2. Head Lice Public Health

3. Agenda Objectives What are head lice Transmission Detection Treatment
Retreatment
Prevention and control
Responsibility
Lice in School
References

4. Objectives To increase the Public Health Nurse knowledge in order
to provide clear, accurate, up to date information to the
community about head lice.

5. Problem of Society
Head lice infestations remain an annoying communicable problem, particularly in school-age children in Canada and elsewhere.
All socioeconomic groups are affected.
Head lice infestations are common in many parts of the world.
Getting head lice is not related to cleanliness of the person or his or her environment.

6. Problem of Society (...) Head lice are not known to transmit disease
They rarely cause physical symptoms other than itching of the scalp.
Adverse health effects mainly derive not from lice themselves, but from the human perception of them.
Head louse infection is more a societal than an infectious disease problem
Reference:
Head Lice: Evidence-Based Guidelines Based on the Stafford Report 2012 Update, p.4
Excessive public and professional reactions lead to an inflated perception of prevalence, to unnecessary, inappropriate or ineffective action, and to a great deal of unwarranted anxiety and distress. These actions and reactions in themselves cause problems, especially from the misuse and overuse of treatments.
American Pediatrics - Itching can develop in a sensitized individual.

7. What are Head Lice?
Parasitic insect that can be found on the head, eyebrows, and eyelashes of people.
They feed on human blood
They live close to the human scalp.
They move by crawling; they cannot hop or fly
Reference:
CDC Head Lice General Information
Head lice and egg/nits are found almost exclusively on the scalp, particularly around and behind the ears and near the neckline at the back of the head.
Head lice hold tightly to hair. Head lice nits are cemented firmly to the hair shaft and can be difficult to remove even after the nymphs hatch and empty casings remain

8. What do Head Lice Look Like?
Reference:
CDC – Head Lice – General Information

9. The life cycle Head lice have three stages:
the egg (also called a nit),
the nymph,
And the adult.
Reference:
CDC
Head lice survive less than one or two days if they fall off the scalp and cannot feed.
Head lice eggs (nits) cannot hatch and usually die within a week if they do not remain under ideal conditions of heat and humidity similar to those found close to the human scalp.
Therefore, because a nit must incubate under conditions equivalent to those found near the human scalp, it is very unlikely to hatch away from the head.
In addition, if the egg were to hatch, the newly emerged nymph would die within several hours if it did not feed on human blood.

10. Illustration of Egg on a Hair Shaft and Adult Louse
Brightfield, x70.
Brightfield, x30.

11. The Egg/Nit
They are laid by the adult female at the base of the hair shaft close to the scalp.
They are oval-shaped, very small and hard to see
They cling to the hair shaft, along the neckline and behind the ears.
Head lice nits usually take about 8-9 days to hatch.
Eggs that are likely to hatch are usually found no more than ¼ inch (6 mm) from the base of the hair shaft.
They are oval-shaped, very small (about the size of a knot in thread) and hard to see
Reference: CDC Head Lice – General Information
This is difficult to distinguish with the naked eye.
Nits are often confused with dandruff, scabs or hair spray droplets.
Nits located further than ¼ inch from the base of hair shaft may very well be already hatched, non-viable nits or empty nits or casings.
Nits often appear yellow or white although live nits sometimes appear to be the same color as the hair of the infested person.
These tiny eggs are firmly attached to the base of the hair shaft within approximately 4 mm of the scalp with a glue-like substance produced by the louse.
They are difficult to remove even after the nymphs hatch and empty casings remain.
While eggs can survive away from the host for up to 3 days, they require the higher temperature found near the scalp to hatch.

12. The Nymph Baby lice that hatches from the nit (egg).
Looks like an adult lice, but is smaller.
It is about the size of a pinhead.
They must feed on blood to live.
Nymphs mature into adults about 9-12 days after hatching from the nit.
References:
CDC Head Lice – General Information
The egg hatches to release a nymph.
The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft

13. Adult Louse The adult louse is roughly 2-3 mm long
(about the size of a sesame seed).
It has 6 legs (each with claws).
Is tan to grayish-white.
Once mature, they can live up to 30 days on a person’s head.
They need to feed on blood to live.
Without blood meals, the louse will die within 1 to 2 days off the host.
Reference:
CDC Head Lice – General Information
In persons with dark hair, the adult louse will appear darker.
Females are usually larger than males and can lay up to 8 eggs/nits per day.
Canadian Paediatric Society
Head lice stay close to the scalp for food, warmth, shelter and moisture. They are hard to see. Nymphs and adult head lice can survive for up to three days away from the human host. While eggs can survive away from the host for up to three days, they require the higher temperature found near the scalp to hatch.

