The once-common practice of using kerosene to get rid of head lice not only is outdated but it can be extremely dangerous, health-care experts warn.

Donald Damschen and Dr. John Carlile of the University of Nevada School of Medicine in Reno cited the case of a 5-year-old girl who was badly burned when fumes from the kerosene her family used to treat her head lice ignited, creating a fire.In a letter to The New England Journal of Medicine, Damschen and Carlile said the family resorted to kerosene as a "delousing agent" after several shampoos apparently failed to get rid of lice the child acquired at school.

Undiluted lantern fuel was applied to the child's head and she was then taken to the kitchen sink to rinse it off, they said. At that point, a "pilot light in the kitchen stove ignited the fumes, causing flash burns to the child and two other family members," they reported.

The child was the most seriously injured, with burns over 40 percent of her body. She is now undergoing skin grafting procedures.

Although in current medical practice the chemicals lindane and malathion are used to treat head lice, the use of kerosene "has been advocated in the lay medical literature for several decades," Damschen and Carlile said.

Consequently, the "outdated kerosene treatment continues to come to the attention of modern physicians, with tragic consequences in our patient," they said.