Nits. View of nits (head louse eggs) in human hair. The nits are the small whitish blobs. The human head louse (Pediculus humanus capitis) is a small, wingless insect that sucks blood from the scalp and lays its eggs on hairs (pediculosis). The lice leave bites that develop into intensely itchy spots, provoking scratching. Scratching the bites can lead to inflammation and infection of the skin. Head lice mostly affect children, and are not necessarily a sign of poor hygiene. They can be killed by treating the hair with lotions or shampoos containing malathion or carbaryl. The dead nits and lice are then removed with a fine- toothed comb.