Killing lice with hair dryer is more than a lot of hot air

January 1, 2007

Investigators tested six different methods for delivering hot air to the scalps of 169 children infested with lice to determine how well each method kills lice and their eggs. The children, who were at least 6 years of age, were treated at home and each subject served as his or her own control. This is how it worked: Investigators combed one side of the scalp, removing all lice and eggs, and preserved them in a portable incubator. Next, they treated the whole scalp with one of the six methods, then combed the other side of the scalp and again preserved all lice and eggs. In this way, investigators could compare the percentage of viable lice and eggs removed from the pretreatment and posttreatment sides of the scalp.

Investigators tested six different methods for delivering hot air to the scalps of 169 children infested with lice to determine how well each method kills lice and their eggs. The children, who were at least 6 years of age, were treated at home and each subject served as his or her own control. This is how it worked: Investigators combed one side of the scalp, removing all lice and eggs, and preserved them in a portable incubator. Next, they treated the whole scalp with one of the six methods, then combed the other side of the scalp and again preserved all lice and eggs. In this way, investigators could compare the percentage of viable lice and eggs removed from the pretreatment and posttreatment sides of the scalp.

The six methods for heating the scalp of infested children included using a bonnet-style hair dryer, a handheld blow dryer (using two different methods of sectioning the hair), a wall-mounted dryer, and a custom-built, high-volume hot-air blower called the LouseBuster, which was tested in two ways: with hair sectioning and with a custom-designed hand piece with teeth that facilitate exposure of the hair's roots to hot air. Each treatment took about 30 minutes. All six methods successfully killed a high percentage of louse eggs (> 88%) but varied considerably in how well they dispensed with hatched lice.

The LouseBuster with hand piece had the best results, nearly 100% egg mortality and 80% hatched lice mortality. Furthermore, the device was effective when operated at a slightly cooler temperature than a standard blow dryer, and few children found it uncomfortable. Finally, follow-up examinations of the children one week after treatment with this method showed that 10 of the 11 were completely cured of lice-and the 11th had just one live male louse (Goates BM et al: Pediatrics 2006;118:1962).

Imagine what would happen if the LouseBuster was kept in schools for use by school nurses, staff, or trained volunteers. Children with lice could be diagnosed, treated, and returned to class. Hot air: a cool idea that could eliminate the millions of school days lost to head lice.