“Prescription” or “over the counter” pesticides and insecticides designed to poison lice can be toxic. These products can be absorbed directly into your child’s system through the scalp.
Examples:
Lindane: Lindane, a neurotoxin that is absorbed through the skin, is used in the prescription-only lice shampoo, Kwell. Ann Heil, a senior engineer with the Sanitation Districts of Los Angeles County, “Lindane belongs to the same family of chemicals as DDT and PCBs, which have been banned in the United States.” This chemical, which is absorbed through the skin, has been in use since the 1950s. It is created by mixing chlorine gas with benzene and filtering out the particulate solids that result. Chlorine gas is a poison and benzene is a well-known carcinogen. Lindane has been consistently listed in the top chemicals of concern by the Agency for Toxic Substances and Disease Registry. According to the Centennial Edition of the Merck Index, poisoning with lindane may occur by ingestion, inhalation, or skin absorption—all of which are possible with treatment with head lice shampoos. Possible symptoms of lindane poisoning include headache, nausea, vomiting, diarrhea, tremors, weakness, convulsions, difficulty breathing, low blood oxygen levels, and circulatory collapse. Case-controlled research shows a significant association between the incidences of brain tumors in children with the use of lindane-containing lice shampoos Lindane, has been banned in more than 50 countries and in California, but is still available in the United States.
Malathion: This toxic pesticide is used in the prescription-only lice remedy “Ovide”. Malathion is a chemical that was developed by the Swiss chemical giant Ciba-Geigy back in the 1950s as an agricultural crop insecticide and for pest control in homes and gardens. Very quickly thereafter, problems began occurring. It turns out that children are especially susceptible to the effects of Malathion. Studies have shown links between regular exposure to Malathion and various human maladies, including non-Hodgkin’s lymphoma, childhood leukemia, anemia, chromosome damage, and weakened immune systems. It has also been known to cause flu like symptoms and allergic reactions in children and adults alike. Malathion exposure can occur through inhalation or absorption through the skin. According to the EPA, this chemical can over stimulate the nervous system and cause nausea, dizziness, confusion, and, at very high exposures (such as those from major spills or accidents), respiratory paralysis and death.
Pyrethrums and Pyrethoids: These two non-prescription, over the counter pesticides, are used in as several lice shampoos. Pyrethrum is derived from the chrysanthemum flower and is considered a pesticide that has been deemed dangerous enough to be banned from agricultural use in food production. It may cause pneumonia, muscle paralysis, vomiting, asthma, and death due to respiratory failure. Pyrethroids, the synthetic chemical counterpart used in some lice treatments, may have similar effects. Severe allergic reaction is another common side effect associated with both pyrethrums and pyrethoids.