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Mutant head lice invade Massachusetts and other states - what to do

August 26, 2015

Just what we needed to hear as kids prepare to go back to school.

Over-the-counter medications may not be enough any longer to fight those pesky little creatures called head lice. Some 25 states, including Massachusetts, have reported lice populations which have developed a high level of resistance to popular over-the-counter medications.

What are head lice?

According to the American Academy of Pediatrics (AAP), millions of school-aged children get head lice in the United States each year.

Head lice are tiny insects that are about the size of a sesame seed. They feed on tiny amounts of blood from the scalp. They usually survive less than a day if not on a person’s scalp. Lice lay and attach their eggs to hair close to the scalp.

“Head lice is a nuisance, but not dangerous. It is treatable with special shampoos, and once treated children can return to school,” said Dr. Matthew Sadof, a pediatrician at Baystate High Street Health Center – Pediatrics.

Close, head-to-head contact is the primary way head lice are spread. It has nothing to do with poor hygiene or an unclean home environment. The most common symptom of head lice is an itchy scalp, especially behind ears and at the nape of the neck.

To check for lice, part your child’s hair and look at the scalp for small white or yellow-brown specks that are firmly attached to the hair shafts. These are nits - lice eggs in their shell casings. Adult lice are more difficult to spot because they are small and will move quickly away when exposed to light.

If you find lice in your child’s hair, then all family members should be checked.

Why are some treatments not working?

Now the effectiveness of some over-the-counter treatments for lice, such as shampoos and cream rinses, is being called into question.

Dr. Kyong Yoon of Southern Illinois University – a former UMass graduate student – and his team were the first to collect lice samples from a large number of populations across the United States. 104 of the 109 lice populations they tested recently had high levels of gene mutations, which have been linked to resistance to pyrethroids.

A pyrethroid is an organic compound similar to the natural pyrethrins produced by the flower of pyrethrums and used in a variety of commercial household insecticides. They include permethrin, which is the active ingredient contained in most of the common lice treatments sold over the counter.

Which lice treatments are recommended?

In areas with known resistance to an over-the-counter treatment, or when parents' efforts on their own do not work, the AAP recommends that parents involve their pediatrician for treatment with a prescription medication such as spinosad or topical ivermectin.

The AAP does not recommend excessive environmental cleaning, such as home pesticides. However, washing pillow cases and treating natural bristle hair care items that may have been in contact with the hair of anyone found to have head lice are reasonable measures.

“You can reduce your child’s chances of catching these tiny critters by telling him or her not to share hats or scarves or coats. Keep hair relatively short or tied up to prevent hair-to-hair contact,” said Dr. Sadof of Baystate Children’s Hospital.