Overview

Lice are tiny, wingless, parasitic insects that feed on your blood. Lice are easily spread — especially by schoolchildren — through close personal contact and by sharing belongings.

Several types of lice exist:

  • Head lice. These lice develop on your scalp. They're easiest to see at the nape of your neck and over your ears.
  • Body lice. These lice live in clothing and on bedding and move onto your skin to feed. Body lice most often affect people who aren't able to bathe or launder clothing regularly, such as homeless or transient individuals.
  • Pubic lice. Commonly called crabs, these lice occur on the skin and hair of your pubic area and, less frequently, on coarse body hair, such as chest hair, eyebrows or eyelashes.

You or your child can have good personal hygiene habits and still get lice. Unless treated properly, this condition can become a recurring problem.

Symptoms

Signs and symptoms of lice include:

  • Intense itching.
  • Tickling feeling from movement of hair.
  • Lice on your scalp, body, clothing, or pubic or other body hair. Adult lice may be about the size of a sesame seed or slightly larger.
  • Lice eggs (nits) on hair shafts. Nits resemble tiny pussy willow buds. Nits can be mistaken for dandruff, but unlike dandruff, they can't be easily brushed out of hair.
  • Small red bumps on the scalp, neck and shoulders.

When to see a doctor

Usually you can get rid of lice by taking self-care steps that include using nonprescription shampoo that's specifically formulated to kill lice.

However, see your doctor if:

  • Nonprescription shampoo doesn't kill the lice — your doctor can prescribe a stronger, prescription shampoo
  • You're pregnant — don't use any anti-lice shampoo until you talk to your doctor
  • You have any infected hives or skin abrasions from scratching

Causes

You can get lice by coming into contact with either lice or their eggs. Eggs hatch in about one week. Lice can't fly or walk on the ground. They spread through:

  • Head-to-head or body-to-body contact. This may occur as children or family members play or interact closely.
  • Proximity of stored belongings. Storing infested clothing in closets, in lockers or on side-by-side hooks at school, or storing personal items such as pillows, blankets, combs and stuffed toys in proximity at home can permit lice to spread.
  • Items shared among friends or family members. These may include clothing, headphones, brushes, combs, hair decorations, towels, blankets, pillows and stuffed toys.
  • Contact with contaminated furniture. Lying on a bed or sitting in overstuffed, cloth-covered furniture recently used by someone with lice can spread them. Lice can live for one to two days off the body.
  • Sexual contact. Pubic lice usually spread through sexual contact and most commonly affect adults. Pubic lice found on children may be a sign of sexual exposure or abuse.

Prevention

It's difficult to prevent the spread of head lice among children in child care and school settings. There's so much close contact among children and their belongings that lice can spread easily. It's no reflection on your hygiene habits or those of your children, and it's not a failure on your part as a parent if your child gets head lice.

Some over-the-counter products claim to repel lice, but more scientific research is needed to prove their safety and effectiveness.

A number of small studies have shown that ingredients in some of these products — mostly plant oils such as coconut, olive, rosemary and tea tree — may work to repel lice. However, these products are classified as "natural" so they aren't regulated by the Food and Drug Administration (FDA), and their safety and effectiveness haven't been tested to FDA standards.

Until more research proves the effectiveness of head lice prevention products, the best approach is simply to take thorough steps to get rid of the lice — and their eggs — so that you don't have more lice to deal with.

  • Ask your child to avoid head-to-head contact with classmates during play and other activities.
  • Instruct your child not to share personal belongings such as hats, scarves, coats, combs, brushes, hair accessories and headphones.
  • Instruct your child to avoid shared spaces where hats and clothing from more than one student are hung on a common hook or kept in a locker.

However, it's not realistic to expect that you and your child can eliminate all the types of contact that may result in the spread of lice.

Your child may have nits in his or her hair but not necessarily develop a case of head lice. Some nits are empty eggs. However, nits that are found within 1/4 inch (6.4 millimeters) of the scalp should be treated — even if you find only one — to prevent the possibility of hatching. Nits that are farther away from the scalp are probably from an old infestation, but should be removed to prevent a recurrence.

March 28, 2015
References
  1. Head lice: Frequently asked questions. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/head/gen_info/faqs.html. Accessed March 9, 2015.
  2. Body lice: Frequently asked questions. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/body/gen_info/faqs.html. Accessed March 10, 2015.
  3. Pubic "crab" lice: Frequently asked questions. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/pubic/gen_info/faqs.html. Accessed March 10, 2015.
  4. Goldstein AO, et al. Pediculosis capitis. http://www.uptodate.com/home. Accessed March 10, 2015.
  5. Goldstein AO, et al. Pediculosis pubis and pediculosis ciliaris. http://www.uptodate.com/home. Accessed March 10, 2015.
  6. Head lice: Treatment. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/head/treatment.html. Accessed March 10, 2015.
  7. Body lice: Treatment. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/body/treatment.html. Accessed March 10, 2015.
  8. Pubic "crab" lice: Treatment. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/lice/pubic/treatment.html. Accessed March 10, 2015.
  9. Hoecker JL (expert opinion). Mayo Clinic, Rochester, Minn. March 12, 2015.