Health Office » Head Lice Information

Head Lice Information


 -Head lice is a parasitic, wingless insect found on the head, eyebrows, and eyelashes. They are most commonly found on the scalp behind the ears, and at the base of the head. Head lice feed on human blood several times a day and have to live close to the human scalp. Head lice do not spread disease.

- Children ages 3-12 are most commonly affected.

-Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.

-Head lice move by crawling; they do not jump or fly. The lice hold to the hair tightly with hook-like claws.

-Head lice are spread by direct contact with the hair of an infested person. Spread by contact with clothing (hats, scarves, coats) or other personal items (combs, brushes, towel) used by an infested person is uncommon. It would be hard for the lice to be spread by helmets or headphones due to the hook-like claws that are specially adapted for holding onto the hair. It would be difficult attaching to surfaces like plastics, metal, etc. Avoid sharing these items to prevent the possibility of spreading lice.

-Lice are not passed on pets.

-Schools are not the most common places where head lice are spread, even though schools have been blamed in the past. Sleep-overs among friends and relatives are thought to be a common way they are passed home to home.

-Head lice infestations have been shown to have low contagion in classrooms.

-One of the biggest challenges in eliminating head lice is parents’ discomfort in communicating about the problem with other parents when they find head lice, so they are more easily passed back and forth among close friends and relatives.

-Only items that have been in contact with the head of the person with infestation in the 24-48 hours before treatment should be considered for cleaning. Washing, soaking, or drying items at temperatures greater than 130 degrees will kill stray lice or nits. For furniture, carpeting, fabric covered items, vacuuming is recommended.

-Head lice have 3 forms: the egg (nit), the nymph (immature lice), and the adult.

          >the eggs are laid at the base of the hair shaft near the scalp.

They usually take about 8-9 days to hatch. Eggs that are likely to hatch are usually located no more than ¼ inch from the base of the hair shaft; further than ¼ inch from the base may have already hatched or they are non-viable. This is hard to distinguish with the naked eye. Nit removal decreases the possibility of unnecessary re-treatment and hatching of viable eggs. Combing out the nits is time-consuming abut the most effective way to get rid of them.

>the nymph, immature louse, must feed on blood to survive. They mature into adults about 9-12 days after hatching from the nit.

>the adult lice is the size of a sesame seed; to survive the lice must feed on blood. They live about 30 days. An adult lice can lay 6-10 eggs a day.   They cannot live more than 24-48 hours if it falls off a person’s head.

-There are over the counter and prescription shampoos available for treatment; speak to your doctor regarding the best treatment option.

-Because of the use and overuse of head lice shampoos, head lice have become resistant to the products that once would kill them, so no head lice product is 100% effective, even if you follow the directions to the letter. That is why combing and nit removal is important!