combing) rather thanusing any of these products. n 2004 Elsevier Inc. All rights reserved.
EVERY YEAR, AN estimated 6–12 million making head louse treatment more problematic.
people, most between the ages of 5–12 in the
Failure of over-the-counter pediculicides, despite
United States, are infested with the human head
repeated treatments, runs the risk that people will
resort to unproven and often unsafe home remedies
adversely affects the education of many school-
In this article, we tested six common home
children, because many schools have implemented
remedies: vinegar, isopropyl alcohol, olive oil,
a bno-nit Q policy, barring the return of students to
mayonnaise, melted butter, and petroleum jelly.
the classroom, until they are louse- and nit-free.
Until recently, head lice have been treated
relatively effectively with commercial pediculi-
From the Center for Vector-Borne Diseases, University of
cides, such as pyrethrins plus piperonyl butoxide,
California, Davis, CA, Department of Entomology, University of
1% permethrin, 1% lindane, and 0.5% malathion
California, Riverside, CA, and Department of Veterinary and
Animal Science, University of Massachusetts, Amherst, MA.
Health, & the Committee on Infectious Diseases,
Address correspondence and reprint requests to John D.
2002). However, within the last few years,
Edman, PhD, Center for Vector-Borne Diseases, University ofCalifornia, Davis, CA 95616. E-mail: jdedman@ucdavis.edu
resistance to commercial pediculicides has been
n 2004 Elsevier Inc. All rights reserved.
Meinking, 1999; Pollack et al., 1999) and is
Journal of Pediatric Nursing, Vol 19, No 6 (December), 2004
Both adults and eggs were treated and their
that clients used dangerous home products, such as
survival compared with identical treatment by
gasoline or kerosene, in an attempt to eliminate head
water. In a separate experiment, we tested the
feasibility of killing lice by prolonged water
their use, home remedies are old and varied, ranging
submersion. To reduce variability and to insure
reproducibility and replication, we maintained
cuoglu, 1996). Increased Internet access has head
human head louse colonies with our human feeding
louse treatment misinformation to spread without
regulation. An Internet search of bhead louse home
Clark, 2003) and tested them on our hair tuft
remediesQ yielded more than 14,000 hits.
Although anecdotal reports of home remedies
abound, only three research papers claim to have totested the efficacy of home reme
Burkhart, 1998; Meinking, 1999; Schachner,
Pediculicide resistance among head lice (Pe-
diculus humanus capitis De Geer), as reflected in
when live lice were placed directly in petroleum
product failure, has been documented around the
jelly and two kinds of hair pomades, lice were
effectively immobilized and killed within 15 min,
Harvey, & Coles, 1999; Lee et al., 2000; Mum-
cuoglu et al., 1995; Picollo, Vassena, Casadio,
Burkhart and Burkhart did not provide important
Massimo, & Zerba, 1998; Pollack et al., 1999;
experimental details, such as the number of lice
Rupes, Moravec, Chmela, Ledvinka, & Zelenkova,
tested, how much material was used per person, or
1995). Treatment failure also may be caused by
where and in what condition the tested lice
ski, & Spielman, 2000), but some resistance is
that massaging 30 – 40 g of petroleum jelly was
undeniable. A recent survey of pharmacists
beffective,Q but failed to define beffectiveQ and gave
revealed that 79–81% of users had encountered
no indication how many petroleum treatments were
resistance to pyrethroid products and 50%
reported their clients were treating themselves
other hand, reported that live adults were recovered
with pyrethroid products at above the recommen-
in all cases from schoolchildren treated overnight
with olive oil, mayonnaise, or Vaseline, beneath a
resistance is widespread, the degree of resistance
shower cap. Unfortunately, no quantified data were
is variable and can occur in pockets throughout
presented, such as the sample size of students
observed per treatment, their levels of infestation,
insecticides such as malathion are available, but
many parents are reluctant to use this formulation
In summary, there has been a failure of re-
because the application time is long (8–10 hr), the
searchers to provide quantitative results or statis-
odor is offensive, and the product is highly
tical information on whether home remedies can
control louse infestations. Therefore, there is an
have begun to prescribe boff-labelQ materials that
urgent need to quantify home remedy efficacy to
lack Food and Drug Administration approval as
properly instruct patients on safe and effective
pediculicides, such as ivermectin, 5% permethrin,
treatments. Unfortunately, few people even try to
10% crotamiton, and trimethoprim-sulfamethoxa-
rear head lice for testing, and replicated trials on
infested people are almost impossible to perform.
