Lice

Definition

Lice (called pediculosis in medical language) mainly affect children aged 3 to 12 years. In the last thirty years there has been a significant increase in the incidence of lice cases, becoming a problem that affects many individuals and families.
The main problem of parents in the treatment of lice comes from increased resistance in relation to products against lice, such as malation. Therefore, mechanical treatments (which do not use chemical agents) have been privileged.

For the treatment of lice, it is recommended that the patient check what symptoms and go to go to a pharmacy. In most cases it will not be necessary to consult a doctor. However, if lice affect pregnant women, infants, infants or young children, people with head injuries, with allergy to certain chemicals (which can be found in lice products), with asthma or epilepsy, a doctor should be sought for proper treatment of the case.

It is important to note that the person with lice does not share personal materials such as caps, hats, tiaras or other accessories worn on the head. It is also critical that the patient has his own comb and brush, as well as other accessories to use on the hair. If the child has lice, teachers and parents of other children should be warned, as lice are not a sign of poor hygiene, so do not be ashamed.

Size of lice Lice
are insects (parasites) that measure about 2-4 mm (size of a sesame seed), whose color is often close to the color of the hair. Lice cause itching and usually do not have serious health consequences.

You should know that lice cling to the hair and scalp, and females lay eggs called nits, these are white and about 1 mm in size. Lice have three pairs of paws with powerful claws.

Head lice Head
lice attach themselves to the hair and scalp with their legs. They like a lot of hair. Females (lice) lay eggs called nits, which are clear and about 1 mm in size. Lice have 3 pairs of powerful legs with claws.
Lice feed on the blood of the scalp and cause itching and red spots from the saliva injected during the bite. Blood intake is crucial for egg (nit) production
1I’m sorry, Several thousand species of lice have been described to date.2 .
Know that only live lice are capable of attaching themselves to hair. More information on head lice below under Causes

Hygiene
Head lice are not a sign of poor hygiene, on the contrary, they prefer a dry, fine, non-greasy and clean environment. Children’s hair often fulfills these conditions and is therefore the most affected.

Girls most affected
It is noted that head lice are more prevalent among girls. According to a study carried out in Iran in 2009 (published by the newspaper “Ca m’intéresse”, in February 2010), of the 850 students studied, girls had an infection rate of 13.5% against only 0.7% of the boys. It is the length of the hair that plays a determining role, there is no gender influence (eg hormone level) on head lice. Other theories say that girls are more affected by lice because they have closer contact with the head than boys.

Selfie and lice
The selfie trend, that is, taking a self-portrait with your smartphone to share on social media, can promote the transmission of lice. In fact, most of the time during a selfie many people tend to be right together, including head to head to appear in the image, which promotes the transmission of head lice.

Medical Consultation
A head lice infestation is not a disease and therefore does not require medical attention in most cases.

Epidemiology

– In the world, it is estimated that head lice infest more than 100 million people3.

– In the United States, a study carried out in 2016 showed that black (African-American) children were almost never affected by head lice. Researchers don’t know the scientific reason behind this difference with white or other ethnic group children. This study, conducted under the direction of Dr.Ellen Koch of the University of Pittsburgh, was published in the September/October 2016 issue of the scientific journalPediatric Dermatology .

Causes

Head lice are parasites or insects. They cause itchiness by feeding on blood from the scalp.

Learn more about lice

– A louse lives for 3 to 4 weeks. The reproductive cycle of the louse is about 21 days. In other words, at the age of 21 days, the louse starts laying nits and gives rise to about 10 nits a day. They hatch in 7 to 10 days. In total, a louse gives birth to about 100 other lice in its lifetime.

– Lice can survive between 1.5 and 2 days outside their community (hair). However, the vast majority of lice moves from one host (hair) to another. Lice found on clothing, for example, are mostly dead. That’s why the latest recommendations no longer suggest washing clothes and fabrics at 60°C, as this would be an unhelpful measure. Also read in Good advice.

– Lice like to breed in warm areas, such as the hair on the head, especially behind the ears (area to watch out for) or pubic hair (read our article: pubic lice).

Learn more about nits

– In the theoretical sense, nit represents the empty eggshell, but in French and US English it often refers to an egg that may be either viable (leading to a louse) or non-viable (theoretical definition of a nit).

A nit is white in color.

– It is estimated that the vast majority of nits (potentially viable eggs in this case) do not survive to adulthood, only 1 in 5 nits gives life to a louse.

That’s why some experts recommend not paying too much attention to the nits and focusing only on the lice and getting rid of them. The Canton of Vaud (Switzerland) recommends not to look for nits (in cases of nits, do not treat), only to look for lice. They recommend starting treatment only in cases of head lice.

– Nits (viable) are able to survive 6 days outside their environment.

