A 4-year-old male came home with a note from school that stated that head lice was being seen in the classroom and that he had been found with some nits in his hair (see Figure 41).
The school health department and local public health agency recommended over-the-counter Permethrin 1% to be used once and then again one week later.
Additionally, they recommended combing the wetted, shampooed hair with a nit comb nightly for 1-2 weeks after shampooing (see Figure 42 for an example, note the very fine teeth). Other control measures for the household were recommended such as treating the rest of the household members with the same medication and washing bedding, cleaning toy animals and other household items the child had contact with.
The parents noted on their physical exam of the child that he had several white spots stuck to the shaft of the hair but no obvious lice.
The work-up included the sibling and parents being inspected and they did not have any spots or lice noted by the parents.
The diagnosis of head lice was made. The child was treated according to the school’s recommendations and he had no recurrences of infestation.
Figure 44 – Photograph of head lice.
Figure 45 – Example of nit comb.
Pediculosis capitis or head lice is a common human infestation. Patients often are asymptomatic but itching is a common symptoms. Adult lice may be seen and nits (eggs) are found on the hair shafts.
Lice lay eggs within 3-4 mm of the scalp and so the time since infestation can be approximated because hair grows at a rate of ~1 cm/month.
Parents often worry that infestation is a sign of poor hygiene but all socioeconomic groups are affected. Lice do not spread disease and therefore are not a health hazard.
Transmission is by direct contact with the hair of infested persons or objects such as hats, combs and brushes. The incubation period is 10-14 days but can be lengthened in cold climates and shortened in warm climates. Adult lice can produce eggs after 2 weeks.
According to the American Academy of Pediatrics, first line pediculicide treatment should be with Permethrin 1% over-the-counter topical medication, noting there is resistance to it commonly.
Treatment failure should then be treated with Malathion 0.5% topically. If there is treatment failure with Malathion, then oral Ivermectin is recommended.
All medications should be used as directed. The major safety risk is the medication itself as the infestation does not cause disease.
Permethrin 1% is an over-the-counter topical medication that is applied to the hair for 10 minutes after regular washing and towel drying. One treatment is thought effective since it last for 2 weeks but some people recommend a second treatment at 7-10 days. Permethrin 5% is available by prescription for treatment of scabies but not for lice.
Malathion 0.5% is available by prescription and is an organophosphate pesticide. It is approved for children 6 years and older. It is contraindicated in children < 2 years. It is applied to dry hair and left for 8-12 hours. It is reapplied at 7-10 days only if lice are still present.
Ivermectin is not currently approved by the FDA as a pediculicide. It is given as a single oral dose of 200 micrograms/kilogram with a second dose at 7-10 days. It should not be given to children less than 15 kilograms in weight.
Other medications that are used include various Pyrethrin products, Lindane, Crotamiton, and oral Trimethoprim-sulfamethoxazole.
Efficacy by suffocation of occlusive agents such as petroleum jelly or mayonnaise has not been determined. One recent study showed that hot air was effective.
Manual removal of nits is not necessary to prevent spreading. If nits are still visible, particularly close to the scalp, manual removal may increase success.
Household contacts and other close contacts should be treated prophylactically with a pediculicide. Combs, brushes, etc. should be treated with a pediculicide shampoo or in hot water (> 53.5 degrees Celsius or 128.3 degrees fahrenheit) for more than 5 minutes. Bedding and clothing should be washed in hot water and dried on the hot cycle. Dry cleaning or storing items in sealed plastic bags for 2 weeks also is an effective environmental control. Vacumning is also effective.
Pets do not need to be treated.
Questions for Further Discussion
1. How do you treat Pediculosis corporis or Pediculosis pubis?
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
To view current news articles on this topic check Google News.
American Academy of Pediatrics. Pediculosis Capitis, In Pickering LD, Baker CJ, Long SS, McMillan JA, eds. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th edit. Elk Grove Village, IL: American Academy of Pediatrics; 2006;488-492.
Clayton DH. An effective nonchemical treatment for head lice: a lot of hot air. Pediatrics. 2006 Nov;118(5):1962-70.
Centers for Disease Control. Head Lice Infestation.
Available from the Internet at http://www.cdc.gov/ncidod/dpd/parasites/lice/factsht_head_lice.htm (rev. 8/12/2005, cited 1/22/07).
National Pediculosis Association. Licemeister Nit Comb.
Available from the Internet at http://www.headlice.org/ (rev. 2007, cited 1/22/07).
ACGME Competencies Highlighted by Case
3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
4. Patient management plans are developed and carried out.
5. Patients and their families are counseled and educated.
9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.
10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.
13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.
26. Partnering with health care managers and health care providers to assess, coordinate, and improve health care and how these activities can affect system performance are known.
Donna M. D’Alessandro, MD
Associate Professor of Pediatrics, Children’s Hospital of Iowa
February 12, 2007