Only two completely nontoxic louse-removal
We performed three experiments to investigate the
methods exist: shaving the entire head or manually
(1) effect of home remedy treatment on live lice,
removing lice with a comb. The former guarantees
(2) effect of home remedy treatment on egg
complete success, but it is rather extreme and can
viability, and (3) likelihood of drowning lice by
prolonged water submersion. By performing these
Faced with recurring infestations, parents often
studies, we hoped to settle the controversy on
purchase unproven products advertised on the
whether home remedies are effective and assist
Internet as ball-naturalQ cures or rely on various
health-care providers with valuable treatment op-
tions or information, especially in the face of pedi-
quarters of pharmacists surveyed reported evidence
remedy product (melted butter, vinegar, isopropyl
Each of our procedures was an experimental
alcohol, or olive oil) or deionized water (control)
design, comparing either six experimental groups
for 5 s. Nonliquid products (mayonnaise and
with one water control (home remedy studies) or
petroleum jelly) were applied by dabbing hair
four timed treatments with one control time
tufts with lice into 1.5-ml microcentrifuge tubes
threshold (submersion experiment). To minimize
containing the product, which was enough to
experimental variation, we used lice from our
completely cover the hairs. Treated hair tufts with
lice were then placed onto filter paper in a Petri
Mullens, & Clark, 2003). Each colony originated
dish (35 mm in diameter), covered, and placed in
from a different geographic region: San Bernardino,
an incubator (318C, or 888F, 60 – 80% relative
humidity). We collected three different sets
Ecuador (EC), and Niadup and Ticantiki, Panama
of outcome measures: (1) at 8 hr, the proportion
(PA). The CA colony is resistant to pyrethroids,
of live insects and female fecundity (the number of
whereas the EC and PA colonies are susceptible
eggs produced per female) was recorded; (2) at 24
hr, the proportion of live insects was again
Based on Internet searches and discussions with
recorded; (3) proportion of eggs hatching and
parents and school nurses, we chose six home
hatching rates were recorded for several days
remedy products to test: mayonnaise (Miracle Whip
following the treatment. Survival at 8 hr was
Light, Kraft Foods North America, Glenview, IL),
chosen as the observational threshold, because
petroleum jelly (Longs Drugs, Walnut Creek, CA),
control lice, remained robust, and suffered no
salted butter (Challenge Dairy, Dublin, CA), white
mortality. The 8-hr period also represented the
distilled vinegar (Stater Bros. Markets, Colton, CA),
approximate duration of an overnight treatment
isopropyl alcohol (70% by volume, Aaron Indus-
and provided ample time for treated lice to recover.
tries, Lynwood, CA), and olive oil (Trader Giotto’s
Survival data (proportion of test population still
extra virgin olive oil, South Pasadena, CA). With the
alive at 8 and 24 hr) and hatching proportions were
exception of isopropyl alcohol, these materials were
statistically transformed (arcsine of the square root)
chosen because they are considered to be common
and compared by a one-way analysis of variance
household items, relatively nontoxic, and inexpen-
(ANOVA). Significance was determined at p b .05.
sive. Isopropyl alcohol is found in most households,
Female fecundity and hatch rates were compared by
but is flammable. Deionized water served as the
ANOVA with significance determined at p b .05. If
control, acting as a harmless wetting agent. Butter
the ANOVA test revealed statistically significant
was melted above a hot plate just prior to use and
differences, then a Tukey means separation test was
was only mildly warm to the touch when applied.
used to calculate differences between groups.
