Head Lice: a report for Consultants in Communicable Disease Control (CCDCs)
This Statement should be read in conjunction with the Appendices which contain notes and guidance for involved professional groups (appendices 1-4, 8) and suggested key messages for public information (appendices 5-7). The latter are written in everyday non-technical language so as to be readily developed for distribution to the public, but should also be of value for training professional groups and for the development of protocols for them.
There has been insufficient research into the epidemiology of head louse infection for a high level of scientific certainty to be accorded to many aspects of the management of the problem. After careful consideration of diverse professional views, the authors, however, believe that a summary Statement will be of value to colleagues around the country and will encourage a consistent approach.
The Statement represents what the members of the Stafford Group believe to be a reasonable summary, based on the current state of scientific knowledge and on their own, and many colleagues’, professional experience.
The word "infection" is used throughout these documents to be consistent with the view that the term "infestation" has pejorative, stigmatic overtones and should be avoided in public information leaflets. See also Appendix 8: Glossary and Terminology.
The Statement is lengthy because it is intended to be an explanatory document, and to serve as the basis for the development of local policies and protocols. Because readers may selectively read sections applicable specifically to themselves, there has inevitably had to be some repetition in the document as a whole.
Recommendations have not been separated from the main text, since the authors believe it is important that readers understand the reasoning behind them.
Although head louse infection is an infectious disease many of the problems associated with the infection are due to society’s reaction to it rather than the organism itself.
The true prevalence of infection is unknown but is probably much lower than the public and professional perception.
Head lice are not a serious health problem in this country. They rarely, if ever, cause physical health problems other than itching of the scalp. Adverse health effects mainly derive not from the lice themselves, but from the human perception of them:
- 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.
Head louse infection is more a societal than an infectious disease problem
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 the following professionals.
(see "Appendix 1: notes and guidance for the primary care team".)
The primary professional responsibility for the diagnosis, management, and treatment of any individual for any disease lies with the general practitioner with whom the patient is registered, as also for advice and support on disease prevention. Historically, because of a misplaced emphasis on head louse infections in schools, the former system of head inspections, and the (now discontinued) distribution of large quantities of insecticidal lotions from Health Authority clinics, primary care teams did not traditionally involve themselves to any major degree. Nowadays, for primary care workers to refuse all responsibility for the management of individuals and families registered with them is as illogical as it would be to do so for measles, impetigo, threadworms or immunisation. General practitioners (or another member of the primary care staff) should therefore be knowledgeable and competent in the control of head lice, be able to teach parents the technique of detection combing, and be prepared to advise appropriate treatment. Treatment should never be advised unless the responsible officer is convinced by physical evidence that living lice are present on the head of at least one of the family.
(see "Appendix 2: notes and guidance for community pharmacists".)
Local pharmacists should inform themselves of local district policies and protocols and should adhere to them. Every opportunity should be taken to give accurate information to the public. Customers should be dissuaded from the inappropriate, repeated, or unnecessary use of insecticidal preparations. Pharmacists (or another member of their staff) should therefore be knowledgeable and competent in the control of head lice, be able to teach parents the technique of detection combing, and be prepared to advise appropriate treatment. Treatment should never be advised unless the responsible officer is convinced by physical evidence that living lice are present on at least one of the scalps of the family. Consideration should be given to the prescribing of insecticidal lotions by pharmacists.
(see "Appendix 3: notes and guidance for school nurses".)
It is regrettable that a School Health Service is no longer available in some areas. In those where it is, the school nurses (or equivalent) have responsibility for professional advice to staff, parents and children and for carrying out local policies, which should be agreed with the Consultant in Communicable Disease Control. They should provide clear, accurate, up to date information about head lice. This should be done on a regular basis not only when parents’ or teachers’ concern is already raised or there is an "outbreak" in the school. It should generally be integrated with the management of other school health problems rather than as a special separate topic. School nurses should be prepared to teach detection combing to individuals, to families (at their homes if appropriate), and to groups of parents, children and staff as required, and give advice on treatment and prevention. They should not undertake head inspections as a routine screening procedure.
(see "Appendix 4: notes and guidance for head teachers".)
The head teacher should work with the School Nurse and the Consultant in Communicable Disease Control to produce a local protocol and adhere to it. The "alert letters" system should be discontinued.
The Communicable Disease Control Team
(Consultant in Communicable Disease Control and Infection Control Nurse colleagues.)
