Chrysanthemum, Pyrethrin and Getting Rid of Head Lice

The male human head louse, Pediculus humanus capitis
The male human head louse, Pediculus humanus capitis | Source

Head lice have lived on human scalps since ancient times. They are a common and very annoying parasite. Although they don't cause disease, they can be extremely irritating. The flowers of some chrysanthemum species contain an insecticidal material known as pyrethrum. One of the active ingredients in this material is a chemical called pyrethrin. Pyrethrin is useful because it kills insects, including head lice, but is safe for humans and pets. It's a common ingredient in head lice treatments.

Unfortunately, although pyrethrin has been very effective at getting rid of head lice in the past, the lice are becoming resistant to the chemical. Pyrethrin is still a common treatment for head lice, but sometimes other control methods must be used. There are potential problems or difficulties with these methods, however. We really need a new treatment for head lice that is effective, convenient and safe.

A spider chrysanthemum
A spider chrysanthemum | Source

Chrysanthemums

Chrysanthemums, or "mums", belong to the family Asteraceae and the genus Chrysanthemum. Their family is also known as the Compositae. This name reflects the fact that their flower is technically a composite made of smaller flowers, which are sometimes known as florets.

There are two types of florets. The disk florets are located in the centre of the flower and don't have petals. The ray florets surround the disk florets and each contain one petal.

Mums are beautiful and popular plants. Their flowers have lovely colours and patterns and take many different forms. Some chrysanthemum flowers are flat and resemble daisies. Others have multiple layers of ray florets that are upturned and hide the disk florets. Some flowers are almost globular and look like buttons or pom poms. In some species the ray florets are narrow and tubular, making the flower look like a spider.

Chrysanthemums containing ray florets that hide the disk florets.
Chrysanthemums containing ray florets that hide the disk florets. | Source
Chrysanthemum cinerariifolium (the Dalmation chrysanthemum) is the main source of pyrethrin.
Chrysanthemum cinerariifolium (the Dalmatian chrysanthemum) is the main source of pyrethrin. | Source

Chrysanthemum or Tanacetum?

The genus is the first word in the scientific name of an organism. Some biologists think that the plants that produce pyrethrin should be placed in the genus Tanacetum instead of the genus Chrysanthemum.

Pyrethrum

The chrysanthemum that is generally used for pyrethrin production is Chrysanthemum cinerariifolium. Its common name is the Dalmatian chrysanthemum. Some people may not realize that this plant is a chrysanthemum because its flower looks like a white daisy and its leaves are finely divided like those of some ferns.

The Persian chrysanthemum or painted daisy (Chrysanthemum coccineum) is also used as a source of pyrethrin. It contains a much lower content of the chemical than the Dalmatian chrysanthemum, however. Its flower resembles a daisy and is white, pink or red in colour.

Chrysanthemums whose flowers look like daisies and produce an insecticide are sometimes known as pyrethrums because they were once classified in the genus Pyrethrum. The word pyrethrum is also used as a name for the raw insecticidal material produced by the plant. One of the active ingredients in pyrethrum is the chemical named pyrethrin. Although the word pyrethrin is often used in the singular, there are actually several types of pyrethrins.

Both dried and powdered chrysanthemum flowers and an extract obtained from them are used to kill insects. The pyrethrin is located in the seed cases of the flowers. In some countries pyrethrums are an important cash crop due to their ability to make a safe insecticide.

Chrysanthemum coccineum (the Persian chrysanthemum or painted daisy) produces pyrethrin, but not as much as Chrysanthemum cinerariifolium.
Chrysanthemum coccineum (the Persian chrysanthemum or painted daisy) produces pyrethrin, but not as much as Chrysanthemum cinerariifolium. | Source

Pyrethrin and its Uses

Pyrethrins are neurotoxins for insects. They interfere with the normal functioning of an insect's nervous system, paralyzingly the insect and often killing It. Pyrethrins kill other insects besides lice. They are appreciated for their relative safety for mammals and the fact that they are broken down by light and air. Pyrethrins generally don't persist in the environment after use.

Pyrethrin is often mixed with piperonyl butoxide, which acts as a synergist. A synergist doesn't produce a benefit by itself but makes another substance more effective. Enzymes in a louse's body normally break down pyrethrin, which may allow the insect to recover from a treatment. Piperonyl butoxide enables the pyrethrin to stay intact for long enough to produce an effect.