Because naturally infested hosts have eggs of
Mullens, & Clark, in press), we had determined
different ages, our second experiment examined
that adult females and males were the most likely
whether home remedies affected hatching propor-
to transfer to a new host. Therefore, we chose to
tions or hatch rates. Hair tufts (n = 5– 6) with EC
focus on females for the first experiment, because
eggs (n = 12– 42 eggs/hair tuft, or 71–137 eggs/
of their larger size and ability to lay eggs; if a
treatment) of various ages were treated as de-
home remedy product could adversely affect
scribed above for live females. After treatment,
females, then it would probably be just as effective
tufts with eggs were placed on filter paper and
against other stages. Groups of five freshly fed
maintained in the incubator without washing or
rinsing until the experiment was terminated (9–10
replicates of each; 40 lice tested total) were placed
days after application treatment). Two outcome
on a clean hair tuft (c150–200 human hairs glued
measures were documented: (1) the proportion of
together at one end and cut to 1.25 cm length).
eggs hatching (observed by microscope) and (2)
After all females were attached to the hairs, lice
the proportion of first instar nymphs that were able
were treated with one of six home remedies
to open the egg but unable to exit (partial-hatch).
(experimental variable) or water (control). Hair
Hatching and partial-hatch proportions were arc-
tufts with lice were submersed into the liquid home
sine (square root)-transformed before comparison
Table 1. Survivorship and Fecundity (F Standard Error of the
comparison; the Tukey means separation test was
Mean) of Reproductively Active Females (n = 40 per Group)
All EC and PA lice treated with water (control)
for 8 hr survived with no observed ill effects. Only
lice treated with petroleum jelly had significantly
less survival (38%, 15/40) when compared with all
other types of home remedies (75–98%) ().
In all groups, 28– 43% of the lice (n = 11–17
individuals) survived 24 hr following treatment
despite starvation, and survival did not significant-
Note: Significance was determined at p b .05.
ly differ between lice treated with water and licetreated with any home remedy, F(6, 18) = 0.17, p =.98, data not shown. Eggs laid by lice treated with
by ANOVA. A comparison of means test (Tukey)
vinegar (9.1 F 0.07 days), isopropyl alcohol
(10.0 F 10.0 days), olive oil (9.0 F 0.0 days),
and mayonnaise (8.6 F 0.17 days) required a
significantly longer period to hatch than eggs laid
by water-treated females treated with water (8.0 F
In the final experiment, we investigated the
0.1 days), F(6, 24) = 11.91, p b .0001, data not
probability of drowning the lice, based on time
shown. None of the home remedies affected
submerged in water. Preliminary research indicated
reduced the hatching rate, compared with water,
that the survival of lice submersed for 6 hr and
F(6, 18) = 1.62, p = .20, data not shown.
surviving at 24 hr (from t0) was comparable to lice
starved for 24 hr (Takano-Lee, unpublished
observations). Therefore, we used the 6-hr sub-mersion time as our survival baseline (control) and
Eggs treated with olive oil, mayonnaise, and
compared louse survival against four other sub-
petroleum jelly were less likely to hatch than those
treated with water (). Petroleum jelly was
Groups of recently fed adult male and female
the most effective home remedy, allowing only 6%
lice (n = 4 –5; total of 8–55 lice treated per
of eggs to hatch, compared with an 87% hatch rate
microcentrifuge tube containing 1 ml of deionized
significant difference in the proportion of eggs that
water. Tubes were gently agitated until all licewere completely submerged and resting at thebottom. Lice were submerged for periods of 6, 8,
Table 2. Proportions (F Standard Error of the Mean) of Eggs
10, 12, or 16 hr and remained undisturbed at room
Hatching After a 5-s Immersion in Home Remedies
temperature (22–238C). At the end of the submer-
sion period, lice were removed from the water,
placed on filter paper in Petri dishes, and
permitted to recover until survival was docu-
mented at 24 hr (8, 12, 14, 16, or 18 hr later).
Outcome measures recorded were female fecundi-
ty and the proportion of lice functionally viable,
based on the ability of lice to demonstrate normal
motor coordination without twitching, lurching, or
convulsing. Proportions of surviving lice were
arcsine (square root)-transformed before ANOVA
Note: Significance was determined at p b .05.
