Once again it's back to school for millions of children nationwide. With this yearly event comes the inevitable arrival of pediculosis capitis—head lice—the bane of children who congregate in close quarters. Three million new cases are reported annually in the United States. Resistance is a growing concern as lice simply ignore conventional pediculicides. As experts note that resistance is much less likely to develop to therapies that do not work on a chemical level, a new wave of therapies use natural and non-neurotoxic treatments.

As a non-neurotoxic treatment, Fairy Tales Hair Care for Children—makers of the natural head lice prevention hair care line, Rosemary Repel—has introduced Lice Good-Bye, available at www.fairytaleshaircare.com and retailing at $15.95. Then there is Lice Good-Bye Mousse, an enzyme-based shampoo in a pump bottle, which dissolves the glue that nits produce to attach themselves to their host's hair. This enables parents to remove lice and nits from the hair more efficiently. The entire wet hair is covered with "puffs" of mousse. Mild pressure is used to work the mousse through wet hair. This is repeated at least three times or until the entire bottle is used for one person. The mousse is left on for 30 minutes, then the hair is combed and rinsed.

There are also lice treatments in development. Resultz (Piedmont Pharmaceuticals), an experimental rinse, purportedly kills head lice in 10 minutes without causing intolerable adverse effects in children as young as two years and adults up to 59 years. "The product really works well to get rid of head lice, which are becoming more and more resistant to standard treatments," said Nalini Kaul, Ph.D., a scientist at Hill Top Research, Winnipeg, Manitoba, Canada. "The results of our study with the experimental pediculicide demonstrate that it is a safe alternative therapy for the control of head lice," Kaul said. The rinse contains 50% isopropyl myristate and 50% ST-cyclomethicone. The product has been submitted to Health Canada, where it is under regulatory review. U.S. phase III trials are expected to commence sometime this year.

Nuvo lotion (Family Dermatology Medical Office) is the first of a new investigational class of nontoxic lotions to treat head lice. Called a DSP (dry-on, suffocation-based pediculicide), the lotion is applied to wet hair and then blown dry with a hair drier, to form an adherent film. This "shrink-wrapped" film layer completely covers the louse, plugging its breathing holes (spiracles) and causing death by suffocation. The dried lotion is left on the hair for at least eight hours. It can then be washed out with a regular shampoo. Development of resistance would require complex changes in the breathing mechanism and would be unlikely to occur. Nuvo lotion has completed a proof-of-concept study, which was published as the lead article in the September 2004 issue of Pediatrics and was also featured at the Annual Pediatric Infectious Disease Conference held this past July in Aspen.

Also awaiting approval for the treatment of lice is Foamix's PerFoam, made with 1% permethrin and two proprietary enhancers. PerFoam is an alcohol-free, drip-free foam that was demonstrated to be safe and to have a 96% efficacy rate in a phase II/III study. In the study, PerFoam was applied to the hair for 10 minutes and then washed. Treatment was repeated 10 days later. The company expects that the new foam formulation will offset the resistance to permethrin seen with shampoo, lotion, and cream rinse formulations. A 2006/07 launch is anticipated for PerFoam.

In other news, the Centers for Disease Control & Prevention warned that topical lindane, once the drug of choice for treating head lice, can cause vomiting and seizures if accidentally swallowed. Morbidity and Mortality Weekly Report featured cases of poisoning that seem to be caused by patients mistaking lindane for an oral medicine. This happens because some pharmacies repackage bottles of bulk lindane into smaller bottles resembling those used for liquid oral medications. Therefore, pharmacists "should not transfer lindane to other containers and should only dispense lindane in manufacturer-provided 1- or 2-ounce containers," the report advises. The use of lindane for treating lice should be reserved for when first-line therapies have failed or are poorly tolerated.