Getting to know eggs and larvae better

– The eggs (or nymphs) are the structures in which the larvae are found (“babies” lice). It takes 7 days for a larva to hatch from an egg.

A larva takes an average of nine days to become an adult louse.

Head lice transmission occurs more frequently at home than at school, mainly because children have closer contacts at home, for example, playing with friends or siblings.

Symptoms

Lice, pediculosis in medical parlance, are usually located on the scalp (head lice). In young children head lice can sometimes develop on the eyebrows and eyelashes. Head lice are often located at the hairline and in warm areas of the scalp, such as behind the ears.

Itches and red spots
In general, lice cause severe itching (itching) that occurs a few weeks after being infected. Red spots from these itches can also often be observed, leading to infections. The red spots are actually small red dots that are signs of bites surrounded by a pink halo that is almost almost prominent. If the child is itchy, a scab may form. Sometimes the skin on the skull may turn a bluish-brown color (melanoderma), especially if left untreated. In some cases head lice may be present without itching. In fact, it is estimated that in 40% of cases there are no symptoms, so head lice can multiply even more easily. The 40% number is an estimate, we are not aware of any scientific study on this subject.

Lice and nits
It is very difficult to distinguish between lice (the lice are often the same color as the hair). On the contrary, it is easier to notice nits that are clear. Nits are usually attached to the hair near the root.
The nits remain attached to the hair, and they stay even after using a comb or shampoo, which helps to differentiate them from the film that comes off quickly with a touch of a comb.

To determine if you or your child has head lice, use a fine-tooth comb and good light.

Even with a single nit detected, treatment should be started, since the hatching nit can release many lice (7 to 10 days).

Note that to be sure the lice have been eliminated, you or your child should be examined by a specialist (doctor, nurse or pharmacist) who has more experience.

Treatments

There are 2 types of head lice treatment: chemical treatments and those with physical action.
Note:
Due to the increase in cases of resistance of lice to chemicals, the treatment of choice to fight lice are those of mechanical or physical action (see item 2).

1. Chemical treatments against head lice

There are lice gels or shampoos available from pharmacies. These products are based on deltamethrin, malathion, dermethrin, permethrin and lindane.

These products often need to be reapplied after a few days (usually 8-10 days). Ask the pharmacy for advice on drug names and exact dosage!

Deltamethrin
A particularly famous drug in Brazil is based on deltamethrin, an active substance in pyrethroids, a poison for insects such as lice. Despite its high safety and low toxicity for mammals, it is important that its use follows certain rules:
– avoid contact with cavities such as the nose, mouth and eyes
– do not ingest it under any circumstances
The advantage of chemical treatments lies in the ease of use (time of shorter application) than mechanical treatments.
However, the resistance of head lice to this type of chemical treatment can sometimes be strong (see also below), and chemical treatments are contraindicated in pregnant women and children under 4 years of age.

Permethrin
showed that permethrin has lost much of its effectiveness in recent years, mainly because of the increase in lice resistant to this molecule. Research conducted in the 2010s showed that the effectiveness rate of permethrin was around 25%, which is not much more than the efficiency of a placebo. When this product was put on the market several decades ago, the effectiveness rate was between 96% and 100%. This study published in
also advises against using lindane, which can be dangerous. However, this study recommends certain chemicals such as ivermectin, malathion and benzyl alcohol. Pediatric Dermatology As we saw in the case of permethrin, the resistance of lice to these chemicals is high (read more below).
However, this study recommends certain chemicals such as ivermectin, malathion and benzyl alcohol. As we have seen in the case of permethrin, the resistance of lice to these chemicals is high (read more below).

Furthermore, these treatments are contraindicated for pregnant women and children under 4 years of age (some sources refer to the age of 2 years).

Ivermectin
Topical (local) use of ivermectin appears to be an interesting therapeutic option and is mainly used in the United States. A study presented at an international conference on lice, theInternational Conference on Phthiraptera , in June 2018, showed greater effectiveness of ivermectin compared to other chemical treatments against lice.
As of 2020, ivermectin has been available over-the-counter (self-medication) in the United States for the treatment of pediculosis scalp in adults and children 6 months and older (Sklice® Lotion, as of November 2020 available in the US only). From 2012 to 2020, ivermectin was only available by prescription in the United States for external use against head lice. Oral ivermectin may eventually be used as a last resort for particularly resistant cases of scalp pediculosis.
4

2. Treatments with physical action (mechanical) against head lice

– Dimethicone
According to a 2014 article published in the leading independent French medical journal Prescrire, dimethicone is the first-choice treatment for head lice. This substance is effective in most cases and has few side effects.
Dimethicone is a silicone-like substance.
In July 2018, Swiss pharmaceutical head lice specialist Dr.Christina Ruob confirmed to Creapharma.ch (French version of this website) that according to the latest scientific research dimethicone was still thefirst line treatment to use against head lice .
Mechanism of action of dimethicone
This is a treatment that covers the louse with occlusive film that disturbs its water balance. Dimethitone especially obstructs the breathing or openings of the louse, leading to its death. Cases of resistance are minorities, since it is an action with a mechanism of physical and non-chemical action.
This is a treatment that covers the lice with an occlusive film that disturbs their water balance. Dimethicone especially obstructs the orifices or respiratory openings of the louse, leading to their death. Cases of resistance are minorities, since it is an action with a physical mechanism of action and not a chemical one.
However, the effect against nits is not very important.

