What has six legs, lays eggs like there’s no tomorrow, and is hated by children and adults alike? That’s right, lice.

Although lice do not cause any disease and sometimes even cause no symptoms, there is nothing else that can get adults and children scratching their heads so fast. As my long-time readers know, the key to getting rid of a bad case of lice is understanding how lice develop and why single treatments are usually not enough to get rid of a bad infestation.

When a young louse hatches from an egg, it cannot start laying eggs right away. It takes about six to 10 days for the louse to mature into an egg-laying adult. Once an egg is deposited into a hair shaft with special lice super glue adhesive, it takes about six days for the egg to hatch. Most lice treatments are not able to kill all the eggs. Even if a product is advertised as an “egg killer,” this claim is probably too good to be true. The only sure way to get rid of a lice infestation is to kill all the hatched lice in multiple waves before any of them are able to mature and lay new eggs. At the minimum, this requires three treatments five days apart. Any interval shorter than five days apart runs the risk that some eggs will have just been laid and will not have hatched after 20 days, and any interval beyond five days runs the risk that an egg will have just hatched and a louse will be able to mature and lay new eggs before the next round of treatment.
 

One problem that we have been seeing with medications for lice treatment is that the lice are becoming resistant to the drugs. Nix- and Rid-resistant lice are increasingly common. There are

prescription  drugs to which lice are less likely to be resistant, but these medicines are also known neurotoxins (poisons to the nervous system). I do not recommend exposing children to these kinds of poisons when other, safer alternatives exist.

In an article published in the journal Pediatrics in late 2005. Dr. Dale Pearlman, a dermatologist in California. showed that applying a suffocating agent to lice in three treatments a week apart was 96 percent effective in killing all the lice on a child. The substance that was used as the suffocating agent was Cetaphil Gentle Skin Cleanser. The use of suffocating agents to kill lice is nothing new. Olive oil, mayonnaise and hair straightener have all been used as suffocating agents. The nice thing about the Cetaphil cleanser is that the treatment involves a drying step that eliminates the greasy mess from the other alternatives. Dr. Pearlman asserts that the drying step also increases the efficacy since the fried lotion cannot accidentally be rubbed out of the hair on towels or bedding before the suffocation takes full effect. Cetaphil is also much less expensive than olive oil, and the clean up for Cetaphil is much easier than oil or mayonnaise.

Detailed instructions can be found on Dr. Pearlman’s Web site Nuvo for Head Lice, but here is a quick summary. Eight to 12 ounces of Cetaphil cleanser must be used. Pour the cleanser into bottle with a pointed tip like a mustard container. Start with a dry scalp and apply the cleanser directly to the scalp in a back-and-forth fashion from one side to the head to the other using about 1/4 of the lotion. Apply another 1/4 of the lotion in a back-and-forth fashion in the perpendicular direction from one side of the head to the other to create a criss-cross pattern. Take your fingers and rub the lotion into the scalp. Apply another layer of lotion in a criss-cross pattern and massage the lotion in again. Comb out any excess lotion and blow dry the hair until all the lotion is dried. This will take longer than drying hair wet with water. Leave the lotion on for eight hours and wash out with normal shampoo. Dr. Pearlman recommends three treatments one week apart, but treatment five to six days apart are more likely to be effective in my opinion.

According to Dr. Pearlman, extensive home cleaning is not necessary with this treatment because nits and adult lice are not able to survive off the surface of the human scalp for any significant length of time. Take special care to clean combs, brushes and bedding as well as changing into new clothes after each lice treatment. Nits may need to be removed with a lice comb in order to return to school

Dr. Chung received his medical training at Harvard Medical School and Children’s Hospital. He practices primary care pediatrics at Pediatric Associates of Brockton. Contact him at The Enterprise. P. O. Box 1450, Brockton, MA

more topics