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Primary Care

Treatment of head louse infestation with 4% dimeticone lotion: randomised controlled equivalence trial

BMJ 2005; 330 doi: (Published 16 June 2005) Cite this as: BMJ 2005;330:1423
  1. Ian F Burgess, director (ian{at},
  2. Christine M Brown, study coordinator1,
  3. Peter N Lee, statistician2
  1. 1 Insect Research and Development, Shepreth, Royston SG8 6QZ
  2. 2 P N Lee Statistics and Computing, Sutton, Surrey SM2 5DA
  1. Correspondence to: I F Burgess
  • Accepted 15 May 2005


Objective To evaluate the efficacy and safety of 4% dimeticone lotion for treatment of head louse infestation.

Design Randomised controlled equivalence trial.

Setting Community, with home visits.

Participants 214 young people aged 4 to 18 years and 39 adults with active head louse infestation.

Interventions Two applications seven days apart of either 4.0% dimeticone lotion, applied for eight hours or overnight, or 0.5% phenothrin liquid, applied for 12 hours or overnight.

Outcome measures Cure of infestation (no evidence of head lice after second treatment) or reinfestation after cure.

Results Cure or reinfestation after cure occurred in 89 of 127 (70%) participants treated with dimeticone and 94 of 125 (75%) treated with phenothrin (difference -5%, 95% confidence interval -16% to 6%). Per protocol analysis showed that 84 of 121 (69%) participants were cured with dimeticone and 90 of 116 (78%) were cured with phenothrin. Irritant reactions occurred significantly less with dimeticone (3/127, 2%) than with phenothrin (11/125, 9%; difference -6%, -12% to -1%). Per protocol this was 3 of 121 (3%) participants treated with dimeticone and 10 of 116 (9%) treated with phenothrin (difference -6%, -12% to -0.3%).

Conclusion Dimeticone lotion cures head louse infestation. Dimeticone seems less irritant than existing treatments and has a physical action on lice that should not be affected by resistance to neurotoxic insecticides.


  • Contributors IFB conceived and designed the study, interpreted the data, wrote the paper, and contributed to the execution of the study. He will act as guarantor for the paper. CMB conceived, designed, and coordinated the study, was responsible for screening, treatments and assessments, interpreted the data, and helped write the paper. PNL was responsible for the randomisation process and statistical analyses, and helped interpret the findings and write the paper. Treatments and assessments were carried out by Anne Scarlett, Audrey Pepperman, Caroline Priestley, Nazma Burgess, and Matthew Southward. Kate King monitored and evaluated adverse events and acted as the medical contact throughout the study. Sam Shuster was the dermatological medical expert. Katharine Young and Yvonne Cooper entered the data for statistical analysis and John Fry provided statistical assistance.

  • Funding Kerris Pharmaceuticals, Jersey, which had no role in the design, execution, or interpretation of the study.

  • Competing interests IFB has been a consultant to various makers of pharmaceutical products, alternative therapies, and combs for treating louse infestations. PNL has analysed similar studies for other pharmaceutical companies.

  • Ethical approval Ethical approval for this study was granted by Cambridge research ethics committee, and issues related to the locality were approved by Peterborough and Fenland and Huntingdon local research ethics committees. This clinical trial was monitored and audited by Covance.

  • Accepted 15 May 2005
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