Pyrethrin is one of the safest insecticides for mammals and is often used as a lice treatment for pets as well as humans. Although it has very low toxicity for humans, it's not completely nontoxic. At normal concentrations pyrethrin usually creates no problems. Some people do experience an allergic skin reaction to pyrethrin, though. Inhaling a high concentration of pyrethrin can cause breathing difficulties and nausea. In test animals, very high concentrations have produced convulsions and paralysis.

A female head louse, Pediculus humanus capitis
A female head louse, Pediculus humanus capitis | Source

The Head Louse

A head louse has the scientific name Pediculus humanus capitis. Head lice are parasitic insects and feed on human blood. They have no wings and can't fly or jump. Instead, they crawl from place to place. Like other insects, head lice have three pairs of legs. Each leg ends in a claw, which resembles a hook. The claws enable a louse to cling to a hair. Female head lice are slightly bigger than the males.

The Secret Life of Head Lice

Life Cycle of a Head Louse

A nit is the egg of a head louse. Nits are very small and are white or yellow in colour. They can be mistaken for dandruff. The female louse deposits the nits at the base of the hair shafts next to a person's scalp, cementing them to the hair with a glue. The nits hatch in about a week.

A tiny nymph emerges from a nit. The nymph looks like an adult head louse but is much smaller. The empty nit stays in place, so if someone is exploring the hair of someone with head lice, the nits that they find may be full or empty.

The nymph molts to form the slightly larger second nymphal stage. This in turn molts to form the larger third nymphal stage. The third nymph molts to form the adult house louse. The time period from nit hatching to the appearance of the adult is about a week.

Life cycle of the head louse
Life cycle of the head louse | Source

How Do Head Lice Spread?

Lice are spread by head-to-head contact or by the transfer of an item that has been in contact with an infected person's head. Example of these items include hats, combs, scarves, hairbrushes, pillows and headphones. The lice can infect people of any age but tend to infect children that form close and interactive groups, such as those formed in day cares and classrooms. Becoming infected by head lice doesn't means that a person has poor hygiene. Anybody can get head lice!

A nit of a head louse; the nit was photographed after a lice treatment and is dead
A nit of a head louse; the nit was photographed after a lice treatment and is dead | Source

Symptoms of a Head Lice Infestation

Itching is the most common symptom of a head lice infestation. The itch is created by an allergic reaction to the louse's saliva. The affected person may also experience a crawling or ticking sensation. When someone examines the scalp of a person with head lice they may see red spots. Some people don't experience any symptoms from a head lice infestation.

Pyrethroids and Head Lice

Reduced effectiveness of pyrethroid treatment for head lice.

A head louse and a nit
A head louse and a nit | Source

Pyrethroid Treatment For Head Lice

Pyrethrin is frequently found in head lice shampoos and treatments. It's been a mainstay treatment for getting rid of head lice for a long time. Permethrin is a synthetic version of pyrethrin and is also a common ingredient in lice treatments. Pythethrin and permethrin are known as pyrethroids. Pyrethroids kill adult lice but not nits.

Other insecticidal chemicals are available for treating head lice. These may not be as safe for humans, however, and some require a doctor's prescription.

Lice experts say that although pyrethroids were once very successful at killing lice, they have lost much of their effectiveness. This situation is due to the development of resistance in the insects.

Due to genetic variation in the members of a species, some head lice possess a gene or combination of genes that makes them resistant to pyrethroids. When these lice reproduce, they pass some of their genes to their offspring, enabling some of the offspring to resist the insecticide, too. Gradually, as the insecticide kills the lice that are susceptible to damage by pyrethroids, a population of resistant lice becomes dominant.

The following quote was made by a researcher in reference to the current effect of pyrethroids on head lice.

The efficacy of all those products has gone way down. It started out at 100 percent, now we're down to 20 to 30 percent in recent clinical studies.

— John Clark, University of Massachusetts

Wet Combing to Remove Head Lice

This University of Nebraska-Lincoln web page has complete instructions for wet combing in addition to a description of other head lice management techniques.

How to Use a Lice or Nit Comb

A Non-Chemical Treatment For Head Lice

One non-chemical treatment for head lice that can be effective is called the wet-comb method. In this treatment a large amount of conditioner is applied to the hair. A fine toothed metal lice comb is then run though the hair to pick up lice and nits. A lice comb is specially designed; it's not just an everyday comb with fine teeth. Lice combs are available at drug stores.

The process of wet combing can be boring for the person being treated, especially if that person is a child, so it's good if they have something to entertain them while they're sitting down. Good lighting is needed so that the person doing the combing can see the hair and scalp clearly. The process involves carefully combing a section of hair and then pinning it out of the way so that another section can be combed. The comb needs to be wiped with a tissue before cleaning a new section of hair. The tissues must be carefully disposed of after use.

