Head lice have tormented humans for thousands of years. They are wingless insects about the size of a sesame seed 3-4mm, are whitish to reddish brown, and crawl through hair with claws while feeding on blood from the scalp. They cause itch and irritation, and they lay eggs or “nits” which are 1-2mm whitish pods that attach to hair with a glue-like substance within an inch of the scalp. Nits are found most commonly at the nape of the neck and above the ears. Any nit found several inches away from the scalp is dead but has remained glued to the hair as it grows. After mating, the female louse can lay up to 100 nits in her 30 day lifespan. The nits incubate from the warmth of the scalp and hatch in about 8 days. Most lice infestations have only a dozen or so lice, but they may have hundreds of nits. Lice cannot survive away from the human scalp for more than 36 hours. Head lice are distinct from bed bugs, pubic lice, scabies, and other mites that feed on humans. Head lice do not carry disease and never cause death. |
All human beings are susceptible to head lice if exposed. They infest all social classes and are not deterred by hygiene. (Children from nice, clean, educated, and wealthy families are vulnerable to head lice.) Head lice are rarer in African descendants as they have a more difficult time attaching to the hair. Head lice do not infest pets. They cannot live on furniture or on linens for more than a few hours. Head lice need human blood to feed and require the temperature of the human scalp to hatch the nits. Since head lice cannot fly, they are transmitted from person to person through sharing of combs, brushes, hats, towels, or pillows. Rough and tumble play or napping with heads together are two easy ways children transmit head lice. Since they are so infectious, most schools and day care centers have a “no nit” policy, meaning that children cannot return to school or daycare until every nit is removed from the hair. When the school is alerted to one case of head lice, the school nurse or health aide will inspect all the children in the classroom, sending home any child found to have lice or nits, and inspect them for nits before returning to class. Each year 12-20 million children miss school for this no nit policy. Don’t be ashamed to call the school or daycare center to report head lice. If every infested child is not treated, it will continue for many months. |
- Chemical methods (insecticides)
- Physical methods (heat and combing or pulling nits off the hair).
Chemical methods available today include over-the counter permethrins, synthetic pesticides made from naturally occurring pyrethrins found in chrysanthemums. The most effective of these is “Nix” sold as an over-the-counter lotion applied to clean hair for up to 12 hours and then rinsed. “Nix” has an excellent safety profile and can be used for children down to age two. Treatment should be repeated in another week to kill any nits that hatched after the initial treatment. Further, after treatment, all nits must be combed or picked from the hair, a process that requires many hours for those people with thick hair or heavy infestations. Unfortunately, a significant number of head lice have developed resistance to this chemical.
“Kwell” (Lindane) was a prescription product successfully used for many years, but was withdrawn from the market by the FDA because it was a neurotoxin and a potential carcinogen. It was replaced by “Ovide”
(Malathion) a very effective organophosphate pesticide lotion applied to the hair for 8-12 hours. Organophosphates, while safe for most children, have been known to cause seizures. For more information on treating head lice with
malathion, go to www.cdc.gov and type in head lice for all the latest information. Doctors try to avoid using this prescription-only product as much as possible, choosing less toxic ways to treat children.
Another chemical way to treat head lice is with aromatic oils. One such product is “LiceKiller” (www.licekiller.com) which is a three-step treatment using a combination of oils:
neem, tea tree, karanja, eucalyptus, lavender, peppermint, rosemary, olive, and coconut. It has been proven effective, non-irritating, and as yet has not been found to have any toxic problems. It comes with a nit comb and instructions. It claims to have a money-back guarantee if it doesn’t work. It’s worth a try if you want to avoid more toxic pesticides. However, do not mix the aromatic oils and the OTC “Nix” or “Rid”, as the toxicity is markedly increased!
Mayonnaise or olive oil applied to the hair, then covered with a shower cap overnight work by suffocating the live lice, but do not kill the nits. It is still necessary to comb out every nit after these treatments. Although these methods are nontoxic and will not irritate the scalp like the chemical pesticides can, they are not very effective and may require multiple applications.
Physical methods to treat head lice involve the picking of nits from the hair. It is impossible to tell if a nit is viable or dead by looking at it on the hair. This is why every nit must be picked off to verify that the infestation is gone. Nits should be picked with a very fine-toothed comb, either one that comes with the lice removal kit, or a fine-toothed wire comb from the pet store for grooming dogs. Use plenty of light and a magnifying glass if needed to patiently go through every area of the hair, concentrating over the nape of the neck and above the ears. A vinegar rinse may loosen the glue-like substance that attaches nits to the hair and make it easier to slide the nits from the hair. Also, several studies indicate that using a blow dryer on the high heat setting, moving to a new area when the scalp is too irritated to continue to comb, kills both adult lice and nits. There is a fancy patented nit comb with a blow dryer attached that is quite effective in treating head lice (LouseBuster), but a good wire comb and any high-powered blow dryer will do the trick.
Nit-picking is a tedious job that takes many hours of labor. For those parents who don’t have the time or the inclination to do this, there are businesses that you can pay to do this job. “Hair Fairies” has several salons in the greater Los Angeles area where children can get combed while they play video games and parents get a 14-day guarantee. It is expensive at $75 per hour. Other businesses are mobile and will come to your home to pick nits (The Lice Squad or Nitpickers), but be prepared to pay well for the convenience of their service. |
Since head lice cannot survive longer than 36 hours on household surfaces, do not buy sprays or use bleach to kill head lice. Sheets, towels, and clothing should be washed and put in a hot dryer for at least 20 minutes to kill all lice and nits. Vacuum couches and upholstered furniture, and take stuffed animals and place them in plastic bags for a few days. Don’t go crazy with Lysol! Remember that home surfaces are not the source of the problem, but treat all household members carefully checking for any nits (even if they have no symptoms) to be sure that the infestation is under control. |
