Back

Head Lice

(Pediculosis)

Definition

Head lice are tiny insect-like animals called arthropods that may live on the head and cause itching. ("Lice" is plural; the singular is "louse.") Head lice may also live in the eyebrows, eyelashes, and beard. However, sometimes infestations in these areas are from a related species called pubic lice.
Head Lice
Nucleus factsheet image
Copyright © Nucleus Medical Media, Inc.

Causes

Head lice spread by personal contact and by sharing combs, brushes, hats, and other personal items.

Risk Factors

This condition is more common in young children.
Factors that may increase the risk of lice include:

Symptoms

Some people with head lice do not have any symptoms.
When symptoms do occur, they may include:

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. Your 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 and should only be used by people who have the infestation.

Treatment

Treating head lice involves removing eggs and killing lice so that they can't continue to lay eggs. Treatment may be difficult. In some regions, lice have become resistant to many commonly used medications. Some experts recommend that treatment be given only when live adult lice are seen.
Methods include:

Over-the-Counter Medication

Most cases of head lice can be treated with over-the-counter preparations. However, there is increasing resistance to the medications permethrin and pyrethrin in the United States. There are other treatments that may be effective, such as herbal remedies that contain coconut oil and anise.

Prescription Medication

Prescription creams or lotions may be prescribed to treat head lice.
In certain cases, your doctor may prescribe lindane. Lindane is neurotoxic and carries a black box warning. Follow the instructions carefully. It should only be prescribed to patients who are unable to take other medications or who have not responded to them. According to the Food and Drug Administration’s warning, lindane can rarely cause serious side effects, including seizure and death. Those especially susceptible are infants, the elderly, children and adults weighing under 110 lbs, and individuals with other skin conditions. Lindane is toxic and should not be overused. Patients are given small amounts (1-2 ounces) of the shampoo or lotion and instructed to apply a thin layer and not to reapply. For more information, visit the US Food and Drug Administration website .

Prevention

Lice are common, especially in children. To prevent outbreaks of head lice:

RESOURCES

Centers for Disease Control and Prevention http://www.cdc.gov

Kids Health—Nemours Foundation http://kidshealth.org

CANADIAN RESOURCES

Caring for Kids—Canadian Paediatric Society http://www.caringforkids.cps.ca

Health Canada http://www.hc-sc.gc.ca

References

Lindane shampoo and lindane lotion. US Food and Drug Administration website. Available at: http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm110452.htm. Updated June 18, 2009. Accessed January 15, 2015.

Medication guide lindane lotion. US Food and Drug Administration website. Available at: http://www.fda.gov/downloads/Drugs/DrugSafety/UCM133687.pdf. Updated August 2007. Accessed January 15, 2015.

Medication guide lindane shampoo. US Food and Drug Administration website. Available at: http://www.fda.gov/downloads/Drugs/DrugSafety/UCM133688.pdf. Updated August 2007. Accessed January 15, 2015.

Head lice. American Academy of Dermatology website. Available at: https://www.aad.org/dermatology-a-to-z/diseases-and-treatments/e---h/head-lice. Accessed January 15, 2015.

Revised lindane lotion label. US Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda%5Fdocs/label/2003/006309lotionlbl.pdf. Accessed January 15, 2015.

Revised lindane shampoo label. US Food and Drug Administration website. Available at: http://www.accessdata.fda.gov/drugsatfda%5Fdocs/label/2003/006309shampoolbl.pdf. Accessed January 15, 2015.

Roberts RJ. Clinical practice. Head lice. N Engl J Med. 2002;347(17):1381-1382.

12/14/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Burgess IF, Brunton ER, Burgess NA. Clinical trial showing superiority of a coconut and anise spray over permethrin 0.43% lotion for head louse infestation, ISRCTN96469780. Eur J Pediatr. 2010;169(1):55-62.

11/26/2012 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Pariser D, Meinking T, Bell M, et al. Topical 0.5% Ivermectin Lotion for Treatment of Head Lice. N Engl J Med. 2012; 367:1687.

Revision Information