Infestation by head lice (pediculosis capitis) is very common in children both in industrialized and in developing countries. Children in developing countries often carry very heavy infestations, in contrast to industrialized countries were most children carry only a few lice. These makes that the diagnosis can be easily missed. In addition, very few studies have addressed the accuracy of diagnosis methods for pediculosis capitis. In a recent study published in the Archives of Dermatology, a group of researchers from Germany compared two diagnostic methods in a group of 304 children aged 6 to 12. Every child was examined first by visual inspection, and after that a second investigator, blinded on the results of the inspection, used a wet combing method after application of a conditioner. The investigator combed from roots to ends with a fine-toothed comb, and wiped on white sanitary paper to detect any lice, egg, or nit. Visual inspection was superior to wet combing with regard to the detection of eggs or nits (sensitivity, 86.1% vs. 68.4%). However, visual inspection underestimated the true prevalence of active infestation (presence of lice) by a factor of 3.5, because wet combing had a significantly higher sensitivity for detecting active infestations, correctly identifying them in 90.5 percent of the children (vs. 28.6 percent for visual inspections). As the presence of eggs or nits is only indicative of past infestation, and the presence of lice of active infestation, this study shows that wet combing should be the method of choice for making a diagnosis of active pediculosis capitis infestation. (more…)