14. Transmission
The most common way to get head lice is by head-to-head contact with a person who already has head lice.
Such contact can be common among children during play at:
school,
home and
elsewhere (e.g., sports activities, playgrounds, camp, and slumber parties).
Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.
Reference:
CDC Head Lice – General Information
Head lice are spread by direct contact with the hair of an infested person.
Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk

15. Uncommonly, transmission can occur by:
Wearing clothing, such as hats, scarves, coats, sports uniforms or hair ribbons worn by an infested person;
Using infested combs, brushes or towels;
Lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with an infested person.
Dogs, cats, and other pets do not play a role in the spread of head lice.
References:
CDC Head Lice Epidemiology & Risks Factors:
Although uncommon, head lice can be spread by sharing clothing or belongings. This happens when lice crawl, or nits attached to shed hair hatch, and get on the shared clothing or belongings. Some studies suggest that girls get head lice more often than boys, probably due to more frequent head-to-head contact.
American Pediatrics:
Lice found on combs are likely to be injured or dead, and a healthy louse is not likely to leave a healthy head unless there is a heavy infestation. This is further illustrated by 2 studies from Australia. In 1 study, examination of carpets on 118 classroom floors found no lice despite more than live lice found on the heads of 466 children using these classrooms.
In a second study, live lice were found on only 4% of pillowcases used by infested volunteers. Thus, the major focus of control activities should be to reduce the number of lice on the head and to lessen the risks of head-to-head contact.

16. Detection
The detection of head lice infestation is best made by finding a live nymph or adult louse on the scalp or hair of a person.
Close examination of the hair and scalp is necessary to determine head lice infestation.
Using a fine-toothed comb may be helpful to find live lice.
Because nymphs and adult lice are very small, move quickly, and avoid light, they can be difficult to find.
If crawling lice are not seen, finding nits firmly attached within a ¼ inch of base of the hair shafts strongly suggests, but does not confirm, that a person is infested and should be treated.
Reference:
CDC – General Information
Nits frequently are seen on hair behind the ears and near the back of the neck. Head lice and nits can be visible with the naked eye, although use of a magnifying lens may be necessary to find crawling lice or to identify a developing nymph inside a viable nit.
If no live nymphs or adult lice are seen, and the only nits found are more than ¼-inch from the scalp, the infestation is probably old and no longer active and does not need to be treated.
The diagnosis of a head lice infestation is best made by finding a live nymph or adult louse on the scalp or hair of a person. Because nymphs and adult lice are very small, move quickly, and avoid light, they can be difficult to find. Use of a magnifying lens and a fine-toothed comb may be helpful to find live lice.
Document Stafford report 2012, page 7
The only reliable method of diagnosing current, active infection with head lice is by detection combing. If detection combing is not used as the diagnostic criterion, a misdiagnosis may be made.
International Guidelines for effective control of Head Louse infestation p
There are several methods for detecting head lice. Most examinations are done by direct visual examination by hand or with the help of a screening stick and the diagnosis of louse infestation is mainly based on the presence of nits. Combing dry hair with a louse comb is 4 times more effective in the diagnosis of a louse infestation and twice as fast as examination by hand. The distinction between living lice and nits is especially important as living lice indicate active infestation while nits may only indicate past, nonactive infestation.
A diagnosis of head louse infection cannot be made with certainty (no matter how many nits are present, how many reported cases there are in school, how bad the itch is or however dirty the pillows are) unless a living, moving louse is found.

17. Detection http://www.youtube.com/watch?v=EMqj88S8lMg
how to check your child for head lice. (She is looking for nits – dividing hair)
how to check for head lice with nurse consultant Christine Brown
(Bug Kit)
Publication: Lice Lice Lice…all there is to know about head lice (Santé Québec)
How?
• Place the child’s head under a good light: head lice flee from light and you can see them moving (a magnifying glass can help).
• Wet the hair, then comb it with the nit comb. Conditioner makes louse hunting easier. Conditioner is not recommended when you’re using Kwellada-P® 1% or Nix® 1% because it reduces the effectiveness of the treatment
• Look for lice and nits, especially behind the ears and near the back of the neck.
• Separate the hair into tufts the width of the comb. In the case of very long hair, the tufts should be about 2 cm in width.
• Comb the hair from scalp to tip with a nit comb (fine tooth comb).
• Examine the hair section by section, from one side to the other and from the forehead back to the nape of
the neck.
• Look for lice or nits on the comb each time you run it through the hair.
Wash your hands after each examination.