Table 3. Proportion (F Standard Error of the Mean) of Adult
during treatment overnight might increase louse
Lice Alive After Water Submersion at Room Temperature
mortality, but is unlikely to affect eggs. Loose
shower caps may not contain all of the hair
overnight and would allow some lice to recover.
Like chemical pediculicides, no home remedy is
It appears to be nearly impossible to drown lice
on a host. Lice must be unable to respire for at least
8 hr continuously before significant mortality
occurs, and such conditions are difficult to meet
on a naturally infested host. However, if an
Note: Significance was determined at p b .05.
overnight home remedy treatment is completelyremoved, it may be possible for lice to recover,even after 12 hr. Contaminated articles, such as
partially hatched between any treatments, F(5,
clothing or linens, must be laundered at high
25) = 1.85, p = .14, data not shown.
temperatures to kill lice, because drowning for
Treating hairs did not interfere with egg laying, as
Following prolonged water submersion, only
combing, because they can temporarily immobilize
lice submerged for 6 hr were able to lay eggs,
or slow down lice and may suffocate some. For an
although egg-laying was reduced (data not shown);
oily remedy to be effective, however, multiple
therefore, no statistical analyses were performed.
treatments and a great deal of combing are required
Most lice submerged for 6 hr (n = 15) and
surviving at 24 hr were functional (), but
The fact that these experiments could not be
survival significantly decreased as submersion
performed on a naturally infested host was the main
limitation of this study, because the impact ofcontinuous blood-feeding is unknown. Most likely,mortality rates would have been reduced because
blood ingestion would have boosted energy levels
and restored life functions. However, by performing
No home remedy killed 100% of lice or eggs
the experiments in the laboratory setting, we were
after 24 hr, but petroleum jelly killed more lice than
able to use suitably large sample sizes under
any other treatment. In fact, many lice survived past
24 hr in all treatments, suggesting that lice are rather
We recommend that future studies explore the
hardy. In addition, keeping home remedy products
utility of bnaturalQ substances, such as the essential
on the hair for extended periods, or getting them off,
oils, noting with caution that such substances may
can be time-consuming, uncomfortable, and stress-
be harmful if not administered properly. Other
alternative strategies that physically stress lice, such
Although eggs laid by lice treated by a home
as elevated temperatures, occlusive compounds,
remedy exhibited delayed hatching rates, the differ-
dessicating agents, or even commercial pediculi-
ence probably was not biologically important.
cides, could be used in combination with each other
Remedies with high viscosity (i.e., olive oil,
to control louse infestations or disinfect contami-
mayonnaise, and petroleum jelly) tended to reduce
egg hatch, but nothing completely stopped it.
It is unfortunate that these simple and relatively
Perhaps by sealing the eggshell opening, they
safe home remedies were not more effective, but
deprive the egg of oxygen. In addition, the
doctors and nurses should discourage their use
befficacyQ of these viscous materials should be
because they clearly fail to eliminate louse infesta-
cautiously interpreted, because they were permitted
tions. In addition, patients should be informed that
to remain on hairs for 9–10 days; most people would
some home remedies are toxic or dangerous to
wash their hair within hours after a treatment,
apply. Alternative approved pesticides and manual
thereby cleansing the hair and nits and allowing
combing are currently the only good options when
eggs to hatch. A tight-fitting swimming cap worn
treatment failure occurs. They should be combined
with a thorough cleaning of the home environment
The authors thank the school nurses within the
San Bernardino City Unified School District andDr. David Taplin and Terri Meinking, FieldEpidemiology Survey Team (FEST), University
of Miami, School of Medicine, Miami, FL, for
Funding for this project was provided by the
their generosity in collecting head lice for our
National Institutes of Health grant R01AI45062.
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Unit I: Research Fundamentals Scientific Knowing Have you considered how you know what you know? As you sit in classes or talkwith friends, have you noticed that people differ in the way they know things? Look atsix students who are discussing the issue of "modern translations" of the Bible. Student 1: "I use the King James Version because that's the translation I grew up usi
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