The Consultant in Communicable Disease Control (CCDC) is responsible for advising other professionals on the control of head lice in the population as a whole. Adequate guidelines and protocols should be produced for all involved professionals including school nurses, school doctors, nursery nurses, general practitioners, health visitors, practice nurses, community paediatricians, infection control teams, pharmacists, and head teachers (see appendices). It is particularly important that school nurses and other community nurses are given adequate support by the CCDC, including regular training sessions and advice about specific problems.
In the absence of suitable nationally produced information leaflets, local leaflets should be produced in consultation with the other professionals. Information should be made available to the public in whatever way possible, including the use of the local news media.
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.
The only reliable method of diagnosing current, active infection with head lice is by detection combing (the technique is described in "Appendix 5: have you got head lice? - notes for families"), though there may be other clues to their presence such as pillows being dirtier than usual in the morning. The technique should be carefully described in protocols for the public and professionals. Misdiagnosis, if detection combing is not used as the criterion, is commonly due to the factors listed below under "Imaginary lice".
Detection combing should be done by parents/family members following advice including leaflets and support. General practitioners, school nurses and other professionals should not necessarily rely on patients’ diagnosis without asking to see the evidence, e.g. a louse stuck on paper with clear adhesive tape.
Many "cases" of head louse infection are not current infections, but are:
- psychogenic itch and revulsion on hearing of other cases in the school, usually by the head teacher’s "alert letter"
- resultant "louse phobia"
- itching scalp due to other causes such as eczema (which in itself may be caused by repeated treatment with insecticides)
- other conditions such as seborrhoea, "dandruff", and hair muffs
- extinct/treated infections but nits still being found
- extinct/treated infection, but itch persisting
- there are also some parents of school children who have a grievance not primarily to do with head lice.
When talks are arranged in schools there is often a low turnout of parents, and typically "the outbreak" is greatly reduced at least for a time thereafter. The "outbreak" that has been reduced is the outbreak of public concern, not of head lice, usually because there was in fact no true outbreak of infection.
A clear distinction should be made between treating head louse infections and "treating" the public reaction, which can be excessive, to perceived infections and "outbreaks". Actions sometimes seem effective in reducing the prevalence of head lice when in fact there has been a reduction in public agitation and concern simply because "something has been seen to be done".
It is bad clinical practice and ethically dubious to recommend as effective those courses of action which are not known to be so on good scientific grounds, or at least on widespread professional experience. Professionals may want "to be seen to be doing something," but may in fact make the problem worse by diverting efforts in the wrong direction.
There are no nationally available leaflets which adequately reflect the opinions given in this Statement., including the Department of Health’s leaflet "The prevention and treatment of head lice" (June 1996). Locally produced leaflets based on this Interim Statement may be the best option for the time being.
Good hair care would seem to be sensible in terms of personal and social education and hygiene, and grooming should be encouraged. Thorough, regular grooming using a fine toothed pocket comb or bristle brush has often been recommended as a means of prevention, of reducing prevalence, and even of treatment of head lice,. There is little evidence supporting the efficacy of this practice, although there has in fact been little reliable scientific assessment made. Caution must therefore be exercised if there are to be claims that it is an effective method of prevention or treatment of head louse infection.
In recent years, mechanical removal of lice by wet combing with the use of conditioner has been put forward as a way of treatment and control. Its effectiveness has to date not been substantiated by any authoritative scientific work. There are anecdotal reports of both its success and failure. If it were demonstrated to work for individuals or individual families, it is unlikely that it would be practicable as a method of community control. When a health adviser is quite sure that appropriate and thorough conventional treatment of a definitely diagnosed case of active current infection has failed, mechanical removal might be tried for individual cases and their families. It may also be considered when patients refuse to accept conventional treatment with insecticides because of concern about their safety.
Wet combing is, of course, an important way of diagnosing current infection (see "Appendix 5: have you got head lice? - notes for families"). Its effectiveness in diagnosis should be clearly distinguished from claims that it also works as a treatment.
Proprietary products which are claimed to repel lice are not recommended. Even if they were effective in protecting the individual from infection, they do not deal with the control of lice in the population, and do not treat existing infections.
(See also Appendix 6: how to treat head lice - notes for families.)
