BACKGROUND: Over-the-counter insecticidal solutions continue to be the mainstream treatment for most cases of head lice. Recorded insecticidal activity 15 years ago was at 100%, with ovicidal kill at 80%. Recently scattered accounts of possible resistance have surfaced. OBJECTIVE: This article is to document the general consensus that head lice are becoming resistant to standard over-the-counter therapies. METHODS: Direct testing of lethality of adult lice with permethrin and pyrethroid was assessed. RESULTS: Present over-the-counter products proved to be successful in only 9 of 32 head lice tested (28% insecticidal activity). CONCLUSIONS: Our series of cases further documents that over-the-counter head lice preparations no longer achieve high levels of insecticidal activity, suggesting increased resistance to these insecticides.
BACKGROUND: Over-the-counter insecticidal solutions continue to be the mainstream treatment for most cases of head lice. Recorded insecticidal activity 15 years ago was at 100%, with ovicidal kill at 80%. Recently scattered accounts of possible resistance have surfaced. OBJECTIVE: This article is to document the general consensus that head lice are becoming resistant to standard over-the-counter therapies. METHODS: Direct testing of lethality of adult lice with permethrin and pyrethroid was assessed. RESULTS: Present over-the-counter products proved to be successful in only 9 of 32 head lice tested (28% insecticidal activity). CONCLUSIONS: Our series of cases further documents that over-the-counter head lice preparations no longer achieve high levels of insecticidal activity, suggesting increased resistance to these insecticides.
Authors: Kyong Sup Yoon; Domenic J Previte; Hilliary E Hodgdon; Bryan C Poole; Deok Ho Kwon; Gamal E Abo El-Ghar; Si Hyeock Lee; J Marshall Clark Journal: J Med Entomol Date: 2014-03 Impact factor: 2.278
Authors: Kosta Y Mumcuoglu; Richard J Pollack; David L Reed; Stephen C Barker; Shirley Gordon; Ariel C Toloza; Maria I Picollo; Aysegul Taylan-Ozkan; Olivier Chosidow; Birgit Habedank; Joanna Ibarra; Terri L Meinking; Robert H Vander Stichele Journal: Int J Dermatol Date: 2020-08-07 Impact factor: 2.736