Facts About Hair Lice

Head lice are small parasitic insects that live among human hairs. The insects feed on small amounts of blood drawn from the scalp causing itchiness and inflammation from the bites. Head lice, known also as pediculosis, are a common problem among children ages 3 to 12. Various signs of the problem can lead to treatment to rid scalps of the pesky critters.

The Facts

• Head lice can survive on a human host for about 30 days and cannot typically survive off the host longer than 24 hours. Female louse (singular of the word "lice") lays three to five eggs a day and the eggs hatch in seven to 10 days. It takes another seven to 10 days for the louse to mature and lay eggs in the scalp of a human host. Head lice are more common among girls than boys.

  The insect’s bite leaves the scalp feeling irritated, causing itching and inflammation. Worse cases lead to skin irritation and infection.

How Head Lice Spread

• Lice are contagious and can be spread through direct contact of the hair of a person with a lice infestation on their scalp. Lice also can spread by sharing brushes, towels, hats and other items from a person with lice. Though it’s not as common, head lice also can be spread by sharing pillows, headrests and furniture.

Signs and Symptoms

• Lice are very small and sometimes can be difficult to see with the naked eye, though not impossible. To properly see the scalp, part the hair into small sections and look at the scalp closely under a bright light. If you are unsure if you or your child has lice, consult a doctor who has experience in identifying the insects.

  Mature lice lay eggs on the hair shaft close to the skin’s surface on the scalp. Lice eggs, called nits, resemble tiny yellow, tan or brown dots before they hatch and often are mistaken for dandruff. Different from dandruff, lice eggs cannot be removed by brushing your hair with a common brush or by shaking off the eggs from your hair.

  An adult louse is no bigger than a sesame seed and is grayish-white or tan in color. Baby lice, called nymphs, are smaller and become adults in one to two weeks after hatching. It is more common to see nits than live lice crawling on the infested scalp. In extreme cases of lice infestation, however, live lice may be more visible.

  Itching and subsequent scratching usually follow after a louse bite on the scalp. Itching may not always occur, however, and depends on the sensitivity of the scalp. In children with nonsensitive scalps, they may complain of feeling the sensation of the crawling lice.

  Small, red bumps or sores may develop from excessive scratching. In some cases, the irritation caused by scratching may cause a bacterial infection, resulting in tender skin and swollen lymph nodes.

Treatment

• Doctors generally recommend over the counter medicated shampoo, creams and lotions to kill lice. If a more extensive treatment is necessary, doctors may recommend prescription medicine. Most medications are successful in killing the lice though itching may continue a few days after treatment.

  Doctors recommend products that have insecticides and it is important to follow the directions carefully for optimum results. After treatment, your doctor may suggest combing out the nits and dead lice with a fine-toothed comb and repeating the treatment in seven to 10 days to kill any newly hatched nits.

Prevention

• Wash in hot water all of your bed linens, stuffed animals and clothing recently worn by someone with a lice infestation. Vacuum carpets and upholstered furniture as an added safety precaution. Soak all hairbrushes, combs, headbands and other items in medicated shampoo or rubbing alcohol or if possible, throw these items away.

  Inform your children to avoid sharing with classmates their hairbrushes or headbands. Also ask them to avoid head-to-head contact at school in sports activities.

  Check with your child’s school authorities to see if any children have recently been treated for head lice. If you discover your child has lice, inform the school’s staff to prevent spreading the insects.