Elsevier

The Lancet

Volume 355, Issue 9206, 4 March 2000, Pages 819-826
The Lancet

Seminar
Scabies and pediculosis

https://doi.org/10.1016/S0140-6736(99)09458-1Get rights and content

Summary

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. They have been known since antiquity and are distributed worldwide. Clusters of infestation occur—for example, scabies affecting immunocompromised individuals or patients and staff in hospitals and nursing homes for the elderly, and pediculosis affecting schoolchildren or homeless people. Associations with other disorders are common: infections with human T-cell leukaemia/lymphoma virus I (HTLV-I) and HIV are associated with scabies, and trench fever and exanthematous typhus with pediculosis. Specific forms of scabies, including bullous scabies or localised crusted scabies, may be misdiagnosed. Moreover, definitive parasitic diagnosis can be difficult to obtain, and the value of new techniques remains to be confirmed. Difficulties in management have returned scabies and pediculosis to the limelight.

Section snippets

Aetiology and epidemiolog

Scabies has been known for over 2500 years. It is caused by a mite, Sarcoptes scabiei var hominis, an obligate human parasite that burrows tunnels downwards into the epidermis (not deeper than the stratum granulosum). Mites of all developmental stages tunnel into the stratum corneum and deposit faeces behind them; the female also lays eggs in the tunnels. Scabies occurs in both sexes and all age-groups. Since it is transmitted by skin-to-skin contact, sexual transmission is common, as is

Topical scabicides

The choice of scabicide must be based on effectiveness and potential toxicity, extent of secondary eczematisation, and the patient's age. Panel 1 lists agents used as scabicides worldwide; the recommended drugs vary from one country to another. For most, there have been no controlled studies documenting that two applications are better than one.

Benzyl benzoate is used alone or in combination with sulfiram. Different treatment regimens have been proposed (swabbing only once, two applications

Aetiology and epidemiology

Pediculosis has been known for over 10 000 years. The oldest eggs (6900–6300 BC) were found in the Nahal Herman Cave in the Judean Desert.32 A louse egg was discovered attached to a hair of a pregnant woman buried under the ashes of Herculaneum (Aug 24, 79 AD).33

Lice are blood-sucking insects and specific parasites of human beings. Pediculus humanus var capitis lives on the head (head lice); P humanus var corporis lives in the person's clothes, benefiting from the warmth and feeding on the body

Head lice

Many agents are available. The effectiveness of combs (plastic, aluminium, thermal, and electronic) remains to be established by rigorous randomised clinical trials. Head shaving should be avoided whenever possible because it is humiliating, especially in girls.

Most treatments are sold over the counter by pharmacists. In Glasgow, Scotland, 19 000–36 000 bottles of insecticide were bought by the public in 1991. Sales of all licensed products rose 3·7-fold between 1990 and 1995 in England and

References (64)

  • O Chosidow et al.

    Controlled study of malathion and d -phenothrin lotions for Pediculus humanus var capitis -infested schoolchildren

    Lancet

    (1994)
  • ER Clore et al.

    A comparative study of seven pediculicides and their packaged nit removal combs

    J Pediatr Health Care

    (1993)
  • SF Walton et al.

    Crusted scabies: a molecular analysis of Sarcoptes scabiei variety hominis populations from patients with repeated infestations

    Clin Infect Dis

    (1999)
  • M Orkin

    Scabies: what's new?

    Curr Probl Dermatol

    (1995)
  • DL Holness et al.

    Scabies in chronic health care institutions

    Arch Dermatol

    (1992)
  • D Taplin et al.

    Comparison of crotamiton 10% cream (Eurax) and permethrin 5% cream (Elimite) for the treatment of scabies in children

    Pediatr Dermatol

    (1990)
  • AA Hegazy et al.

    Epidemiology and control of scabies in an Egyptian village

    Int J Dermatol

    (1999)
  • P Del Giudice et al.

    Is crusted (Norwegian) scabies a marker of adult T cell leukemia/lymphoma in human T lymphotropic virus type I-seropositive patients?

    J Infect Dis

    (1997)
  • AJ Mancini et al.

    Scabies and infantile acropustulosis are difficult to differentiate from one another

    Pediatr Dermatol

    (1998)
  • AM Farrell et al.

    Crusted scabies with scalp involvement in HIV-1 infection

    Br J Dermatol

    (1998)
  • A Alinovi et al.

    Scabietic infestation of the scalp: a clue for puzzling relapses

    J Am Acad Dermatol

    (1994)
  • G Argenziano et al.

    Epiluminescence microscopy: a new approach to in vivo detection of

    Sarcoptes scabiei. Arch Dermatol

    (1997)
  • MW Schultz et al.

    Comparative study of 5% permethrin cream and 1% lindane lotion for the treatment of scabies

    Arch Dermatol

    (1990)
  • TJ Franz et al.

    Comparative percutaneous absorption of lindane and permethrin

    Arch Dermatol

    (1996)
  • TL Meinking et al.

    Safety of permethrin vs lindane for the treatment of scabies

    Arch Dermatol

    (1996)
  • DA Burns

    Scabies

  • MYM Youssef et al.

    Topical application of ivermectin for human ectoparasites

    Am J Trop Med Hyg

    (1995)
  • P Del Guidice et al.

    Ivermectin: a new therapeutic weapon in dermatology?

    Arch Dermatol

    (1999)
  • E Macotela-Ruiz et al.

    Tratamiento de la escabiasis con ivermectina por via oral

    Gac Med Mex

    (1993)
  • P Glaziou et al.

    Comparison of ivermectin and benzyl benzoate for treatment of scabies

    Trop Med Parasitol

    (1993)
  • EN Chouela et al.

    Equivalent therapeutic efficacy and safety of ivermectin and lindane in the treatment of human scabies

    Arch Dermatol

    (1999)
  • TL Meinking et al.

    The treatment of scabies with ivermectin

    N Engl J Med

    (1995)
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