Head lice resistance: Itching that just won't stop

OBJECTIVE: To evaluate the reports of resistance and cross-resistance to pe diculicides in the head louse (Pediculus capitis), as well as the mechanism s involved. DATA SOURCES: Literature identified through a MEDLINE search (1996-April 20 00) and through other secondary literature databases and/or bibliographies of pertinent articles. DATA SYNTHESIS: Head lice infestation is a common, worldwide problem. The w idespread use of insecticide treatments together with inadequate treatment methods has led to a concern regarding the potential development of resista nt head lice. This literature review examines the reports of resistance of the head louse as well as the purported mechanisms involved. CONCLUSIONS: Current research suggests that head lice resistance exists, bu t little is known regarding the actual incidence of this resistance or whet her this incidence is increasing. More research is needed to assess the sta tus of this problem. Proposed mechanisms for head lice resistance include k nock-down resistance, glutathione S-transferase-based resistance, and mono- oxygenase-based resistance.