Octane-1,2-diol Octane-1,2-diol mechanism of action
This molecule is an alcohol that attacks and involves lice. They dry from the inside and die.

– Coconut oil
There are also natural remedies based on coconut oil and aniseed that block the breathing of lice.

– Neem Oil
This oil would also have a physical action against head lice.

– Mineral oil
There are also treatments against lice based on mineral oils, such as paraffin oil (which often also contain 4% dimethicone and 96% paraffin oil sold in spray or shampoo with 70% paraffin oil and 25% Lumorol K 1000°). Oligodecene oil is a mineral oil also used against head lice.

Often these products need to be reapplied after a few days (usually 8-10 days), ask the pharmacy for advice on drug names and exact dosage!

Treatment advice
In general, it is recommended to apply these gels or shampoos close to the hair roots. Then massage well.

How to remove nits and lice?

Once you apply the treatment (chemical or physical) you must remove the residual nits with a special comb at least twice a week.
To remove nits, in particular, to avoid pain (the comb glides better with water), you can wash your hair with water or vinegar (1 tablespoon in a large bowl).
However, health authorities in certain regions, such as Switzerland, believe that we should not try to eliminate nits, that this is a waste of time, since only one in five nits reach adulthood, and rather eliminate only lice.

How to look for head lice?
To look for and find out if you have lice, do not wet your hair, cover your shoulders with a clean cloth (towel), apply 3 to 5 tablespoons of any post-shower combing cream to your hair (the aim is to separate the lice hair), do not rinse. Then untangle the hair with a normal comb, and pass the fine anti-lice comb strand by strand from the root to the end of the hair. Wipe the comb over the cloth (towel) with each pass and check for lice, and finally wash the hair. [Source: Sanimedia.ch, the official website of Canton de Vaud, Switzerland].
Lice control is required to be performed weekly after the second treatment (usually performed 8-10 days after the first treatment) for 1 month. If you cannot find lice, the treatment is complete, if not, a new course of treatment must be started. One should look for the presence of head lice in all family members.
These same authorities also noted that wet hair can facilitate the transmission of head lice. It is then advised not to wash the hair until an anti-lice product has been applied.

How to remove and kill lice with a comb?It is possible to remove lice, at least part of them, with a comb as we can see in the paragraph above. But to be sure to kill all the lice, also use the treatments mentioned above, ie chemical treatments and especially physical ones (eg dimethicone). The effectiveness of an anti-lice treatment using just a comb on wet hair (water conditioner) is 58%, according to Swiss head lice specialist Dr.Christina Ruob. To ensure maximum efficiency using only one lice comb, use the comb according to the procedure mentioned in the paragraph above, 2 times a day for 2 weeks. Since this method takes a long time and its effectiveness is not satisfactory, combing is mainly a complementary measure to conventional treatment (eg dimethicone) and, above all,
It is possible to remove lice, at least part of them, with a comb as we can see in the paragraph above. But to be sure to kill all lice, also use the treatments mentioned above, i.e. chemical and especially physical treatments (e.g. dimethicone). The effectiveness of an anti-lice treatment using only one comb in wet hair (water conditioner) is 58%, according to Swiss lice expert Dr. Christina Ruob. To ensure maximum efficiency using only a lice comb, pass the comb according to the procedure mentioned in the paragraph above, 2 times a day for 2 weeks. Since this method is long and with an unsatisfactory efficacy, the passage of the comb is mainly a complementary measure to conventional treatment (e.g. dimethitone) and above all, a way to control the presence or absence of lice.

Differences between nit combs and lice combs
According to Swiss pharmacist Dr.Christina Ruob, head lice specialist, interviewed by Create health.com.br in September 2017, there is a difference, at least theoretically, between anti-nit combs and anti-lice combs. The difference is especially in the distance between the teeth of the comb. But the head lice expert says that, in reality, combs sold on the market often have a distance of 200μm (0.2mm) between the teeth whether sold as anti-nits or anti-lice. In other words, a comb with a name of anti-nits can also be used as an anti-lice comb if the distance between the teeth is 200μm, the reverse is also true. These combs, if possible made of rigid plastic, must be able to retain lice, larvae, eggs and nits. Furthermore, this 200μm distance is ideal for both fine and thick hair.

