Head lice eggs -- called nits -- are only a millimeter long (sometimes smaller) and shaped like tear-drops. Unlike dandruff, these little buggers clamp on tight to the hair shaft. They only come off with encouragement. Sometimes, you literally have to pull them off the hair with your fingernail.
Seeing nits isn't enough reason to run out and buy lice shampoo. Nits only tell you that head lice used to be there. They don't tell you if head lice are present now. In fact, if the nits are more than half an inch away from the scalp, it's a good chance the nits are old and the infestation isn't active anymore.
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