The wet combing method needs to be repeated every three to four days for two weeks in order to remove newly hatched lice. It's more time consuming and requires more effort than using a chemical method to control lice, but it has important advantages. It avoids the application of an insecticide to the scalp and it also overcomes the problem of lice resistance to insecticides.

Lice have been part of human lives for thousands of years. It looks like we will be fighting them for many years to come. Hopefully new and improved treatments for head lice will appear soon.

© 2014 Linda Crampton

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Comments 36 comments

klidstone1970 profile image

klidstone1970 2 years ago from Niagara Region, Canada

I'm already scratching my head! Lord, but they are disgusting. And are a lot of work to get rid of. Yuck. I can do without them, that's for sure. I do vaguely remember hearing about the chrysanthemum flower years ago and how it was used for lice. Hopefully, lice will stay out of this household... **Kim frantically knocking on wood**


billybuc profile image

billybuc 2 years ago from Olympia, WA

You always have the most interesting information. I am happy to report I've never had head lice. :)


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

I hope you and your family never get a visit from head lice, Kim! They can be a big nuisance. Thanks for the visit and the comment.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Thanks for the comment, Bill. I appreciate it. I've never had head lice myself, but I've known people who have. A lice infestation isn't very pleasant!


Faith Reaper profile image

Faith Reaper 2 years ago from southern USA

You have me scratching my head as I write this comment! Useful article, but just looking at the photos turns my stomach, as they are so disgusting to me. They are hard to get rid of for sure. Interesting about the chrysanthemums. I do hope they come up a better way to get rid of lice and soon!


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

I hope researchers discover a better way to get rid of lice, too! I certainly wouldn't want to have head lice, and I sympathize with those who do. If I forget about the irritation that they produce, though, I think that head lice are interesting creatures! Thank you for the comment, Faith.


bdegiulio profile image

bdegiulio 2 years ago from Massachusetts

Thankfully I've never had head lice. Those pictures of them give me the heebie jeebies :) Very interesting hub Linda. This was quite an education.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi, Bill. Thank you very much for the comment. I hope you never experience a head lice infestation!


DDE profile image

DDE 2 years ago from Dubrovnik, Croatia

Hmm! I knew of someone who had head live and I had to stay away from them. The comb sometimes had the live too. Great hub on this subject. You have such interesting hubs. Voted up!


SandyMertens profile image

SandyMertens 2 years ago from Frozen Tundra

I am itchy just reading this. Hope I never get it but interesting to learn about how these flowers help.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Thank you very much, DDE. I appreciate your comment and vote.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

I hope you never get head lice too, Sandy! Thanks for the visit.


Susan Zutautas profile image

Susan Zutautas 2 years ago from Ontario, Canada

I have an itchy head after reading your hub :) When my boys were small I always used tea tree oil and tea tree oil shampoo to kill the head-lice.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Thanks for the visit and for sharing the tip, Susan!


Nancy Hardin profile image

Nancy Hardin 2 years ago from Las Vegas, NV

Made my head itch before I got through the first paragraph. EWWW! When I was 6 years old and in first grade in Chicago, IL, my mother discovered I had lice. At that time there was a treatment known as blue ointment, and she slathered that on, used the lice comb, and I was a miserable little girl. We finally got rid of them, only to have me come down with them again inside of two weeks. Obviously someone as school was carrying them, so the school nurse had to inspect everyone. Those who had head lice were sent home with a note to their parents. It seemed like an epidemic at the time, but finally we were all louse free. Whew! I remember all this, because it was so traumatic for my poor mother, who never let a speck of dirt collect in our house or on our bodies. As you might expect, the first time was bad enough, but she was furious the second time around! Lots of good information here, hope it gets out to lots of folks who may need it.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

This is an interesting story, Nancy. I can understand why your mother and you were so frustrated! Thank you very much for the comment and for sharing the information.


Mel Carriere profile image

Mel Carriere 2 years ago from San Diego California

Fascinating expose on head lice and its treatment. I remember getting checked as a child, but we always thought only the ""dirty" kids got it. Great hub!


