This article was first published by our sister publisher, Contemporary Pediatrics®. (https://www.contemporarypediatrics.com/view/the-dx-and-rx-of-head-lice)
Humans have harbored head lice since time immemorial.1 It is a global public health problem that affects millions of people every year, especially in developing countries.2
While common in all age groups, pediculosis (or head lice infestation) is more common in school-age children.3 This is due to close contact in daycare, on play dates, and in the classroom with other people who may have head lice. If not detected early and treated appropriately, this condition can last for weeks, months, or years.4 The CDC estimates that between 6 and 12 million children aged 3 to 11 years are affected each year.5
The COVID-19 lockdown presents an unprecedented example where the number of head lice cases has significantly reduced due to social distancing and children being at home. However, experts quickly realized that it was impossible to eliminate due to the temporary nature of the social distancing period.6 It is important to understand that the psychosocial and social implications of this disease outweigh the medical problems. Children affected by head lice may often complain of itching of the scalp, neck and ears as the main symptom. However, caregivers’ anxiety and fear of being ostracized is a broader concern that doctors must also address.4,7
The head louse (or Pediculus humanus capitis) is an obligate ectoparasite of the human scalp, in which it feeds exclusively on blood. The 6-legged insects are wingless and the adults are about 2 to 4 mm long. Often there are fewer than 10 adult lice on infested children.1,8,9
The female flea lives up to 3 to 4 weeks and, once mature, can lay up to 10 eggs per day. The eggs are then firmly attached to the human hair shaft close to the scalp (approximately 2 mm) with a glue-like substance produced by lice. The human scalp serves as an ideal environment for the eggs to hatch in about 8 to 12 days. The nymph then undergoes a 3-stage molt before becoming an adult in a process that takes approximately 8 to 15 days. If left untreated, the cycle repeats every 3 weeks.9-11
Lice feed on human scalp after secreting saliva which contains anticoagulant properties, which makes the epidermis conducive to sucking human blood. Pruritus occurs within 2 to 4 weeks due to sensitivity to saliva. In some cases, it may take 4 to 6 months for pruritus to appear due to delayed sensitization.1
The most common mode of transmission occurs through direct contact with the hair of an infected person, most commonly through head-to-head contact.9,1 Fleas do not hop or hop; they can only crawl quickly (as fast as 23 cm/min). Head lice in humans are not transmitted by pets.9 The role of fomites in transmission continues to be a controversial mystery.12
Diagnosis of pediculosis requires expertise and experience. Infestation is confirmed by the presence of nits or lice on human hair less than 1 cm from the scalp (Figure 1 and 2). This can be done with a naked eye exam, assisted with a hand-held magnification device by a doctor or caregiver at school. Using a sharp-toothed flea comb to collect active mites has been shown to be 4 times more effective and 2 times faster than direct visualization.1,9 The presence of nits alone will not confirm the diagnosis, as microscopy is required to determine viability (Figure 3).
Adequate care should be taken to ensure that the scalp is not peeled when looking for lice or nits, as sharp-toothed combs can cause injury to the scalp. Experts recommend using regular (olive, sunflower, corn) oils and hair conditioner before combing to slow down the movement of lice. 13 Wet combing may be considered for children younger than 2 years.
Health care professionals are advised to start treatment once the diagnosis is confirmed. Two approved treatment options include topical pediculicides and oral agents.9 Topical agents include 1% permethrin (synthetic pyrethroid) and pyrethrin (natural extract), both of which are neurotoxic to ticks and have shown excellent results. Resistance has been reported to this group due to knockdown resistance gene mutations.1
If the above mentioned agents fail, some other topical medications that are recommended include isopropyl myristate/ST-cyclomethicone solution, dimethicone solution, 0.5% ivermectin lotion, 0.5% malathion lotion, and 0.9% spinosad suspension. 9 Another oral agent that has been shown to be effective is ivermectin tablets, 3 mg. It is important to emphasize the instructions for use and when to give each drug to parents. Lindane is no longer an acceptable therapy because of the potential risk of neurotoxicity.1,9
Topical agents should be rinsed with cool or warm water in a sink rather than bathing to limit skin exposure.10 Do not use hot water, as it can cause vasodilation, increasing the chances of absorption.
