Pests in Gardens and Landscapes: Quick Tips

Head Lice

Published   4/19

PDF Spanish version of this Pest Alert

Read more on this topic

Stages in the development of head lice.

Stages in the development of head lice.

Eggs (nits) of head lice on human hairs.

Eggs (nits) of head lice on human hairs.

Anyone can get head lice, but children are more prone to infestations because they play closely with one another. Head lice are usually spread through direct head-to-head contact and more rarely from contact with infested hats or combs. Head lice are not known to transmit any infectious diseases, but infestations can cause discomfort, anxiety, and embarrassment. Control lice by using a combination of treatment with an effective insecticide (to kill live lice) and combing to remove eggs (nits).

Head lice facts

  • Head lice cannot hop, fly, or jump; they crawl.
  • They can only survive off a human head for about 1 or 2 days.
  • Head lice cannot live on family pets.
  • Nits more than 1/4 inch from the scalp are probably dead or have already hatched.

What should I look for?

  • Eggs glued to the hair near the scalp. Developing eggs are dark in color, but white after hatching
  • Adult head lice are about the size of a sesame seed and crawl rapidly.
  • Some infestations may cause intense scratching on the back of the head or neck, although not everyone has this symptom.

How do I manage a head lice infestation?

  • Remove eggs (nits) by combing hair with a specially designed metal comb. This is key to successful control, regardless of the any insecticide treatment used.
    • Comb wet, conditioned hair.
    • Repeat daily as long as you find live lice or eggs within 1/4 inch of the scalp
  • Remove lice and eggs from any infested areas.
    • Wash clothing and bedding in hot water and dry in a hot dryer.
    • Freeze items like headphones, hats, and bike helmets in plastic bags for at least 10 hours.
    • Clean stuffed animals, car seats, and other objects that might have come in contact with the infested person’s head. Vacuum carpets and upholstery.
    • Pesticide sprays are not necessary.
  • Avoid head-to-head contact with the infested person.
    • Inform anyone who has been in close contact in the recent past.
    • It’s not necessary to keep children home from school unless an extreme infestation is found.
  • Consider treating infested scalps with a head louse insecticidal product.
    • Effective, less toxic products contain dimethicone, benzyl alcohol, or spinosad.
    • Avoid products containing permethrin, malathion, pyrethrin, and lindane, since head lice are often resistant to them (reducing their effectiveness). Lindane and malathion are also more toxic to humans.
  • Check heads and remove eggs daily until infestation is gone.
    • Follow with weekly head checks to detect reinfestation.
  • Some people never itch so itching is not a reliable way to tell if someone is infested.

Read more about Head Lice.

Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal.

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2019 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /QT/headlicecard.html?srcPage=QT%2Fheadlicecard.html revised: May 14, 2019. Contact webmaster.