By GreatSchools Staff
Every year countless kids are exposed to Pediculus humanus capitis, the human head louse. Most schools have a no-nits policy, which means students with any signs of infestation must stay home. Thus schools lose money whenever lice strike. If one in every 10 children in the United States gets lice at some point, MedicineNet estimates that the yearly cost of lice is $1 billion.
But first things first: How do you identify lice, and where do you look for them? Expect to find nits — or yellowish, oval eggs that resemble dandruff or scabs — on the hair an inch or two above the scalp. They're usually concentrated behind the ears and in the hairline just above the neck. Eggs take about eight or nine days to hatch, and newly hatched lice are called nymphs. Often too small to be visible to the naked eye, nymphs mature to the adult stage within 9 to 12 days. Fully grown lice are tan to grayish-white, about the size of a sesame seed, and six-legged with sharp, hook-like claws they use to attach themselves to hair. They feed on blood and can survive on a person's head for up to a month.
For answers to commonly asked questions about lice, check out this fact sheet from the Centers for Disease Control and Prevention. For those with questions about the nature of an infestation, the Harvard School of Public Health offers free head louse evaluation by mail.
Next: Nit-picking »
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