Comparison of pediculicidal and ovicidal effects of two pyrethrin-piperonyl-butoxide agents.

A pyrethrin-piperonyl-butoxide shampoo was compared with a similarly formulated lotion for their pediculicidal and ovicidal effects against head lice. Forty children with active Pediculus humanus capitis infestation were randomly assigned to one of two groups for a single treatment with either the shampoo or the lotion. An average of ten nits were taken from each patient both before and after treatment. These eggs were incubated for 14 days, the resulting lice counted, and their conditions noted. Lice recovered from the rinse water after treatment were also counted and observed. Although both products proved to be effective in killing lice, the shampoo had greater ovicidal efficacy, 50% versus 25% for the lotion, after adjustment for natural mortality of the ova.