News Details

Health Update: Head Lice

Health Update: Head Lice

Head lice (Pediculus humanus capitis) are parasites that are found on human heads. They spread from person to person by head-to-head contact through direct contact with the hair of an infected person. Head lice can also spread by personal contact or the sharing of combs, brushes, hats, and other clothing items. Although itching may be a sign of a lice infestation, frequently, individuals have no symptoms. Consider that although the most reliable sign of an infestation is the presence of a live louse or nymph, the presence of nits may be a sign that there is or has been an active infestation. Head lice infestation is very common, though the precise frequency of infections is unknown, estimates span from 6-12 million cases yearly. Those who come in close contact with someone who has head lice, or their contaminated clothing and other belongings, are at risk for acquiring head lice. Thus, it is easy for head lice to be transferred from one person to another. Head lice are a common problem with school-aged children. Preschool and elementary-school children (3-11 years of age) and their families are infected most often, and females contract head lice more often than males.

There are multitudes of ways to contract head lice:

  • Contact with an already infected person (common during play, school, or sports activities, and at school, home, slumber parties, or camp.)
  • Wearing infested clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons
  • Using infested combs, brushes, or towels
  • Lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with a person with lice (this risk is very low if more than 48 hours has passed since the exposure)

Keep in mind that getting a head lice infection has no correlation with personal hygiene. Anyone can become infested with head lice.

There are three forms of lice, the nit, the nymph, and the adult louse.

  • Nits are lice eggs. They are difficult to see and are often confused with dandruff or hair-spray droplets. Nits are found securely attached to the hair shaft. They are oval shaped, 2-3 mm in length and usually yellow to white in color. They traditionally take about a week to hatch.
  • The nit hatches into a baby louse called a nymph. It looks like an adult head louse but is smaller. Nymphs progress into adults about seven days after hatching. To live, the nymph must feed on human blood.
  • The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white in color. Females lay nits; they are usually larger than males. Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on human blood. If the louse falls off a person, it dies within 48 hours. Head lice are most regularly located on the scalp behind the ears and close to the neckline at the back of the neck. Head lice hold on to hair with hook-like claws that are found at the end of each of their six legs. They are rarely located on the body, eyelashes, or eyebrows.

Signs and symptoms include:

  • a tickling feeling of something moving in the hair · itching
  • sores on the head
  • sores on the head can sometimes become infected
  • irritability.

Head lice can be identified by looking closely through the hair and scalp for nits, nymphs, or adults. Locating a nymph or adult may be difficult because there are usually only a few of them, and they tend to move quickly. Nonetheless, the presence of nits close to the scalp confirms that a person is infested. If the nits are located more than ¼ inch from the scalp, the infestation is possibly an old one. If you are unsure the diagnosis should be made by a health care professional, school nurse, or a professional from the local health department.

For effective elimination of head lice, the infested individual, family members that are also infested, and the home must all be treated. Over-the-counter (OTC) or prescription medications are used to treat the affected people and their families. There are many brands and package directions should be followed.

Treating the whole house is essential. Follow these tips:

  • Machine wash all washable clothing and bed linens that the infested person touched during the two days before treatment to kill the lice and nits. Use the hot water cycle to wash clothes. Dry laundry using the hot cycle for at least 20 minutes.
  • Dry clean clothing that is not washable (coats, hats, scarves, etc.), or store all clothing, stuffed animals, comforters, etc., that cannot be washed or dry cleaned into a plastic bag and seal it for two weeks (by this time, any nits that have persisted will have hatched and the nymphs would die without a food source).
  • Soak combs and brushes for one hour in rubbing alcohol or wash with soap and hot water and then place in bag and leave in freezer for two days.
  • Vacuum the floor and furniture. Do not use fumigant sprays, these can be toxic if inhaled.

Although a person could develop a new infestation from being re-exposed to an infested individual, self-re-infestation is the most customary way for the infestation to reappear. The CDC recommends examining the individual for two to three weeks to confirm that there are no new nits or lice.