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Thank you very much for the comment, Mel! Yes, many people think that having head lice has something to do with bad hygiene, but health experts say this isn't correct. Anybody can get head lice if they get close enough to the insects to enable them to climb on to the hair.


techygran profile image

techygran 2 years ago from Vancouver Island, Canada

Hi Linda-- This is an excellent hub on lice, with a very nice presentation. I worked as a social worker in a day care for a few years. There were many "infestations" and a lot of attention to protocol, but I'm pleased to say I didn't get lice myself. Nor did my children. But that doesn't mean we didn't get cavities, colds, or flea bites occasionally when our pets were infested. Disturbingly, more for some than others, humans live very closely with all kinds of parasites. We have much to learn from them, and you have done a fine job of teaching us. Thank you!


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi, Cynthia. Thanks for sharing such an interesting, insightful and kind comment! I appreciate your visit very much.


poetryman6969 profile image

poetryman6969 2 years ago

Not a pleasant subject but thanks for spreading the news.


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi, poetryman6969. No, the topic of head lice isn't pleasant for people who are infested with them! Thanks for the comment,


vespawoolf profile image

vespawoolf 2 years ago from Peru, South America

I´m always fascinated with natural treatments. I had no idea the components in these flowers interfere with the life cycle of a louse. I also think wet combing is a good option for ridding a child of nits. Very interesting!


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Thanks for the comment, vespawoolf. I appreciate your visit.


aviannovice profile image

aviannovice 2 years ago from Stillwater, OK

This was very good. Mums and other natural plants are wonderful in an assortment of treatments. I recall having a naturally made cough medicine that made me well in three days, as opposed to a standard cough medicine that too more than twice as long. Let'd hear it for holistic medicine!


AliciaC profile image

AliciaC 2 years ago from British Columbia, Canada Author

Hi, Deb. Yes, holistic medicine can be useful. Studying medicines in plants is an interesting topic. Thanks for commenting.


ologsinquito profile image

ologsinquito 23 months ago from USA

I feel so fortunate my children never picked these up. What a nuisance. Great article. Voted up and shared.


AliciaC profile image

AliciaC 23 months ago from British Columbia, Canada Author

Thank you very much for the comment and the share, ologsinquito. I appreciate your vote as well.


pstraubie48 profile image

pstraubie48 23 months ago from sunny Florida

I had no idea. When I was still a teacher of precious children, we had head check every Friday and the dolls who had lice went home till the problem was taken care of.

I had no idea that there were these sources to help treat an outbreak.

Angels are on the way to you this afternoon. ps


AliciaC profile image

AliciaC 23 months ago from British Columbia, Canada Author

Thank you very much for sharing your experience, pstraubie. I appreciate your comment and the angels a great deal!


CassandraCae profile image

CassandraCae 23 months ago from Ohio

I had lice when I was a child resistant to everything I put on my head. It was a nightmare. Finally I had to sleep with my head drenched in olive oil and wash out the little dead lice every morning. That and wet combing got me through it. It took like a week to kill the live ones and another week to get rid of all the nits but my mom and I finally got rid of the darn things. It was a nightmare I wouldn't wish on my enemy.


AliciaC profile image

AliciaC 23 months ago from British Columbia, Canada Author

Thanks for sharing your experience, Cassandra. It sounds like it was very unpleasant! Head lice can be a big nuisance. I hope a better way to treat them is discovered.


Rhonda Lytle profile image

Rhonda Lytle 23 months ago from Deep in the heart of Dixie

I had a high school student with really long hair, past her behind. She got them from some life skills students she was volunteering to work with. I'll never forget her crying. She was so upset. I got the treatment stuff at lunch and we did it after school. She lived on her own and had no family to help. After a few rounds of this, we still had not gotten rid of them and folks were calling for this poor girl to shave her head. While I hated she did it, dying her hair actually killed them all, the first time. My gorgeous blonde student went gothic black overnight but was lice free.


AliciaC profile image

AliciaC 23 months ago from British Columbia, Canada Author

What an interesting solution to the head lice problem! Thanks for sharing it, Rhonda. It sounds like it was a horrible situation for your student, but at least she found a way to get rid of the lice.


PegCole17 profile image

PegCole17 21 months ago from Dallas, Texas

This really creepy creature is quite durable. The fact that the natural treatment is losing effectiveness is not good. Those photos are incredible. Yikes. No wonder they cause intense itching.

We learned about head lice in cosmetology training but not to this extent. Very interesting. By law a hair stylist must discontinue any type of service once head lice are discovered even if a hair cut is half finished.


AliciaC profile image

AliciaC 21 months ago from British Columbia, Canada Author

Thanks for the comment and for sharing the interesting information, Peg. I pity a person who discovers that they have head lice at a hairdresser and also has to leave with an incomplete hair cut!

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