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.
Chile; lice infestations; Pediculus capitis; scalp dermatoses
