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Head Lice and School Students - October 2004
October 26, 2004
UNIVERSITY PARK, PA - Fall means the start of school, but children may be bringing home more than their books.
Head lice affect more than six million children (more than 10 percent of the elementary school population) every year according to the Bio-integral Resource Center. With increases in head lice incidences at this time of year, IPM strategies should be utilized to prevent or eliminate infestations, says an entomologist at Penn State. IPM, or integrated pest management, promotes the use of many different approaches to reduce pest problems. In addition, education of children, parents and school officials about lice habits, prevention and elimination is key. Education should start even before infestations appear.
While head lice are irritating, they pose no known health risks. According to Steve Jacobs, extension entomologist at Penn State, head lice are tiny insects (the adult is about the size of a sesame seed) that thrive on the warmth, food and moisture a scalp provides. They spend their entire life on the human head. "Head lice glue their eggs (called 'nits') to the base of hairs (one egg per hair), especially near the ears and back of the head, and will hatch in five to ten days, depending on the temperature. There are three nymphal stages (6-12 days), the third followed by the adult stage, which lasts about 30 days. All stages must have blood meals if they are to survive and continue their development. Away from people, lice usually die within one to three days. Rarely, they will live up to ten days," Jacobs explains. A single female may lay more than 100 eggs.
People previously unexposed to lice may experience little irritation from their first bite. However, some individuals become sensitized to the bite and experience a general allergic reaction, which may involve reddening of the skin, itching, and general inflammation. Typically, the longer the louse infestation is present the more irritation results.
Since head lice are easily transmitted in schools and daycare centers where many children have close contact, children in these situations should be inspected regularly for active lice. According to Jacobs, head lice are not caused by poor hygiene or "jump" from one person to another. "They can be transferred between persons who share items such as hats, hairbrushes and combs," he explains. They can also walk from one child's head to another if their heads come into contact.
Family members of any child found with head lice should also be checked for head lice. Unless the problem is addressed at home, an infestation may reoccur. Some school districts have adopted a "no nit" policy and do not allow students back into the classroom with any nits remaining on the hair. However, recent research has shown that most nits, especially those more than 1/4 inch from the scalp, will not develop into lice, so 'no-nit' policies are being reviewed to make sure that children are not being kept out of school unnecessarily. In any case, hatched nits are white while unhatched nits will be colored from a grayish-yellow to dark brown. Because of increased resistance to prescription and nonprescription treatments, head lice may become more difficult to manage than in the past. However, schools should never be sprayed to control head lice.
Traditional treatments for head lice include prescription or over-the-counter shampoos, many of which contain insecticides, more frequent baths and shampooing, and the use of special fine-toothed combs.
If prescription or over-the-counter louse treatments are used, make sure that the instructions from your healthcare provider as well as the directions that come with the products are fully and exactly followed. The federal Centers for Disease Control offer the following guidelines for treating the affected person:
1. Before applying treatment, remove all clothing from the waist up.
2. Apply lice medicine, also called pediculicide (peh-DICK-you-luh-side), according to label instructions. If your child has extra long hair, you may need to use a second bottle. WARNING: Do not use a creme rinse or combination shampoo/conditioner before using lice medicine. Do not re-wash hair for 1-2 days after treatment.
3. Have the infested person put on clean clothing after treatment.
4. If some live lice are still found 8-12 hours after treatment, but are moving more slowly than before, do not retreat. Comb dead and remaining live lice out of the hair. The medicine sometimes takes longer to kill the lice.
5. If no dead lice are found 8-12 hours after treatment and lice seem as active as before, the medicine may not be working. See your health care provider for a different medication and follow their treatment instructions.
6. A nit comb should be used to remove nits and lice from the hair shaft. Many flea combs made for cats and dogs are also effective. Finer-toothed nit combs, available through Wal-Med and the National Pediculosis Association may also be helpful.
7. After treatment, check hair every 2-3 days and use a nit comb to remove any nits or lice you see.
8. Retreat in 7-10 days because insecticides generally do not kill the eggs.
9. Check all treated persons for 2-3 weeks after you think that all lice and nits are gone.
Some populations of lice are becoming resistant to the insecticides found in some of the shampoos. When resistance occurs, treatments with the insecticidal shampoos are not effective.
Combing by itself, if done diligently, can be very effective. Special 'nit combs' are used to remove live lice and nits from the hair shafts. Combing should be done very close to scalp because that is where the newly laid eggs are laid. Combing each day until no live lice are observed may eliminate an infestation. Thorough combing must be carried out for at least two weeks. Clean the comb frequently during combing to remove lice and eggs. Of course, shorter hair makes this whole process easier. If hair is cut, thoroughly vacuum up the cut hair and immediately dispose of the vacuum cleaner bag.
In addition to treating the infested person, the household environment also needs attention, but never spray a pesticide in the house for lice. In the household:
1. To kill lice and nits, machine-wash all washable clothing and bed linens that the infested person touched during the two days before treatment. Use the hot water cycle (130 degrees Fahrenheit) to wash clothes. Dry laundry using the hot cycle for at least 20 minutes.
2. Dry clean clothing that is not washable, (coats, hats, scarves, etc.) OR
3. Store all clothing, stuffed animals, comforters, etc., that cannot be washed or dry cleaned into a plastic bag and seal for 2 weeks.
4. Soak combs and brushes for 1 hour in rubbing alcohol, Lysol, or wash with soap and hot (130 degree Fahrenheit) water.
5. Vacuum the floor and furniture. Do not use fumigant sprays; they can be toxic if inhaled.
To prevent the spread of head lice, Jacobs says parents should instruct their children to avoid wearing anyone else's hat, avoid sharing combs or hairbrushes, and, if in close contact with a large group of children, tie back long hair. Reinfestation by lice can take place at any time, so children should continue to be inspected even after a treatment regime.
Schools should provide proper garment storage. Children's hats, coats and other garments should be separately stored, in individual lockers or cubicles if possible. In a louse outbreak even storing individual child's garments in separate plastic bags will help.
For more information on head lice and other nuisance pests see the Pennsylvania IPM Program's Pest Problem Solver on head lice at http://paipm.cas.psu.edu/441.htm.
The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and nonagricultural situations. Integrated pest management, or IPM, aims to manage pests -- such as insects, diseases, weeds and animals -- by combining physical, biological and chemical tactics that are and environmentally compatible. For more information on the program, call (814) 865-2839, or visit the program's Web site at http://paipm.cas.psu.edu/. To view our archived news releases, see Web site http://paipm.cas.psu.edu/10.html.