Treatment is considered successful if no ticks are detected after re-examination at the end of treatment. If live lice are still present after the recommended period, another agent should be used with a different active ingredient.14
Head lice infestation is a condition that affects a large population of children globally. Regular head checks can help detect this disease early. As a pediatrician, it is important to create awareness about the condition, counsel caregivers and parents about treatment with anti-lice medications, and address the psychosocial stress and stigma associated with the disease. Introducing customized public health measures to control the disease is also very important.7 Furthermore, collaborative initiatives with primary schools that emphasize early detection of diseases in children by school teachers and caregivers can help reduce the burden of these diseases. Eliminating policies without scientific evidence, such as no-nit policies, is key to safeguarding the well-being of children and parents.15
Children are allowed to go to school the next day after application of the topical therapy. The school nurse can check for head lice on the tenth day after treatment.15
Muhammad Aamir Anies is in his final year of medical school at Kanachur Institute of Medical Sciences in Mangalore, India.
1. Nolt D, Moore S, Yan AC, Melnick L; Communicable Disease Committee, Outpatient Practice and Medicine Committee, Dermatology Section. Head lice. Pediatrics. 2022;150(4):e2022059282. doi:10.1542/peds.2022-059282
[ PubMed ][ Referensi Silang ]2. Fu YT, Yao C, Deng YP, et al. Human pediculosis, a global public health problem. Infect Poverty Dis. 2022;11(1):58. doi:10.1186/s40249-022-00986-w
3. Hosseini SH, Rajabzadeh R, Shoraka V, Avaznia A, Shoraka HR. Prevalence of pediculosis and its related factors among primary school students in the Maneh-va Semelghan district. J North Khorasan Univ Med Sci.2014; 6:50
4.Gordon SC. Shared susceptibility: theories of treating children with persistent head lice. J Sch Nurs. 2007;23(5):283-292. doi:10.1177/10598405070230050701
5. Parasites: epidemiology & risk factors. CDC. Reviewed October 15, 2019. Retrieved June 21, 2023. https://www.cdc.gov/parasites/lice/head/epi.html
6. Jeffay N. Scratch that: lockdowns are doom for head lice, experts say. Israelite Age. 22 May 2020. Accessed 21 June 2023. https://www.timesofisrael.com/lockdown-was-calamity-for-head-lice-experts-say/
7. Neuberg M, Banfić I, Cikać T, Ribić R, Zember S, Meštrović T. Knowledge, attitudes, psychosocial perspectives and applied epidemiology in head lice control (head lice) in Croatian preschool children: a qualitative study of child care professionals and health coordinators. Children (Basel). 2022;9(1):66. doi:10.3390/children9010066
8. AlexanderJOD. Arthropods and Human Skin. Springer Verlag; 1984
9. Cummings C, Finlay JC, MacDonald NE. Head lice infestation: a clinical update. Pediatric Children’s Health. 2018;23(1):e18-e24. doi:10.1093/pch/pxx165
[ PubMed ]10. Takano-Lee M, Yoon KS, Edman JD, Mullens BA, Clark JM. Maintenance of in vivo and in vitro pediculus humanus capitis (Anoplura: Pediculidae). J Med Entomol. 2003;40(5):628-635. doi:10.1603/0022-2585-40.5.628
11. Burkhart CN. Fomite transmission by head lice: ongoing controversy. Lancet. 2003;361(9352):99-100. doi:10.1016/S0140-6736(03)12243-X
12. Burgess I. Comb detection. Nur Times. 2002;98(46):57.
13. Leung AKC, Lam JM, Leong KF, Barankin B, Hon KL. Pediatrics: how to manage pediculosis capitis. Drug Context. 2022;11:2021-11-3. doi:10.7573/dec.2021-11-3
14. Mumcuoglu KY, Pollack RJ, Reed DL, et al. International recommendations for effective head lice infestation control. Dermatol Int J. 2021;60(3):272-280