The efficacy of Australian essential oils for the treatment of head lice infestation in children: A randomised controlled trial

Background: The increase in resistance of head lice to neurotoxic pediculicides and public concern over their safety has led to an increase in alternative treatments, many of which are poorly researched or even untested.

Methods: A multicentre, randomised, assessor- blind, parallel-group trial (Trial 1) was conducted to compare the safety and efficacy of a head lice treat- ment containing Australian eucalyptus oil and Lep- tospermum petersonii (EO/LP solution; applied thrice with 7-day intervals between applications) with a neurotoxic treatment containing pyrethrins and piperonyl butoxide (P/PB mousse; applied twice with a 7-day interval) in children. A single-blind, open trial (Trial 2) was conducted to assess the efficacy of EO/ LP solution following a single application. In addition, skin irritancy and sensitisation tests using EO/LP solution were performed in adults and children. In vitro tests were performed to further assess the ovici- dal and pediculicidal efficacy of EO/LP solution. 

Results: EO/LP solution was found to be more than twice as effective in curing head lice infestation as P/PB mousse in per-protocol participants (Trial 1; 83% vs 36%, P < 0.0001), and was also found to be 100% pediculicidal following a single application (Trial 2). Adverse events were limited to transient itching, burning or stinging. Further skin testing with the EO/LP solution reported no irritation or sensitisation in adults, or irritation in children. In vitro exposure of lice and eggs to the EO/LP solution resulted in 100% mortality.

Conclusion: The efficacy, safety and relative ease of use of the EO/LP solution make it a viable alter- native in treating head lice.