[Metal microchanelled fine-toothed comb use in the diagnosis of pediculosis].

BACKGROUND Methods for the diagnosis of Pediculus humanus var. capitis are controversial and most studies are based on direct visual exam. OBJECTIVE The objective of this study was to compare the diagnosis efficacy of both direct visual exam and the use of a metal microchanelled fine-toothed comb. METHODS 946 children and teenagers 4 to 19 years of age were examined. Each individual's hair was examined twice to determine whether there was infestation by lice or nits, through direct visual exam and the use of a metal microchanelled fine-toothed comb. RESULTS The visual diagnosis detected infestation in 30.7% of the cases, while the metal comb detected infestation in 51.5%. Females were the most affected. The forms of parasites detected through direct visual exam were: only lice (adults and/or nymphs) 1.4%, only live nits 64.8% and live nits and lice, 33.8%; with the metal comb the percentages were 6.4%, 23.6% and 70%, respectively. The average time to find a louse was 57 seconds with the fine-toothed comb and 116.4 seconds through the direct visual exam. CONCLUSIONS Diagnosis with the microchanelled fine-toothed comb is twice as fast and 3.6 times more efficient than through direct visual exam.The direct visual exam detects non-active, past infestations, and underestimates active ones.