18. Treatment (General Guidelines)
Treatment for head lice is recommended for persons diagnosed with an active infestation (nymph, Live Lice)
All household members and other close contacts should be checked
All infested persons (household members and close contacts) and their bedmates should be treated at the same time.
References:
CDC – Treatment General Guidelines
Stafford document page 5
A day or two after using the lotion, you sometimes find little lice still there. These have hatched out of the eggs since you put the lotion on and will be killed if you put the lotion on again after seven days.
Stafford document page 22
When living, moving lice are found, they can almost always be cleared by using the right lotion. This will only work if enough of it is used, if it is put on in the right way, and if any other family members or close friends who have lice are properly treated at the same time.
Don’t treat unless you are sure that you have found a living, moving louse.
Stafford document page 26
When you have got rid of the lice, you may still itch for two or three weeks. This doesn’t mean you still have lice. Check the head carefully. Remember, you don’t have head lice if you can’t find a living, moving louse.

19. Topical Treatment Steps of Head Lice Infestations
Treat the infested person (s):
Apply lice medicine, also called pediculicide, according to the instructions contained in the box or printed on the label.
Pay special attention to instructions on the label or in the box regarding how long the medication should be left on the hair and how it should be washed out.
Reference:
CDC - Treatment
Requires using an over-the-counter (OTC) or prescription medication.
Follow these treatment steps:
Before applying treatment, it may be helpful to remove clothing that can become wet or stained during treatment.
If the infested person has very long hair (longer than shoulder length), it may be necessary to use a second bottle.

20. Topical Treatment (Warning)
Do not use a combination shampoo/conditioner or conditioner before using lice medicine.
Do not re-wash the hair for 48 hours after the lice medicine is removed.
Have the infested person put on clean clothing after treatment.
Comb dead and any remaining live lice out of the hair using a fine-toothed nit comb.
Many flea combs made for cats and dogs are also effective.
If a few live lice are still found 8-12 hours after treatment, but are moving more slowly than before, do not retreat. The medicine may take longer to kill all the lice.
Reference:
CDC Treatment
If, after 8-12 hours of treatment, no dead lice are found and lice seem as active as before, the medicine may not be working.
Do not retreat until speaking with your health care provider; a different lice medicine (pediculicide) may be necessary.
If your health care provider recommends a different pediculicide, carefully follow the treatment instructions contained in the box or printed on the label.

21. Topical Treatment (Warning)
Nit (head lice egg) combs, often found in lice medicine packages, should be used to comb nits and lice from the hair shaft.
After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2-3 days may decrease the chance of self re-infestation.
Continue to check for 2-3 weeks to be sure all lice and nits are gone.

22. When Treating Head Lice
Do not use extra amounts of any lice medication unless instructed
to do so by your physician and pharmacist.
Do not treat an infested person more than 2-3 times with the same
medication if it does not seem to be working.
Do not use different head lice drugs at the same time unless
instructed to do so by your physician and pharmacist.
This may be caused by using the medicine incorrectly or by resistance to the medicine. Always seek the advice of your health care provider if this should happen. He/she may recommend an alternative medication.
Reference:
CDC Treatment General Guidelines
The drugs used to treat lice are insecticides and can be dangerous if they are misused or overused.

23. Supplemental Measures
Head lice do not survive long if they
fall off a person and cannot feed.
Follow these steps to help avoid re-infestation
Machine wash and dry clothing, bed linens, and other items that the infested person wore or used during the 2 days before treatment using the hot water (60 degree C /130°F) laundry cycle and the high heat drying cycle.
Clothing and items that are not washable can be dry-cleaned OR sealed in a plastic bag and stored for 2 weeks.
You don't need to spend a lot of time or money on house cleaning activities.
References:
CDC (Treatment – General guidelines)

24. Supplemental Measures
Soak combs and brushes in hot water (at least 130°F) for 5-10 minutes.
Vacuum the floor and furniture, particularly where the infested person sat or lay.
Do not use fumigant sprays; they can be toxic if inhaled or absorbed through the skin.
However, the risk of getting infested by a louse that has fallen onto a rug or carpet or furniture is very small. Head lice survive less than 1-2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the human scalp.
Reference:Head lice survive less than 1-2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the human scalp.
CDC (Treatment – General Guidelines)
The risk of getting infested by a louse that has fallen onto a carpet or furniture is very small.
American Pediatrics
Although head lice are able to survive for prolonged periods in chlorinated water, it is unlikely that there is a significant risk of transmission in swimming pools. One study revealed that submerged head lice became immobile and remained in place on 4 people infested with head lice after 30 minutes of swimming.
Viable nits are unlikely to incubate and hatch at room temperatures; if they did, the nymphs would need to find a source of blood for feeding within hours of hatching.
Although it is rarely necessary, items that cannot be washed can be bagged in plastic for 2 weeks, a time when any nits that may have survived would have hatched and nymphs would die without a source for feeding. Herculean cleaning measures are not beneficial.

