The head louse, or Pediculus Humanus Capitis, is a parasitic insect that can be found on the head, eyebrows, and eyelashes of people. Head lice feed on human blood several time a day and live close to the human scalp. Head lice are not known to spread disease.
Head lice are small and about the size and flattened shape of a sesame seed. They are naturally gray in color but are known to take on the color of their current host’s hair. They also lay eggs, called ‘nits‘, that are cemented to hair shafts.
Symptoms include intense itching accompanied by tickling, feelings of movement in the hair, irritability, and finally, sores on the head caused by excessive scratching.
Head lice are parasites that feed off human blood; they survive on several meals a day. The open wounds that they create cause sores on the scalp. These sores can develop into infections, especially in a person with a blood-related medical condition.
Head lice are found worldwide. In the United States, infestation with head lice is most common among pre-school children attending child care, elementary school children, and the household members of infested children. Although reliable data on how many people in the United States get head lice each year are not available, an estimated 6 million to 12 million infestations occur each year in the United States among children 3 to 11 years of age.
Head lice move by crawling; they cannot hop or fly. Head lice are spread by direct contact with the hair of an infested person. Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk. Spread by contact with clothing (such as hats, scarves, coats) or other personal items (such as combs, brushes, or towels) used by an infested person is uncommon. Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.
Head-to-head contact with an already infested person is the most common way to get head lice. Head-to-head contact is common during play at school, at home, and elsewhere (sports activities, playground, slumber parties, camp).
Although uncommon, head lice can be spread by sharing clothing or belongings. This happens when lice crawl, or nits attached to shed hair hatch, and get on the shared clothing or belongings.
Examples include: sharing clothing (hats, scarves, coats, sports uniforms) or articles (hair ribbons, barrettes, combs, brushes, towels, stuffed animals) recently worn or used by an infested person; or lying on a bed, couch, pillow, or carpet that has recently been in contact with an infested person. Dogs, cats, and other pets do not play a role in the spread of head lice.
Lice and nits are spread mostly through physical head to head contact or in some cases, proximity to personal items that come into contact with an infected person, such as hats, combs or pillows. However, lice is in no way a reflection of poor hygiene.
Head lice should not be considered as a medical or public health hazard. Head lice are not known to spread disease. Head lice can be an annoyance because their presence may cause itching and loss of sleep. Sometimes the itching can lead to excessive scratching that can sometimes increase the chance of a secondary skin infection.
Head lice are spread most commonly by direct contact with the hair of an infested person. Spread by contact with inanimate objects and personal belongings may occur but is very uncommon. Head lice claws are specially adapted for holding onto human hair. Head lice would have difficulty attaching firmly to smooth or slippery surfaces like plastic, metal, polished synthetic leathers, and other similar materials.
Head lice and their eggs (nits) soon perish if separated from their human host. Adult head lice can live only a day or so off the human head without blood for feeding. Nymphs (young head lice) can live only for several hours without feeding on a human. Nits (head lice eggs) generally die within a week away from their human host and cannot hatch at a temperature lower than that close to the human scalp. For these reasons, the risk of transmission of head lice from a wig or other hairpiece is extremely small, particularly if the wig or hairpiece has not been worn within the preceding 48 hours by someone who is actively infested with live head lice.
Data show that head lice can survive under water for several hours but are unlikely to be spread by the water in a swimming pool. Head lice have been seen to hold tightly to human hair and not let go when submerged under water. Chlorine levels found in pool water do not kill head lice.
Head lice may be spread by sharing towels or other items that have been in contact with an infested person’s hair, although such spread is uncommon. Children should be taught not to share towels, hair brushes, and similar items either at poolside or in the changing room.
No, swimming in a pool can not stop nor prevent the spread of head lice.
No, unfortunately, dying your hair does not stop nor prevent the spread of head lice.
No, unfortunately, flat ironing your hair does not stop nor prevent the spread of head lice.