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Pediculosis capitis

  • Overview
  • Theory
  • Diagnosis
  • Management
  • Follow up
  • Resources
Last reviewed: 10 Sep 2025
Last updated: 23 Apr 2025

Summary

Definition

History and exam

Key diagnostic factors

  • scalp pruritus
  • live nymphal or adult louse
  • eggs visible on hair shaft within 1 cm of scalp
Full details

Other diagnostic factors

  • small red papules under hairline at nape of neck
  • lymphadenopathy
  • erythema with honey-colored crust on scalp
Full details

Risk factors

  • 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
Full details

Diagnostic tests

1st tests to order

  • no tests required
Full details

Treatment algorithm

ACUTE

children <2 months of age

children ≥2 months and <2 years of age

children ≥2 years of age and adults

Contributors

Authors

Aicha Salhi, MD

Professor of Dermatology

Faculty of Medicine

University of Algiers

Algeria

Disclosures

AS declares that she has no competing interests.

Acknowledgements

Professor Aicha Salhi would like to gratefully acknowledge Professor Hermann Feldmeier and Professor Barbara L. Frankowski, previous contributors to this topic.

Disclosures

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.

Peer reviewers

Richard J. Pollack, PhD

Research Associate

Laboratory of Public Health Entomology

Department of Immunology and Infectious Diseases

Harvard School of Public Health

Boston

MA

Disclosures

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

Professor

Director

Medical Entomology Centre

University of Cambridge

Cambridge

UK

Disclosures

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

Professor

Department of Parasitology

Hebrew University-Hadassah Medical School

Jerusalem

Israel

Disclosures

KYM is an author of several references cited in this topic.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

American Academy of Pediatrics, Nolt D, Moore S, et al. Head Lice. Pediatrics. 2022 Oct 1;150(4):e2022059282.Full text  Abstract

Cummings C, Finlay JC, MacDonald NE et al. Head lice infestations: a clinical update. Paediatr Child Health. 2024 Jan 11;23(1):e18-24.Full text

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

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