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Head Lice (Pediculosis)

What are head lice?

  • Lice are tiny insects that live on and crawl through the hair. They are gray, brown, or black and can be difficult to see. They do not leave the human host on their own – they must be physically dislodged. They do not infest pets, furniture, carpeting or toys. Head lice live only on the heads of their human hosts.
  • Lice need human blood to survive and most will die within 24 hours if they can not find a "meal".
  • Lice lay eggs (nits) on the hair close to the scalp. It takes about 6 days for the nits to hatch. Nits have to be on the hair near the scalp in order to hatch. Nits which have been dislodged will not hatch in the environment.
  • Nits are easier to see than lice. Nits are oval shaped and most often can been seen in the hair behind the ears or near the neck.
  • Head lice themselves are not a health hazard or a sign of uncleanliness, and are not responsible for the spread of any disease.

What are the symptoms?

Itching of the scalp is the most common symptom. Scratching can lead to skin sores and skin infections.

How are head lice spread?

  • Most often, by head-to-head contact with another person who has lice.
  • By wearing another person's hat or clothing, by using another person's comb, brush, or bedding.
  • More rarely, by placing clothing worn by someone who has lice in a shared clothing storage compartment, locker, or a cloak room.
  • Not by pets.

How can you prevent head lice outbreaks?

  • Check your children's hair weekly for lice or nits.
  • Treat the hair right away if you find them.
  • Do not share combs, brushes, towels, bedding, hats or clothing.
  • Provide separate storage areas for each person's clothing and other personal articles. Put personal articles in individual bins or sacks.
  • Avoid sharing costumes, and headgear/helmets. Use disposable shower caps or inexpensive liners when headgear/helmets must be worn by different children.
  • Assign sleeping mats and bedding to only one person and store these separately.

Steps for eliminating lice and nits

Lice and nits are most effectively removed by using a combination of combing and lice treatments. There are both insecticidal and non-toxic lice treatments available over the counter.

The most important step in successfully treating lice is thorough, careful combing of the hair for lice and nits at least daily for 14 days. It is important to use an effective lice comb for this step (see below).

How do I comb hair to remove lice and nits?

  • Allow yourself enough time to do a good job. It may take as long as an hour if the hair is long and thick. Work in good light.
  • Apply one of the lice treatments as described below.
  • Be sure to use an effective, nit-removal comb such as Licemeister® or LiceOut®.
  • Place a towel between the hair and shoulders of the person who has head lice.
  • Part the hair into four sections and pin the hair with clips to prepare it for combing.
  • Starting with one section, select a small area of the section that is about 1 inch square. Start at the scalp and pull the comb all the way through to the end of the strands of hair.
  • If nits remain attached to the hair shaft, comb through the hair strands again.
  • After each comb-through, dip the lice comb in hot water and wipe it with a paper towel.
  • Continue combing until all sections are done.
  • Wash the towel and clothes the person wore during the combing as described below.
  • Wash the comb in extra-hot (128° F) soapy water for at least 10 minutes.
  • Wash hands completely when done.

What chemical-free treatments are recommended?

  • Chemical-free treatments can be used as often as needed. They do not kill lice or nits. They slow down the lice and make it easier to comb them out.
  • These treatments include coating the hair with one of the following:

    Water-based products such as LiceOut®; or
    HairClean 1-2-3®. Follow instructions on the box.
    • Apply thickly to hair.
    • Cover hair with disposable shower cap; leave in place for at least 30 minutes.
    • Follow instructions for lice and nit removal using an effective lice comb. Do not use these treatments at the same time the chemical treatment is used.

About chemical treatment: Nix®

  • Although it is the most effective of the chemical treatments, it will not kill lice that have become resistant. It can be purchased without a prescription.
  • Wash the hair with a mild shampoo that contains
    NO CONDITIONER, such as baby shampoo.
  • Following the instructions on the box, apply Nix®.
  • Comb the hair with a clean lice comb to remove the nits. Dry hair as usual.
  • Repeat Nix® treatment in 7 days.
  • REMEMBER: Since lice may be resistant to Nix® and other pesticides, you must perform daily nit combing for 14 days after using these products to assure complete removal of lice and nits.

CAUTION!

  • Do not use Nix® when open sores are present.
  • Do not use Nix® on children who are less than 2 months of age.
  • Pregnant/breastfeeding women should consult their health care provider before using Nix®.
  • Never mix Nix® with other lice treatments.
  • DO NOT USE any other creme rinse, shampoo containing creme rinse, hair spray, mousses, gels, mayonnaise, or vinegar on the hair for at least 1 week AFTER using Nix®, because they may weaken the action of Nix®.
  • Chlorine in pool water may also deactivate Nix® leading to some treatment failures.
  • Never use Nix® on eyebrows and eyelashes. Apply petrolatum jelly for a few days and pluck off nits with fingers.
  • Never use Nix® more often than recommended. It is an insecticide and can be poisonous if used improperly.

What else do I need to do?

In addition to the steps listed above, these actions may help control the spread or re-infestation of head lice in a household.

  • Check other household members for lice. Treat other family members who have lice. Do not treat someone if you do not see lice or nits in their hair.
  • Notify your child's school and child care program if your child has lice.
  • Wash all combs or brushes used by the person in extra-hot (128.3ºF) soapy water for at least 10 minutes.
  • Wash all clothing (including coats, hats, scarves) and bedding used by the infested person in the last 2 days prior to the treatment.

To wash these items, do ONE of the following:

  • Wash in extra-hot or heat dry the item at temperatures more than 128.3° F for at least 5 minutes.
  • Dry clean the item.
  • Pack non-washable items in a sealed plastic bag for 2 weeks to eliminate the risk from lice that may have been dislodged onto those items.
  • You may vacuum upholstered furniture, carpets, bicycle helmets, sports helmets, and upholstered car seats. Change the vacuum cleaner bag after use and place it in a sealed plastic bag and put the bag in the outside garbage.
  • Do not use lice sprays! They may cause toxic or allergic reactions.

What if the lice come back or the treatment fails to work?

  • If lice come back, it is usually because nits or newly hatched lice were not removed with the first treatments.
  • Follow the combing instructions as described.
  • You may use the chemical free treatments as often as needed.
  • You may use Nix® again after 7 days have passed since the last application of Nix®.
  • No matter which treatment you use, the most important thing is to comb out the lice and nits completely.

Additional information

learn more
Head Lice fact sheet in Spanish / Piojos en la cabeza (Pediculosis)
Los piojos de la cabeza en si no son un peligro de salud o una muestra de mal hygiene y no son responsables por la propagación de enfermedades.