A head louse, Pediculosis, is an insect that lives on the human scalp and feeds on blood, which causes itching. Head lice are not known to transmit diseases under natural conditions.
Anyone can get head lice, but they are most common on young school-age children. Personal cleanliness does not prevent a person from getting head lice.
If your child scratches his or her head frequently or if you hear of head lice occurring on frequent visitors to your home or on close friends of your child, inspect your child's hair for:
These look like tiny oval objects glued to the side of the hair shafts. Their length is less than 1/2 the diameter of the head of a pin.
Lice and nits are most likely to be found near the scalp where the hair is thickest, usually behind the ears and around the nape of the neck. Lice avoid the light. They grow from slightly larger than the nit up to 1/8 inch in length.
Hair casts (material from the hair follicles) may be mistaken for nits. Both may be on the hair at the same time. A hair cast looks like a small collar or ball and slides easily along the hair shaft. Hair casts are unrelated to louse infestation.
As a rule, only relatively small numbers of head lice will occur away from their normal host, a person. Away from their host, they will usually die in 3 days or less.
Therefore, the following simple control measures are sufficient to prevent reinfestation after treating the infested persons.
New nits will continue to appear on hair next to the scalp.
Some children, seeming free of lice and nits after each complete treatment will have "repeat infestations." This often occurs while others in similar circumstances (for example, same class in school) remain free of lice.
No new nits will be laid. When first laid, nits are attached to hair near the scalp. As the hair grows, they are moved away from the scalp. By 11 days after a successful treatment, no nits will be closer than 1/4 inch from the scalp.
Controlling outbreaks of head lice can be accomplished by following three simple steps.
Parents can purchase a pediculicide to kill the lice. There are a variety of formulations available as over the counter or prescription products. By carefully reading and following the instructions, parents can successfully eradicate the lice. At times, reapplication may be needed.
Although a tedious and time consuming procedure, nit removal is crucial to eradication. After killing the lice, it is extremely important to remove all nits with a special comb usually provided with lice treatment products. Re-infestation can occur very quickly if all nits are not eliminated. Children will not be permitted to go back to school if they have any nits (most if not all schools have a no-nit policy).
The following hints can be used when combing hair to help ensure complete extermination:
Head lice can survive away from the host for 24 hours and nits have been reported to survive in hot and humid climates for up to 10 days. Yet another reason why it is so important to sanitize the environment.
For more information, contact your school nurse or local health department.