Headlice & Nits

Headlice & Nits

Headlice are not new. Headlice and the eggs (nits) have been with us for centuries. Egyptian mummies over 3000 years old have been found with the remains of headlice. It is only recently that the western world has been relatively free of headlice. No one to date has found a sure-fire way of totally eradicating headlice in a community. There may be ‘miracle cures’ offered but few live up to the claims.

Headlice are a common problem throughout the world. Schools do not give people headlice; people bring headlice to schools. Headlice are also brought to churches, supermarkets, sports fields and homes by people. A population is likely to host headlice most of the time. Infestation levels fluctuate for no apparent reason and sometimes headlice appear to be epidemic while at other times they appear to be absent.

Controlling headlice requires people in a community as a whole to act.


Headlice can jump or swim from person to person.


Headlice have legs designed for climbing so need to be able to crawl from person to person in close proximity. Headlice cannot swim.


Only dirty people have headlice.


Headlice feed on blood, not dirt. Anyone can host headlice.


People with dark-coloured hair get headlice more than other people.


It is easier to see the yellow-white nits in dark hair so darkhaired people are possibly able to manage the problem more easily. People with light-coloured hair may find it is easier to manage the brown headlice. Headlice like hosts with hair of any colour.


Headlice prefer certain blood types.


Headlice like to feed on any blood.


Children get headlice from classroom carpets or animals.


Headlice only live on human heads.


Schools with policies on headlice don’t have children with headlice.


A policy is not a magic protection but a well-thought-out policy does help a school manage the problem. However, a policy no one follows is no help at all.

Some facts

What to look for: Headlice are small insects approximately 2 to 4 mm long and about 1mm wide. They have six legs with claws and are usually a light or dark brown colour.

Eggs (nits) are small and hard like a grain of salt and are yellow-white in colour. Eggs are usually found on the hair very close to the scalp. Those found further from the scalp than one to one and half centimetres from the scalp are probably dead or hatched.

Sometimes a person with headlice or eggs might feel itchy, but not always.

Checking for headlice or eggs

Check weekly using bright light and by parting the hair. Check the scalp, especially at the front, nape of the neck, behind the ears and at the base of a pony tail or plaits.

Small red dots behind the ears and on the nape of the neck may be headlice bites. Eggs are usually easier to see than headlice. Don’t be confused by dandruff that is flaky and easily removed. Eggs will feel sandy or gritty when fingers are run through the hair.


Headlice crawl from head to head. Because young children are often in close proximity to one another in play or classwork, or in close proximity to family adults at home, headlice have opportunities to move from one head to another. It is impossible to know the origin of an outbreak.

A less likely method of transmission is through the sharing of things like combs, hairbrushes, hats, and other things that touch the head and hair.

Because headlice need food, humidity and warmth to survive it is unlikely they will be found alive on car seats, curtains or carpets.

Adolescents and adults tend to spend little time in close proximity to others so transmission of headlice amongst older people is less likely than amongst the young.

Temperature and Humidity

Headlice and the eggs (nits) enjoy warmth. Between 28 and 32 degrees centigrade makes the human head an ideal place for headlice to live. Humidity needs to be about 75% in order for eggs (nits) to hatch.


Blood is the food of headlice. Headlice need something to cling to and to lay their eggs on. Headlice find a head of hair a most suitable place to live.

Hosting headlice

Headlice do not cause disease. They may cause an uncomfortable itching. At worst, a child with headlice may scratch excessively and break the scalp possibly allowing infection in. An infestation of headlice should be detected and dealt with long before it becomes either highly visible or irritating.

Preventing headlice

  • Avoid head to head contact.
  • Don’t share brushes, combs, hats and other items that come into contact with hair.
  • Discourage children from playing with each others’ hair.
  • Tie long hair back or plait it.
  • Brush hair regularly.
  • Check the hair of everyone in the family at least once a week.
  • Take action if a child is scratching unusually – check their head carefully.


Ideally, once headlice are detected in a school, the whole school community should take action at the same time and over a period of weeks. One untreated head in a community can ensure an outbreak continues for months.

Treatment must be thorough, regular and carried out over a period of weeks by everyone. Even so, such treatment will not prevent a re-infestation originating from another community. Keeping headlice under control requires constant vigilance.

Effective treatment can be cheap. A combination of methods is likely to be most successful.

Dry combing

This method is for removal of headlice and eggs.

  • Use a metal fine-toothed comb. The National Pediculosis Association in the United States recommends combs that have individually tooled rounded teeth that are evenly spaced and set in a plastic handle.
  • Fingernails can effectively remove eggs.
  • Individual strands of hair can be cut to remove difficult eggs.
  • Some combs will extract adult headlice only and leave the eggs; the closer together the teeth of the comb are, the more successful combing will be.

