Paeds · paediatric-dermatology
Scabies, lice and infestations
Also known as scabies · Sarcoptes scabiei · crusted scabies · Norwegian scabies · head lice · pediculosis capitis · pubic lice · phthiriasis · body lice · ectoparasite infestation
Human ectoparasite infestations of childhood — scabies (Sarcoptes scabiei), head lice (Pediculus humanus capitis), pubic lice and body lice — presenting with characteristic itchy burrows or nits, diagnosed clinically using the 2020 IACS criteria, and managed with permethrin or ivermectin while treating all household contacts on the same day.
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Target exams
Red flags
- thick hyperkeratotic crusts with little itch suggesting crusted (Norwegian) scabies that is highly contagious by brief contact
- rapidly spreading weeping lesions with fever indicating secondary bacterial sepsis from impetiginised scabies or lice
- haematuria, oedema or hypertension pointing to acute post-streptococcal glomerulonephritis in an endemic setting
- pubic lice or nits on the eyelashes of a child prompting a measured safeguarding assessment alongside non-sexual transmission
- itch that fails to settle despite correct whole-body permethrin and contact treatment suggesting crusted disease, resistance or re-infestation
- an infant under two months with extensive pustular lesions on the palms and soles requiring review before topical scabicide
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Clinical exam formats
Board mappings
- recognise and manage scabies and pediculosis in children
- explain household treatment and the importance of treating all contacts on the same day
- distinguish classic from crusted scabies and select permethrin versus ivermectin
- manage complications, Indigenous disease and resistance
- high-yield: IACS criteria, permethrin regimen, household treatment, lice management, crusted scabies
- short-case assessment and counselling of a child with scabies or pediculosis
- scabies and lice — recognise, treat the child and contacts, recognise crusted scabies
- scabies mite and burrow distribution, permethrin and ivermectin dosing, head lice treatment and resistance
- assess and counsel the family of a child with scabies or head lice
- scabies and pediculosis — diagnosis and treatment of the child and contacts
- recognise and treat scabies and lice; isolate crusted scabies; manage secondary infection
- scabies and lice — recognise, treat and break household transmission
Overview & Definition
A school-age child who cannot sleep because of an itch that burns worst at night, with burrows in the finger-webs and a sibling scratching just as badly, is the everyday face of scabies. Human ectoparasite infestations are infections of the skin by arthropods that have adapted to live on people: the scabies mite burrows into the stratum corneum, while lice cling to hair or clothing and feed on blood. Scabies alone affects more than 200 million people at any time, and in remote and overcrowded communities it is one of the commonest reasons a child presents to a clinician. [2]
The clinical thread that unites scabies and pediculosis is itch, but the mechanism differs. Scabies itch is a delayed allergy to mite antigens that takes weeks to develop, which is why a first infestation is silent at first and overwhelming by the time it is recognised. Louse itch is an immediate reaction to bites and saliva, together with the local damage caused by scratching. Both are contagious, both invite secondary bacterial infection, and both demand treatment of the child together with every household and close contact on the same day. [3]
References11ShowHide
- [1]Engelman D, Fuller LC, Steer AC The 2020 International Alliance for the Control of Scabies Consensus Criteria for the Diagnosis of Scabies. Br J Dermatol, 2020.PMID 32034956
- [2]Karimkhani C, Colombara DV, Drucker AM The global burden of scabies: a cross-sectional analysis from the Global Burden of Disease Study 2015. Lancet Infect Dis, 2017.PMID 28941561
- [3]Currie BJ, McCarthy JS Permethrin and ivermectin for scabies. N Engl J Med, 2010.PMID 20181973
- [4]Dhana A, Yen H, Okhovat JP, et al. Ivermectin versus permethrin in the treatment of scabies: A systematic review and meta-analysis of randomized controlled trials. J Am Acad Dermatol, 2018.PMID 29241784
- [5]Romani L, Whitfeld MJ, Koroivueta J Mass Drug Administration for Scabies Control in a Population with Endemic Disease. N Engl J Med, 2015.PMID 26650152
- [6]Aung PTZ, Cuningham W, Hwang K Scabies and risk of skin sores in remote Australian Aboriginal communities: A self-controlled case series study. PLoS Negl Trop Dis, 2018.PMID 30044780
- [7]Mounsey KE, Holt DC, McCarthy J Scabies: molecular perspectives and therapeutic implications in the face of emerging drug resistance. Future Microbiol, 2008.PMID 18230034
- [8]Meinking TL, Villar ME, Vicaria M The clinical trials supporting benzyl alcohol lotion 5% (Ulesfia): a safe and effective topical treatment for head lice (pediculosis humanus capitis). Pediatr Dermatol, 2010.PMID 20199404
- [9]Deeks LS, Naunton M, Currie MJ, et al. Topical ivermectin 0.5% lotion for treatment of head lice. Ann Pharmacother, 2013.PMID 24259731
- [10]Heukelbach J, Pilger D, Oliveira FA, et al. A highly efficacious pediculicide based on dimeticone: randomized observer blinded comparative trial. BMC Infect Dis, 2008.PMID 18783606
- [11]Cole SW, Lundquist LM Spinosad for treatment of head lice infestation. Ann Pharmacother, 2011.PMID 21750308