Head lice combing. Special comb being used by a mother to remove dead head lice and nits from her daughter's hair. Head lice (Pediculus humanus capitis) are small, wingless insects that suck blood from the scalp of humans and lay eggs (nits) on hairs. The lice leave itchy bites. Scratching of the bites can cause inflammation and infection of the skin. Head lice mostly affect children and are transmitted via direct contact. They can be killed by using medicated lotions or shampoos. The dead lice and nits are then removed with a special fine-toothed comb.