Head lice : causes, symptoms, diagnosis, treatment, complications, risk ...
The head louse is a tiny, wingless parasitic insect that lives among human hairs and feeds on tiny amounts of blood drawn from the scalp. Lice (the plural of louse) are a very common problem, especially for kids. They're contagious, annoying, and sometimes tough to get rid of.
But while they're frustrating to deal with, lice aren't dangerous. They don't spread disease, although their bites can make a child's scalp itchy and irritated, and scratching can lead to infection.
It's best to treat head lice quickly once they're found because they can spread easily from person to person.