Head lice infestations (pediculosis capitis) are associated with little morbidity but cause strain and distress to parents, caregivers, and teachers.
Effective pediculicides exist, but head lice in some areas have developed resistance to products with a neurotoxic mode of action.
Products with a physical mode of action are an alternative to neurotoxic treatments; they are nontoxic, and lice are less likely to develop resistance.
Physicians should take an active role in the treatment of head lice infestations by being available to confirm active cases and being knowledgeable about first- and second-line treatment options in their communities.
Knowledge of the life cycle of lice and the mode of transmission emphasize that "no nit" policies in schools are not effective and should be abandoned.
The head louse (Pediculus humanus capitis) is an obligate ectoparasite that lives on human beings and feeds on human blood. Head lice infestation (pediculosis capitis) mainly affects those who are socially active, particularly young children.
History and exam
Key diagnostic factors
- scalp pruritus
- live nymphal or adult louse
- eggs visible on hair shaft within 1 cm of scalp
Other diagnostic factors
- small red papules under hairline at nape of neck
- erythema with honey-colored crust on scalp
- 3 to 12 years of age
- female sex
- close contact with an infested individual
- overcrowding or close living conditions
- low socioeconomic status
- poor hygiene
- contact with contaminated clothes, hair care items, bedding
1st investigations to order
- no tests required
children <2 months of age
children ≥2 months and <2 years of age
children ≥2 years of age and adults
Aicha Salhi, MD
Professor of Dermatology
Faculty of Medicine
University of Algiers
AS declares that she has no competing interests.
Professor Aicha Salhi would like to gratefully acknowledge Professor Hermann Feldmeier and Professor Barbara L. Frankowski, previous contributors to this topic.
HF has received consultant and lecture fees from Pohl-Boskamp GmbH, and Co KG, Hohenlockstedt, Germany, and Almirall Hermal GmbH, Reinbek, Germany; both companies produce various anti-head louse compounds. He is also an author of several references cited in this topic. BLF is an author of a reference cited in this topic.
Richard J. Pollack, PhD
Laboratory of Public Health Entomology
Department of Immunology and Infectious Diseases
Harvard School of Public Health
RJP has received a research donation by Taro Pharmaceuticals (manufacturer of Ovide) and has been compensated as an independent consultant for scientific review services by Topaz Pharmaceuticals, Hatchtech, and ParaPro, each developing products for the US market. RJP holds no financial interest in any of these companies or their products. RJP is an author of several references cited in this topic.
Ian F. Burgess, MSc, MPhil
Medical Entomology Centre
University of Cambridge
IFB has been a consultant to various manufacturers of pharmaceutical products, alternative therapies, and combs for treating louse infections. IFB is an author of a number of references cited in this topic.
Kosta Y. Mumcuoglu, PhD
Department of Parasitology
Hebrew University-Hadassah Medical School
KYM is an author of several references cited in this topic.
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