Interesting observations about the treatment of head lice

– “Classic” or “chemical” treatments, like antibiotics, show resistance especially in the case of malathion (64% of cases of resistance to malathion in the head lice population, according to a French newspaper “Ca m’intéresse”, from February 2010). This makes the treatment of head lice increasingly difficult, so sometimes natural treatments or mechanical treatments (dimethicone or silicone) can lead to better results (see also our poll above).

In most treatments against lice (chemical and physical) it is important to repeat the application after one week of use (in some cases, it is necessary to repeat the third time after two weeks). It is estimated that in the first application there is, on average, 70% of lice death, which is not enough to eliminate the disease.

– Note that there are also preventive treatments (based on chemical molecules, coconut oil) for you or your child to use. Ask at the nearest pharmacy! However, some school doctors believe that no preventive treatment should be used as it is useless. But of course, it should be checked periodically if your child has head lice.

Medicinal plants against lice

Shampoos based on Willowbark can help eliminate and prevent head lice. It is more of a natural alternative treatment rather than a first-choice conventional treatment.

Apply two drops of lavenderessential oil to your hands, run your fingers through your hair, and repeat for several days in a row. This technique is effective in removing and preventing head lice.

other remedies

Use ofneutral henna for head lice prevention.

natural remedies

– oil against lice

As seen (in Treatments), coconut and neem oils can be used against head lice.

Tips & Prevention

– All people in contact with those who are infested with lice, must be controlled, in case of lice, use a treatment quickly. Use eventually preventive treatments.

– It is highly recommended to remove nits from wet hair with a special comb on days 1, 5, 9 and 13 (counted from the beginning of treatment), do not hesitate to go for a long time (30 minutes at a time). [Source: recommendations from the Robert-Koch Institute in Berlin, Germany].

– All fabrics (such as clothes, sheets, towels, plush toys,…) for children must be washed at a temperature above 60°C. If you can’t wash, place the fabrics in plastic bags and leave for 48 hours to starve the lice. A faster method is to place the plastic bag in the freezer for 24 hours, the lice will also die.
This tip, however, is still questioned by some specialists, because they believe that the lice found in clothes are already dead or dying, as we saw above, only live lice attach themselves to the hair.

– To remove nits you can use water with vinegar and then wash the hair containing nits with this water. Vinegar dissolves the nit shell and is very effective.

However, health authorities in certain regions, such as Switzerland, believe that we should not try to eliminate nits, that this is a waste of time, since only one in five nits reach adulthood, and rather eliminate only lice.

To look for and find out if you have lice, do not wet your hair, cover your shoulders with a clean cloth (towel), apply 3 to 5 tablespoons of any post-shower combing cream to your hair (the objective is to separate the lice from the hair), do not rinse. Then untangle the hair with a normal comb, and pass the fine anti-lice comb strand by strand from the root to the end of the hair. Wipe the comb over the cloth (towel) with each pass and check for lice, and finally wash the hair.

These same authorities also noted that wet hair can facilitate the transmission of head lice. It is then advised not to wash the hair until an anti-lice product has been applied.

– If your child has head lice, do not send them to school, notify the teacher and the school establishment so that they can take appropriate preventive measures.

– Soak combs, brushes and hair clips (including elastics) in warm soapy water (60°C) for 10 minutes. This tip is fundamental in the fight against head lice.

– Avoid contact with cups, bath towels and other accessories of a child with head lice.

– Do not try to dry your hair too hot, avoid drying your hair with a hairdryer.

– It is for advisable girls to tie their hair due to the length of the hair (for girls in particular, who are more affected than boys), this reduces the risk of contamination. This tip is fundamental in the fight against head lice.

– One of the most effective treatments, but also the most radical is to shave the hair, if possible this is the best measure! This solution probably applies much more to boys than girls.

– Shampoos made from willow bark can help with its preventive qualities.

– Head lice treatment can be long and complicated. As children often play together, it may take several weeks for the parents and doctor to remove the lice, as another child or adult may have lice and thus infect them again. It will therefore be necessary to identify possible sources of contamination. It is always a matter of contamination by human beings, as animals (including domestic ones) cannot transmit lice. In short, you should be patient and do an investigation if your child has head lice for several months, even when proper treatment is carried out.

– Beware of taking selfies (read above under Definition for more information), a possible cause of head lice transmission especially among teenagers.

– Finally, remember that after 10 days of treatment against lice, the complete control over the entire head must be repeated to see that there are in fact no more lice or nits.

Jeanne Kenney
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I’m a stylist trainer, a content creator, and an entrepreneur passion. Virgo sign and Pisces ascendant, I move easily between my dreams, the crazy world I want, and my feet on the ground to carry out my projects.

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