Chemical treatment should be used when current infection is definite, since this is the only method which has been demonstrated scientifically to be effective:
- the three main groups of chemicals (pyrethroids, malathion, and carbaryl) are still effective, even though there is some degree of resistance to each group reported around the country which may require a change in therapy after an initial confirmed failure. The effectiveness probably compares favourably with that of e.g. most commonly used broad-spectrum antibiotics used for other infections.
- unless demonstrated scientifically, "resistance" is more likely to be due to ovicidal failure, misdiagnosis, faulty treatment technique, and (perhaps most common) the failure to eradicate imaginary lice. See the comments under "Diagnosis - Imaginary lice". 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.
Insecticidal preparations against head louse infection should never be recommended or used unless a living, moving louse has been found on the head of at least one family member. Ideally, if one member of the family has current infection, detection combing of all members should be undertaken, and only those found to be infected should be treated.
Many cases of "reinfection" are due to one of the following:
- "imaginary lice"; see under "Diagnosis"
- inadequate or inappropriate treatment
- misdiagnosis, e.g. itch or nits still present after successful eradication of living lice
- the finding of young lice which have not been killed whilst in the egg after the first and before the second application of lotion
True reinfection is usually from close contact in the community rather than specifically from school contact. Carriers of lice are likely not to be aware that they are infected.
Insecticide preparations should not be used for more than one complete treatment of two applications, seven days apart unless a careful assessment has been made, including:
- was there in fact a true infection before application?
- is there in fact a current active infection now?
- are the detected lice simply those which have hatched after a first application
- did the first treatment (two applications) fail?
- if it did, why? (enough lotion, properly applied, all infected contacts treated, etc.)
- is it more probable that the first infection was cleared, but reinfection has occurred?
(see "Appendix 3: notes and guidance for school nurses".)
If it is certain that chemical treatment has failed for an individual or a particular family, then the following actions should be considered:
- retreatment with the same preparation, but ensuring that it is undertaken adequately and for all contacts simultaneously
- retreatment using a different chemical preparation
- supervision and assistance may be appropriate, such as a domiciliary visit to the family by the school nurse or practice nurse
- further thorough attempts to define if there may be a source of recurring infection e.g. a "best friend" and attempts to reduce the likelihood of reinfection of the case/family
- if the problem remains, consider teaching the process of continued physical removal of lice
The three groups of chemicals currently used have a good track record for safety over many years. The number of reported side effects recorded by the Adverse Drugs Reactions section of the Committee on Safety of Medicines is small. For example, there have been only 26 reported side effects to malathion (in 18 individuals) during more than 25 years of use.
Preparations with an alcohol base are contraindicated for people with scalp dermatitis or asthma, although there has only been one reported asthma attack triggered by malathion preparations. Care must, however, be taken that they are used in well ventilated spaces, preferably in the open air, well away from sources of flame and heat such as fires, stoves, cigarettes and hair driers. Care should also be taken to prevent lotion from running over the face and into the eyes.
Many and varied nostrums have over the ages been claimed to be effective in preventing or treating head lice, such as tea tree oil. Some of these are usually harmless e.g. dilute vinegar, some may be dangerous. Essential oils such as tea tree and lavender oil can be quite toxic especially as concentrates.
Other more eccentric "remedies" and "preventives" such as children wearing baseball caps over their heads throughout the day in school are not supported.
Head lice are not primarily a problem of schools, but of the community. Stigma and tradition, however, combine with inadequate public and professional knowledge to continue to hold schools responsible.
Routine head inspections, usually by the school nurse, as a screening measure are without value and should not be done, though examination of an individual (not necessarily in the school) may be indicated to establish the presence of infection in a specific population group (see also Appendix 3; "Notes and guidance for School Nurses"). Before the effective control of head lice became possible with insecticidal lotions, severe cases of infection occurred and head inspections served to detect the very worst and therefore most obvious of them. Nowadays, such gross infections rarely occur. Most active infections are of only a few lice, and routine head inspections are ineffectual at identifying these.
One of the principal causes of unnecessary public alarm is the "alert letter" sent out by head teachers, typically warning parents that "we have head lice in the school". This is an illogical and unnecessary reaction:-
- it is illogical in that it is done in response to reported cases of head lice, which are not easily transmitted widely in the school, but not done for other diseases which are highly transmissible in schools, such as impetigo or chickenpox.
- it is illogical in that most schools will have a few pupils with head lice at any one time. An "alert letter" could be sent out every day of the school year.
