Head Lice
Condition
(Pediculosis)
Definition
Head lice are tiny insect-like animals called arthropods. They can live on the head and cause itching. Head lice can also live in the eyebrows, eyelashes, and beard. However, other lice such as crab lice (pubic lice) can also infest these areas. Treatment can get rid of lice.
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Causes
Head lice is spread by head-to-head or hair-to-hair contact. It can also be spread by sharing combs, brushes, hats, and other personal items.
Risk Factors
Head lice are more common in young children.
Things that may raise the risk of head lice are:
- Sharing combs, brushes, hats, and other personal items
- Head-to-head or hair-to-hair contact with people who may have lice
Symptoms
Some people with head lice do not have any symptoms.
When symptoms do occur, they may include:
- Itchiness
- A crawling feeling on the scalp
- Skin breaks and possible infection caused by scratching
Diagnosis
The doctor will ask about symptoms and past health. A physical exam will be done. The head and scalp will be examined for lice and lice eggs (nits).
Do not self-diagnose and self-treat head lice. Some treatments can cause irritation. They should only be used by people with lice.
Treatment
Treating head lice involves removing eggs and killing lice so that they cannot continue to lay eggs. Treatment may be difficult. In some regions, lice have become resistant to many commonly used medicines. Some experts advise treatment only when live adult lice are seen.
Methods include:
- Applying over-the-counter shampoo with permethrin. Retreatment at 7 to 10 days is often needed to kill any lice that hatch from unremoved eggs.
- Removing lice on the eyelashes, which may be difficult. Tweezers can be used to pick them off. Vaseline may be used to coat the eyelashes and kill the lice.
- Removing eggs with specially designed combs. Eggs stick firmly to hair.
Prevention
To help prevent outbreaks of head lice:
- Watch for signs of head lice such as frequent head scratching.
- Do not share combs, brushes, hats, or other personal items with people who may have lice.
- Avoid close personal contact with people who may have lice.
- If you or your children have head lice:
- Thoroughly wash and dry combs, brushes, hats, clothing, bedding, and stuffed animals with hot water.
- Vacuum carpeting and car seats.
- Items that cannot be washed with hot water should be:
- Dry cleaned, or
- Sealed in a plastic bag for 2 weeks.
- Check all family members for lice and eggs at least once a week. Treat if needed. Some family members may share a bed with a person with head lice. If so, consider treating them even if no head lice are seen.
Over-the-Counter Medication
Most cases of head lice can be treated with over-the-counter preparations. Herbal treatments with coconut oil and anise may also be effective.
Prescription Medication
Prescription creams or lotions may be prescribed to treat head lice. These include:
- Benzyl alcohol lotion
- Ivermectin lotion
- Malathion lotion
- Abametapir
Lindane can affect the brain and nervous system. It carries a black box warning about serious side effects. Many doctors do not recommend it. Other treatments are advised first.
Centers for Disease Control and Prevention
Nemours Kids Health
CANADIAN RESOURCES
Caring for Kids—Canadian Paediatric Society
Health Canada
Centers for Disease Control and Prevention
Nemours Kids Health
CANADIAN RESOURCES
Caring for Kids—Canadian Paediatric Society
Health Canada
References
- Head lice. American Academy of Dermatology website. Available at: https://www.aad.org/public/diseases/contagious-skin-diseases/head-lice. Accessed January 29, 2021.
- Head lice. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T116514/Head-lice . Accessed January 29, 2021.
- Lindane. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T233229/Lindane . Accessed January 29, 2021.
- Parasites—lice—head lice. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/parasites/lice/head. Accessed January 29, 2021.
- 11/26/2012 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T116514/Head-lice : Pariser D, Meinking T, Bell M, et al. Topical 0.5% ivermectin lotion for treatment of head lice. N Engl J Med. 2012;367(18):1687-1693.
Contributors
- David L. Horn, MD, FACP
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