Wet combing

This method, using any kind of hair conditioner, is for detection and removal of headlice and eggs. It is recommended that this treatment be repeated on alternate days for three weeks. The idea is to smother the headlice with conditioner, preventing them moving away, and to allow manual removal. Do not use conditioner within a day of using a chemical treatment; it will make the chemical treatment ineffective.

  • Apply enough conditioner (much more than usual) on dry hair to thoroughly cover the whole scalp and all the hair from the roots to the tips.
  • Keep the conditioner in the hair. Conditioner stuns the insects for about 20 minutes.
  • Comb the hair straight and get knots out with an ordinary comb.
  • Use a fine-toothed comb to systematically comb the hair. Comb the full length of each hair.
  • Wipe the comb with a clean tissue after each stroke of the comb.
  • After thorough combing and inspection, wash the conditioner out.

Electric combs

Electric battery operated combs are available to be used on dry hair. These are claimed to stun or kill the headlice so they let go of the hair and can be combed out. Clean the teeth after each stroke of the comb. Electric combs should be used on alternate days for two or three weeks to break the breeding cycle. People with epilepsy, heart disease or pacemakers should not use them.


Short hair is easier to comb, requires less time to treat and makes detection easier. It should not be necessary to shave heads. Hairdressers may refuse to cut infested hair.


The use of any chemical in or on the body carries risk. Some older treatments for headlice are no longer available because of the risk they posed. The chemicals used are insecticides and should be used with care and strictly as directed by the manufacturer. Chemicals are expensive.

There are three chemicals that are most commonly used:

Pyrethrins – derived from chrysanthemum flowers, these attack the insects’ nervous system but break down in sunlight. These are usually combined with piperonyl butoxide for more effectiveness.

Pyrethroids – synthetic pyrethrins that are more stable in sunlight.

Maldeson – an organophosphate insecticide that attacks the insects’ nervous system.

  • Apply the treatment strictly in accordance with the manufacturer’s instructions.
  • Treat those members of the household who appear to be hosting headlice. Do not treat babies with chemicals.
  • Do not wash the hair or use conditioners for at least 24 hours after treating. Treatments are designed to coat the hair shaft and should be allowed to remain. Do not wash chemicals off.
  • Do not use hairdryers on treated hair. The heat may break down the active chemical.
  • Comb the hair carefully to remove as many dead or live headlice and eggs as possible.
  • Repeat the treatment after seven to ten days.
  • Check all members of the household daily for a period of three weeks.

Herbal remedies

Several herbal preparations are available, however the effectiveness of these is not clearly established. Most herbal remedies might be regarded as expensive conditioners that are no more effective than other conditioners. Some, such as tea tree oil, may be, volume for volume, more toxic to humans than chemical preparations. Olive oil, hair gel and mayonnaise may make combing easier.

What else can help?

Extra precautions may include washing all bedlinen and certainly pillowcases and towels in hot water (at least 60 degrees centigrade) and tumble drying for 20 minutes on high. Other items that have come in contact with heads should also be thoroughly cleaned. Soak hairbrushes and combs in hot water for at least ten minutes. Vacuuming carpets and rugs may also be helpful, if only to ensure that dead nits and lice are collected and not left to reappear on the heads or clothing of people in the household.

What can a school do?

The legal position: National Administration Guideline 1(iii) requires schools to report to parents on matters likely to prevent students from achieving. National Administration Guideline 5 requires schools to maintain a safe physical and emotional environment for students. Both of these guidelines mean a school must take some action in the event that it becomes apparent that children are attending school with headlice.

Section 19 of the Education Act 1989 enables the principal of a school to preclude a student who is not clean enough to keep attending school or may have a communicable disease. A communicable disease is defined by the Health Act 1956 and includes pediculosis (lice).

A child who is precluded under this section of the Education Act 1989 is neither stood-down nor suspended.

The Education Act 1989 prescribes what a principal and a board must do if a student is precluded.

The principal must make all reasonable efforts to tell:

  • the board;
  • either the student (if the student is over 20) or the student’s parents (in all other cases); and
  • the Medical Officer of Health,

that the student has been precluded and why.

The board must have the matter looked into and will either cancel the preclusion or confirm the preclusion until the principal is satisfied that the student is clean or well enough to go back to school.

Prolonged preclusion of a child would be an unusual and drastic action to take. To preclude one child and not others who may be infested would possibly breach a child’s rights under the Human Rights Act. Preclusion would also require some form of inspection that would be difficult to carry out within the law and would be likely to lead to unreliable evidence being gathered.

It is not the role of the school to conduct mass head inspections, treat children or give expert advice in this area. Inspection, detection and treatment are the role of the parent.

So what should a school do?

