It’s August, time to get the kids ready to go back to school. A bunch of children together in class means a lot of close contact, and one of the issues you might have to deal with is head lice. The Centers for Disease Control and Prevention (CDC) believes that 6-12 million children contract head lice in the U.S. every year.
Head lice (pediculus humanus capitis) are parasitic wingless insects that feed on blood which they obtain by biting the scalp. Their presence causes irritation and itching in many, although 50 per cent of kids don’t seem to notice them. Lice are, generally speaking, species-specific: You cannot, for example, get lice from your dog like you could get fleas. You get them only from other humans.
Lately, evidence has emerged that the average head louse has mutated into a “super” louse which is relatively immune to common over-the-counter treatments like pyrethroids. While pyrethroids were successful 100 per cent of the time in 2000, in 2013 the success rate dropped to 25%, due to a new trait called “knockdown resistance” (kdr).
According to a March 2016 study in the Journal of Medical Entomology, kdr lice have been identified in 48 states and Canada, up from 25 states a year or so ago. In 42 states, mutant lice with the resistance trait comprised 100% of the infestations.
This means that currently recommended products by the CDC to eliminate head lice, like Rid, Licide, and Triple X will likely be ineffective in most of the U.S. So how to identify and treat super lice?
HOW TO IDENTIFY HEAD LICE
Super lice look just like regular lice (other than the cape, of course). They’re greyish or yellowish-white as adults and can reach the size of a small sesame seed. Infestation with lice can cause itching and, sometimes, a rash. Unlike body lice, however, this type of lice is not a carrier of any other disease.
With their less developed immune systems, kids often don’t even realize they are infested with lice. Adults, however, are usually kept scratching and irritated unless treated. An interesting fact is that those of African-American descent are somewhat resistant to head lice, possibly due to the shape and width of the hair shaft.
The diagnosis is made by identifying the presence of the louse or its eggs, also known as “nits”. Nits look like small bits of dandruff that are stuck to hairs. They are more easily seen when examined using a “black light”. This causes them to fluoresce as light blue “dots” attached to the hair shafts near the scalp.
A fine-tooth comb run through the hair will also reveal the adult lice and nits. These special combs are used to remove as many lice as possible before treatment and to check for them afterwards. The diligence required to do this eventually led to the coining of the term “nitpicking”.
You will find the nits firmly attached to the hair shaft about ¼ inch from the scalp. They will appear yellowish-white and oval-shaped. The application of olive oil to the comb may make them easier to remove. Many prefer the metal nit combs sold at pet stores for animals to plastic ones sold at pharmacies for humans.
TREATING SUPER LICE
Dr. Kyong Sup Yoon, a researcher involved with the recent studies, believes that the only way to be sure to eliminate the super lice is to use stronger “pediculicides”. These are available by prescription only, so he recommends a visit to the doctor first. Dr. Robin Gehris of the Children’s Hospital of Pittsburgh suggests that using the usual treatments and repeating in a week might work. Some believe that home remedies like olive oil, coconut oil, or mayonnaise could suffocate the pests.
The sharing of personal items can also lead to louse infestations. Clothing, combs, bedding, and towels that are used by multiple individuals are common ways that lice spread from person to person.
Be sure to wash and, more importantly, dry all clothes in hot temperatures (130 degrees Fahrenheit) or, alternatively, place them in the freezer for two or three days.
Another option is to place clothing and personal items (like stuffed animals and toys) in a plastic bag for two a week or two and then shake outside. Adult head lice usually only live a few days off the host.
Over-the-counter products that normally kill lice include:
- Pyrethrins (brand name Rid shampoo, a natural product for adult lice only also found in chrysanthemum flowers)
• Permethrin 1% (brand name Nix lotion, a synthetic pyrethrin that kills lice and their nits)
These would likely require more than one treatment to get “Rid” of resistant lice. For super lice, consider these prescription products available through your physician:
- Lindane Shampoo (prescription brand Kwell; avoided in kids because it’s known to cause neurological side-effects)
• Spinosad (brand name Natroba, a natural insecticide derived from soil bacteria – only for head lice in children 4 year or older)
• Ivermectin 0.5% (brand name Sklice, also from soil bacteria and only for head lice in children 6 months or older)
Here’s the procedure:
- Start with dry hair. If you use hair conditioners, stop for a few days before using the medicine. This will allow the medicine to have the most effect on the hair shaft.
- Apply the medicine to the hair and scalp.
- Rinse off after 10 minutes or so.
- Check for lice and nits using a comb in 8 to 12 hours.
- Repeat the process in 7 days
Combs and brushes should be placed in alcohol or very hot water after treatment. It would be wise for any item that might have been exposed, even if it belongs to unaffected family members.
Want to take chemicals out of the process altogether? Some centers like Lice Clinics of America in Denver, Colorado use heat in special hair dryers about triple the strength of your home unit. This dehydrates the adults and their eggs over a 30 minute period. They also ask that you vacuum the house thoroughly to prevent recurrences.
Although crowded, unsanitary conditions may cause infestations to occur, the cleanest children can be affected if exposed. Treating aggressively and being “nitpicky” will help get rid of super lice.
Joe Alton, MD
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