Treatment-Resistant Lice Trouble
Every parent dreads a phone call from the school nurse saying, "Please come get your child; we found lice." That starts a whole terrible ball rolling. Not only do you need to leave work or drop whatever you're doing to pick your child up, but you have to purchase medication to get rid of the lice, apply it, wash all bedding and recently worn clothing in hot water, and call everyone with whom your child was in close contact. Now, as if all of that is not enough, there is new research offering evidence that common lice treatments are no longer effective in many parts of the United States.
This not the first time we've discussed this problem, but this new study takes things further and shows that things have gotten notably worse in just the last year. The study, which took place at Southern Illinois University in Carbondale, found that lice in at least 25 U.S. states may be developing widespread resistance to the medications typically used to kill them off.1 The scientists collected samples of lice populations from 30 states throughout the country via the work of local public health administrators. Out of 109 samples tested in total, they discovered that a whopping 104 exhibited high levels of mutations in genes that are associated with pyrethroid resistance.
Pyrethroids are synthetic chemicals used in the over-the-counter medications frequently recommended by pediatricians. They are a form of insecticide also found in some mosquito repellents, pet shampoos, and household bug sprays. Permethrin, the active ingredient in Nix, and pyrethrins (combined with piperonyl butoxide), the active ingredients in Rid, are types of pyrethroids.
The lice samples were all tested for three genetic mutations that are known to alter the bug's nervous system and make it immune to the effects of pyrethroids. The insects with all three mutations together have the highest levels of resistance to the treatments containing these chemicals. This issue has been growing for at least 15 years, when researchers began such testing and found some immunity to pyrethroids among lice populations, but not nearly as much as exists today.
It is uncertain how the resistance began. One theory is that the exposure to the chemicals triggered a mutation in the bugs that helped them adapt and survive. Another possibility is that there were always strains of lice that carried these mutations, but now that many of the bugs without them have died, the mutations are the survivors and they pass their mutations down to new generations.2
Either way, this is potentially distressing because it is estimated that 12 million American kids between the ages of three and 11 get lice each year according to the Centers for Disease Control and Prevention. If quick, simple treatments no longer work, that means either more days spent out of school for children and possibly out of work for parents or parents sending their kids back to school before the lice are gone and spreading the critters further. This is especially concerning since some of the states found to have resistant lice were among the most populous, including California, Texas, and Florida.
However, on a more positive note, maybe this will start moving parents away from putting insecticides on their children's heads. While these medications are recommended by many doctors and sold over-the-counter (which often leads people to assume they can't be too dangerous), they are still strong enough to kill many kinds of insects and have been associated with scalp stinging, irritation, numbness, and occasionally serious allergic reactions.
If lice resistant to pyrethroids are known to be a problem in your area, your doctor may instead suggest a prescription treatment that has no known resistance issues…yet. But instead of going that route and exposing your child to pesticides, you might want to consider a more natural solution. You can purchase a nit-removal comb and meticulously go through your child's hair section by section to remove the nits, or lice eggs. It's time consuming and not much fun for either of you, but it is an effective treatment method if you're meticulous. And you are not putting your child in any potential danger. Another natural option is a spray containing coconut and anise, which was shown in a 2010 study at the Medical Entomology Centre in Cambridge, United Kingdom to be significantly more effective than medications with permethrin for treating lice.3
- 1. Manacher, Ilene. "Lice resistant to common treatments in many states." CBS News. 19 August 2015. Accessed 23 August 2015. http://www.cbsnews.com/news/head-lice-resistant-to-pyrethroid-common-treatment
- 2. "Mutations are random." University of California, Berkeley. Accessed 24 August 2015. http://evolution.berkeley.edu/evolibrary/article/mutations_07
- 3. Burgess, IF; et al. "Clinical trial showing superiority of a coconut and anise spray over permethrin 0.43% lotion for head louse infestation, ISRCTN96469780." European Journal of Pediatrics. January 2010. Accessed 24 August 2015. http://www.ncbi.nlm.nih.gov/pubmed/19343362