(Beyond Pesticides, September 25, 2008) Pesticides used as lice treatments can not only have extremely harmful effects on children, they are also not as effective as non- chemical treatments such as utilizing directed hot air, according to researchers. Back-to-school season often coincides with lice outbreaks, and parents should be aware of the risks involved in using lice “shampoos” that contain pesticides and informed of the viability of non-toxic alternatives.
Many of the recent headlines regarding lice in schools include reference to “super lice,” which are difficult to eliminate. These lice have developed resistance to the chemicals commonly used to treat them, such as lindane, malathion and permethrin, and therefore these treatments are increasingly ineffective. Insects frequently develop resistance to pesticides, a fact that emphasizes the importance of strategies both in agriculture and public health that focus on preventing pest outbreaks and dealing with outbreaks in ways that will not lead to resistance.
One such method for eliminating head lice that will not lead to resistant strains of lice is the use of hot air, which desiccates the insects and eggs, thus killing them. Researchers testing six methods of hot air application found that hot air outperforms insecticidal shampoos in killing adult lice and nits (eggs). The study shows that a hand held blow dryer used to apply directed heat on sections of the head for a total of 30 minutes results in 98% mortality of eggs and 55% mortality of adult lice. A specially developed hot air applicator named the “lousebuster” results in equal egg mortality and higher (80%) adult lice mortality. Both of these treatments are more effective than chemical shampoos. The authors advocate for the institutional adoption of devices such as the lousebuster.
Chemical methods for dealing with lice are highly toxic for humans and the environment. Lindane is particularly toxic and is also bioaccumulative. The last remaining agricultural uses of lindane were cancelled in 2006, and the only remaining use, as a treatment for head lice, is regulated by the Food and Drug Administration (FDA). It was banned in California in 2000 because of high levels of water contamination. Following the ban, water contamination drastically declined, and an increase in head lice cases was not reported.
For more on how to deal with lice without chemicals, visit our factsheet (note that this was published prior to this study, and does not include much information on hot air treatment).
TAKE ACTION: Inform your school administrators about the alternatives to chemical shampoos for lice treatment, as well as the dangers chemical treatments pose to children. Pressure them to inform parents of non-toxic lice treatments when they disseminate information on lice. Encourage them to obtain devices such as the lousebuster to enable the most effective treatment of students with lice.