25. Is it necessary to remove all the nits?No
The two treatments 9 days apart are designed to eliminate all lice, and any lice that may hatch from eggs that were laid after the first treatment
Removal of nits after treatment with a pediculicide may be done for aesthetic reasons or to reduce diagnostic confusion and the chance of unnecessary retreatment.
Because pediculicides are not 100% ovicidal (i.e. do not kill all the egg stages), some experts recommend the manual removal of nits that are attached less than 1 cm of the base of the hair shaft.
Reference
CDC
Many nits are more than ¼ inch from the scalp. Such nits are usually not viable and very unlikely to hatch to become crawling lice, or may in fact be empty shells, also known as casings. Nits are cemented to hair shafts and are very unlikely to be transferred successfully to other people.

26. Retreatment
To be most effective, retreatment generally is recommended for most prescription and non-prescription (over-the-counter) drugs on day 9 in order to kill any surviving hatched lice before they produce new eggs.
Reference:
CDC Treatment
If you have nits it doesn’t always mean that you have head lice. When you have got rid of all the lice, the nits will stay stuck to the hair until it grows out.
You only have head lice if you can find a living, moving louse (not a nit) on the scalp. Page 24 Stafford document

27. Prevention and Control
It is probably impossible to prevent all head lice infestations since young children come into head-to-head contact with each other frequently.
It is prudent for children to be taught not to share personal items such as combs, brushes, and hats. However, no one should refuse to wear protective headgear because of fear of head lice.
Adults should be aware of the signs and symptoms of head lice infestation
Infested children should be treated promptly to minimize spread to others.
Reference:
American Pediatrics 27

28. Responsibility of the Control of Head Lice
The primary responsibility for the identification, treatment and prevention of head lice in a family has to lie with the parents, if only for reasons of practicality.
Parents, however, cannot be expected to diagnose current infection, or to distinguish it from successfully treated previous infection or other conditions, if they are not adequately instructed and supported by professionals.
Reference:
Stafford document 2012, page 4
Professionals: primary care team, pharmacists, school health services, teachers, (Stafford document 2012, p )

29. What Families can do
Make sure that all family members know about good hair care.
The only way to control head lice that works is for the family to check their own heads regularly.
Only if you are sure you have found living, moving head lice in your family or household, tell your relatives and close friends so that they can check their own heads.
Make sure that all family members know about good hair care, including regular, thorough combing. Treat any of your household your are sure have lice at the same time.
Reference:
Document Stafford, page 26
All the family means everyone (adults as well as children) in the same household.

30. “Re-infection” or “Treatment failure”
Many cases of “re-infection” are due to one of the following:
Imaginary lice
Inadequate or inappropriate treatment
Misdiagnosis, for example itch or nits still present after successful eradication of living lice
The finding of young lice that have not been killed while in the egg after the first and before the second application of lotion.
True re-infection is usually from a close contact in the community.
References:
Document Stafford page 12
Although true resistance does occur, other causes of apparent “resistance” may be more likely to be due to ovicidal failure, misdiagnosis, faulty treatment technique or possibly failure to eradicate imaginary lice (D).
The often arduous process of determining whether there was a true active infection and whether “treatment failure” was due to misdiagnosis or inappropriate/inadequate treatment is, therefore, necessary.
Document Stafford page 26
If children do really keep on having living lice, this is most likely to be due to not doing the treatment properly and not treating all those close contacts who have also been found to have lice. Remember, if infection really does keep on happening, it is almost always from a member of the family or a close friend. It is rarely from other children in the classroom, except from a “best friend”.
Where some carriers of lice are likely not to be aware that they are infected, others may have struggled for some time despite treatment.
Canadian Paediatrics Society Head lice infestation: A clinical update 2008
Resistance has been reported with pyrethrins, permethrin and lindane in a number of countries. The resistance in Canada are unknown because formal studies have not been performed. A number of other diagnoses should be ruled out before resistance is considered: misdiagnosis and overdiagnosis(diagnosis requires detection of live lice before treatment); poor compliance with instructions for proper application of the topical insecticide, lack of secondary application or reapplication too soon after first application and new infestation acquired after treatment.

