Mayonnaise, olive oil and petroleum jelly are popular home remedies for suffocating head lice and, at first blush, they appear to work. Unfortunately, lice have external structures called spiracles that protect the entry points to their breathing apparatus. Closing the spiracles protects the lice from the suffocating effects of the home remedies and, when the agent is removed, the lice often appear to have a miraculous resurrection. A newly approved over-the-counter drug called Ulesfia seems to get around this problem by shocking the spiracles open, according to a report in the journal Pediatric Dermatology.
Of course, over-the-counter products containing the neurotoxin permethrin and prescription drugs containing malathion and lindane are also available. Because these contain neurotoxins, however, they can be used only every 10 days or so and are not appropriate for very young children. Reinfestation often occurs much quicker and the lice, furthermore, appear to be developing resistance to the pesticides.
Ulesfia, manufactured by Shionogi Pharma Inc. of Atlanta, is based on a lotion that suffocates the lice, but it also contains a 5% concentration of benzyl alcohol that shocks the spiracles open. Phase 2 and phase 3 clinical trials conducted for Shionogi by the drug-testing company Global Health Associates of Miami compared use of Ulesfia to use of the lotion only in 250 children with head lice. A caregiver applied the lotions to the hair for 10 minutes at the beginning of the study and a week later. Company president Terri L. Meinking and her associates reported in Pediatric Dermatology that 91.2% of those using Ulesfia had no lice on Day 8 and 75.6% had none on Day 14. Among those using only the lotion, 27.9% had no lice at Day 8 and 15.5% had none on Day 14. Irritation of the application site was the most commonly reported side effect, affecting 2.3% of users.
"Because benzyl alcohol lotion kills by suffocation, resistance should not be an issue," Meinking said in a statement.
-- Thomas H. Maugh II