Malathion for head lice and scabies: treatment and safety considerations.

Malathion is an under-recognized and under-utilized therapy for head lice and scabies largely due to misperceptions about its safety profile. Specifically, its pure form as it exists in pharmaceutical preparations is non-toxic to humans in the low doses available. While labeled for ages six and up, recent studies showed no cholinesterase inhibition in head lice patients aged two-to-six treated with malathion. Flammability of malathion in isopropyl alcohol has reportedly resulted in human injury once in over one million prescriptions filled. Recent efficacy studies of malathion in United States (U.S.) head lice demonstrate efficacy rates of 97-98%. In the present era of permethrin and lindane resistance to head lice, malathion is a first-line option. For scabies, it is a reasonable alternative to permethrin 5% cream, especially when treatment of the scalp or hairy areas is desired.