31. Lice in School Exclusion not required
Recommend to parents to apply treatment on child and may return to school afterwards.
Nits may persist after treatment, but successful treatment should kill crawling lice.
Students diagnosed with live head lice do not need to be sent home early from school; they can go home at the end of the day, be treated, and return to class after appropriate treatment has begun. e:
Reference:CDC (Information for school)
Document International Guidelines for Head Louse Infestation, p. 412 Measures to be taken after the diagnosis at school
Children with lice or nits should be sent home at the end of the day with a letter to their parents suggesting that the child be examined and if necessary treated the same day. However, excluding children from school because of the presence of lice or nits is not recommended. Children should be allowed to return to school immediately after the first treatment session. Ideally, the school nurse could check for lice on the 10th day after the letter was sent and do follow-up inspections until the treatment is successful (ie: retreat on day 10 not day 7) the treatment is successful (ie, re-treat on day 10 not day 7).
Canadian Paediatrics (Head Lice A clinical update)
The American Academy of Pediatrics and the Public Health Medicine Environmental Group in the United Kingdom also discourage “no nit” school policies.

32. School Head Lice and Nit Policies
Exclusion from school due to the detection of the presence of « nits » does not have sound medical rationale and it is not recommended by the Canadian Pediatric Society.
Even the detection of active head lice should not lead to the exclusions of the affected child.
Treatment should be recommended and close head-to-head contact should be discouraged pending treatment.

33. School Head Lice and Nit Policies
"No-nit" policies that require a child to be free of nits before they can return to schools should be discontinued for the following reasons:
Such nits are usually not viable and may in fact be empty shells.
Very unlikely to be transferred successfully to other people.
The burden of unnecessary absenteeism far outweighs the risks associated with head lice.
Misdiagnosis of nits is very common.
Reference:
CDC (Head Lice - Information for Schools.
Nits may persist after treatment, but successful treatment should kill crawling lice.
Document : International guidelines for effective control of head lice infestations
The efficacy of the no-nit policy was questioned by different groups of scientists and by several agencies, including the American Academy of Pediatrics and the National Association of School Nurses (US).
In Australia, the National Health and Medical Research Council's Guidelines for Infectious Diseases warranting school exclusion have been recently amended to exclude head lice.
Furthermore, there are no convincing data that show enforced exclusion policies are effective in reducing the transmission of lice.
Therefore, the no-nit policy is unjust as it is based on misinformation rather than objective science and should be discontinued.

34. School Head Lice and Nits Policy
The presence of nits alone is not an accurate indicator of an active head louse infestation.
When the diagnosis of head louse infestation is based on the presence of nits, 1 to 2 out of 3 children are sent home for treatment without justification. Pediculicides will not eliminate nits.
If no living lice are detected using an accurate method of detection, the child should be considered negative for head louse infestation.
Treat only if presence of living lice.
Children who are infested with nits only should be examined, first on a few consecutive days and then one week later for living lice.
Since these children are usually at higher risk of a new infection than children that have not been infested in the last 2 to 5 months (ie, children without nits)
Reference:
Document: International guidelines for effective control of head lice infestations page
The No-nit policy, based on the persistence of empty egg cases, is not justified and does more harm than good; therefore, we recommend that it be immediately halted.

35. The Effects of the No-Nits Policy
Involves long hours of work.
Repeated treatments with pediculicides.
Absence from school for the child and possibly from work for at least one parent.
Negative effects on the parent-child relationship and also on child’s self-esteem.
It does not necessarily mean that the person is no longer infested with lice.
Especially when combing becomes painful and the parent and/or child become impatient.
The immediate expulsion of children from a camp, kindergarten, or school may cause significant damage to their self esteem and also upsets their parents
Reference:
Document: International guidelines for effective control of head lice infestations p

36. Remember
The gold standard for diagnosing head lice is finding a live louse on the head
The distinction between living lice and nits is especially important as living lice indicate active infestation while nits may only indicate past, non active infestation.
Two applications seven to 10 days apart is recommended when a case of active infestation is detected. 36

37. References Center for Disease Control and Prevention:
Stafford Report 2012 Update:
2007 Journal of Drugs in Dermatology:
American Academy of Pediatrics:
c788-4cf0-ac94-9c8ebee2e7fa
Canadian Paediatric Society: