NICE CKS on head lice
Head lice (Pediculus humanus capitis) are parasitic insects that infest the hairs of the human head and feed on blood from the scalp. Head lice infestation is known as pediculosis capitis. The severity of infestation varies from a few lice (less than 10) to more than 1000 in severe cases, but a typical infestation might have about 30 lice per head. If left untreated, head lice infestation may persist for long periods. This summary covers how to manage patients with head lice, including a number of treatment options and additional information.