Summary: We usually notice the presence of head lice when dandruff-like flakes begin appearing at the base of the neck and behind the ears of children.
Head lice, also called Pediculosis, are tiny wingless insects that live on human heads and feed on their blood. The adult louse, about the size of a sesame seed, can be found on the scalp and, on rare occasions, on eyebrows or eyelashes. They are especially noticable at the neckline and behind the ears.
The eggs of the Head louse, called nits, may appear to look like dandruff flakes, but they don't shake off like dandruff and they are not removed by brushing. The tiny yellow, tan, or brown nit is attached to the hair shaft very close to the surface of the skin where scalp temperatures help in the incubation. It is the presence of nits that usually alerts us to the fact that lice are present.
Head lice are very common, being very contagious and spreading easily, especially among young children and their families. There is no reliable data on how many people get head lice in the United States each year, but it is known that girls get head lice more often than boys and women more often than men, probably due to more frequent head to head contact. It is also known that African-Americans rarely get head lice. This is believed to be due to the louse's preference for the shape and width of the hair shaft of other races. There are no diseases associated with having head lice and it is known that personal hygiene has nothing to do with getting head lice.
Lice feed every four to six hours, but can go without a blood meal for up to three days. Louse bites can cause itchy and inflamed scalps leading to infection. Symptoms include a tickling sensation on the head, frequent itching and scores resulting from scratching.