- it often converts the usual background level of infection in the school into a pseudo-outbreak in which the parents’ perception is that the school is riddled with lice.
- many parents become convinced they and their children have head lice when they in fact do not (psychogenic itch), or decide to use insecticidal lotions as inappropriate prophylaxis "just in case".
There is provision in the Education Act 1996 (Sections 521-525) for the examination and exclusion of school children by a medical officer duly appointed by the Local Education Authority (the 1944 Act was replaced by the 1996 Act). In many authorities it is not clear if there is such an officer. The process is in any case fraught with complications and doubts.
Exclusion should not be used:
- it cannot ensure the elimination of infection from the family of a child.
- it is unproductive and undesirable overreaction to a problem which is not a public health threat.
- it is inappropriate, being in fact simply an admission of the failure to deal with infection by the community and its professional advisers, but not contributing to a solution.
- it is not used for other conditions with low transmissibility such as verrucae and herpes simplex
Families with continuing or recurring infection with head lice should be assisted and supported as they would be with any other infection; by the concerted support and help of the community (including the school) and of the health professionals (including, for example, visits by the school nurse to the family home).
The word "campaign" suggests intense activity to combat a major problem of the moment. Since, for head lice, there is more likely to be the situation of a fairly steady background prevalence, "campaigns" might in fact fuel the fires of public concern and misapprehension. It might be more sensible to concentrate efforts on providing a regular supply of reliable information about the control of head lice, integrated with other health information. If a specific educational programme, however, is felt to be necessary, it should:
- be regular, not driven by public alarm
- provide accurate information, advice and support
- strongly discourage multiple applications of chemical treatment; an individual assessment of "problem cases" and "repeated reinfections" should be made
- avoid "being seen to do something".
Regional rotation of insecticides in some areas has been standard practice for many years. There are, however, several objections to it, including:
- it was a reasonable hope in the former days of distribution of lotions from health authority clinics that limitation to one preparation could be achieved. This is no longer the case, and, under present health service arrangements a mosaic of treatments is inevitable
- there are doubts about the scientific grounds underlying the concept of attempting to limit treatment to one chemical agent for a period of three years. If it be granted that the chemicals are inappropriately and grossly overused, with inadequate application, then it could be argued (from parallels with antibiotic therapy e.g. against tuberculosis in the third world) that the limitation of therapy to one agent is more likely to encourage the proliferation of resistant lice than would a mosaic system.
- since two of the three chemical groups are available over the counter (only carbaryl being a prescription-only medicine) it is impossible effectively to limit their distribution. There is unnecessary and excessive use, such as by those parents who apply insecticides regularly to their children’s heads "just in case".
- in the light of this, at least so long as two agents remain available off prescription, the rotation of insecticides has no value and should be discontinued.
All chemical insecticidal preparations against head lice should ideally be available only on prescription. This can only be realised if the vital responsibility of primary health care is recognised. The advent of nurse prescribing, and trials of pharmacist prescribing has perhaps made this more achievable. This paper recommends that chemical treatment should only be given to confirmed, active, current cases of head louse infection; this can in fact only be controlled properly if the agents are all made POMs. A further advantage would be the elimination of profit motive in the dispensing of the chemical agents.
Insecticidal shampoos are not effective and should be discontinued. The effectiveness of other chemical preparations should be reviewed.
There has been insufficient support for population research, possibly because head louse infection has not been perceived by health professionals as a serious problem. There is an urgent need for proper peer reviewed studies using standardised techniques to be undertaken. Areas for research include:
- a validated detection method
- the size of the problem; prevalence of infection
- general epidemiology
- intervention studies of treatments
- modelling of transmission dynamics
National leaflets and information should be produced, based on the recommendations contained in this paper. They should be produced by the Working Group in consultation with other involved professionals, and printed by the Department of Health or the Health Education Authority. They should be revised regularly. (Appendix 7 "Head lice; the Truth and the Myths - Notes for Families" may be useful in providing these.)
This document was prepared by:
The "Stafford Group"
Robert Aston, CCDC, Bolton
Harsh Duggal, CCDC, South Staffordshire
John Simpson, CCDC, West Surrey
advised by:
Ian Burgess, Deputy Director, Medical Entomology Centre
for:
The Public Health Medicine Environmental Group Executive Committee
8 May 1998
Adapted for the World Wide Web by:
Dr Peter English, CCDC, East Surrey
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