  • Review school policies to ensure that the way the school will react to headlice will be effective in limiting infestation and will not lead to other difficulties for children, such as prolonged absence from school, infestation of others or bullying.
  • Include teaching about body care and cleanliness in the school health and physical education teaching plan.
  • Include teaching about insects and parasites in the science teaching plan.
  • Contact a Health Promoting Schools co-ordinator in the region and develop a school plan to raise school and community awareness and help prevent infestation before an outbreak occurs. Local contacts and other information can be found on the Health Promoting Schools website, www.hps.org.nz
  • Send periodic reminders to families about the need to check all family hair weekly and, if need be, to commence treatment immediately. Reminders sent home once each term will be more effective than waiting for a perceived crisis time.
  • Inform parents as soon as possible if their child is suspected of having headlice.
  • Inform parents of other children in close contact with an infested child that a case is suspected.
  • Reinforce the message that everyone in the school community should be checked and any infestation treated immediately and completely until clear, then rechecked regularly.
  • Seek advice from health professionals on the latest methods of treatment.
  • Provide parents with up to date prevention and treatment information. The Public Health Nurse can assist with parent and child education.

Be sensitive to the emotional safety of all children who are suspected of being infested and of the other children in the class or school (National Administration Guideline 5).

Be aware that there is likely to be a strong emotional reaction from parents. Remain calm and matter of fact when dealing with the issue.

What should a class teacher do?

  • Begin any discussion about headlice and nits early in the year before there has been any infestation. Include regular reminders throughout the year as might be given about matters such as cleaning teeth and finger nails, washing hands and other general self-care.
  • Understand that clumsy handling of a suspected infestation could not only upset a child but could also result in social repercussions including bullying of the child by others.
  • React to a suspected infestation in a calm, discrete and matter of fact professional manner.
  • Sensitively ensure the child suspected of infestation is removed and kept apart from close contact with others in the class. There is no need to isolate the child.
  • Contact the parents to collect the child to begin treatment as soon as possible that day. This is important for the comfort and emotional well being of the child and to ensure control of the infestation.
  • Ensure that the parent has the information needed to effectively deal with the problem. The school Health Nurse may wish to be involved.
  • Be alert for further infestation among class members.
  • Ensure that the school informs all parents of a suspected outbreak.
  • Be aware that any close head inspection beyond a cursory visual inspection requires parental consent and carries professional risk. Any full inspection and treatment is the responsibility of the parent.


Headlice are a community problem that needs to be controlled by the whole community. If a family fails to check and treat a child’s head the work done by others to control the problem is likely to be wasted. It is a parent’s responsibility to check and treat their children.

There are a number of actions a school can take to help ensure that any outbreaks are detected and treated early.

Teachers and schools should deal with infestations in a sympathetic and professional manner.

There are a variety of treatments available to families ranging in cost from very cheap to very expensive. How much a treatment costs is no measure of its effectiveness. There is evidence to suggest that systematic and regular physical treatment can markedly reduce the risk and severity of infestation.

Any family can host headlice. All families can detect and treat an infestation.

Parent information letter – sample:

School logo / name of school

Dear Parents / Caregivers

Headlice may be present amongst children in your child’s class. These insects are a nuisance and can be controlled or eradicated by families. Headlice crawl from head to head and may be passed on through shared objects such as hairbrushes and hats.

It is recommended that you check all members of your household carefully. Anyone can host headlice. Cleanliness is not a factor in whether headlice are present or not.

What to look for

  • Small light or dark brown insects without wings.
  • Tiny whitish eggs (nits) like grains of salt attached to hair shafts.
  • There may be unusual itching on the head or neck.
  • Small red marks on the neck or behind the ears (headlice bites).

What to do

  • Check all members of the household daily at the same time for at least three weeks.
  • Treat anyone who is hosting headlice. Effective treatment need not be chemical or expensive.
  • Please advise the school if you find headlice and confirm that treatment has begun.
  • Be prepared to continue treatment for about three weeks depending on the method chosen. Three weeks is the length of the headlouse breeding cycle; you need to break the cycle or infestation will continue.
  • After each treatment, comb the hair with a fine toothed comb.
  • Extra precautions may include washing all bedlinen, pillowcases and towels in hot water and tumble drying for 20 minutes on high. Other items that have come in contact with heads should also be thoroughly cleaned.
  • Soak hairbrushes and combs in hot water for at least ten minutes.
  • Vacuuming carpets and rugs may be helpful.
  • Repeat treatment 7 to 10 days after initial treatment.

Treating the hair is no guarantee that the problem has been eradicated. Success is more likely if treatment is thorough, checking is daily for at least three weeks and children are reminded to avoid head to head contact with others.

What not to do

  • Do not use shampoo, conditioner or a hair drier on hair within 24 hours of using a chemical treatment. Each of these can make the treatment less effective or cause it to fail.
  • Do not use ordinary insecticides, pet shampoo or flammable petroleum products.
  • Do not use chemical products if the person applying the treatment or the person being treated is pregnant.

Thank you for your co-operation. Please contact the school for further information.