woman checking young girl for lice

Mutant Lice: An Unwelcome Visitor to Texas

If the idea of lice is enough to make your skin crawl, a new development — lice with drug-resistant mutations — will make you bang your head against a wall.

As of August, these mutant lice had been found in more than half the states — including Texas.

Head lice are tiny parasites that live in human hair and feed on human blood in the scalp. Because lice easily travel from person to person by sharing personal items or through contact, the spread of lice is often rampant in children in the school or daycare setting.

Finding Lice

If you receive that dreaded letter from school alerting you that lice are present, it’s time to search your child’s head. Grab a bright light and a fine-tooth comb, and then wet your child’s hair. Divide the hair into sections, and then sit your child under the light.

As you comb through the hair, beginning at the scalp, look for the following:

  • Nits (lice eggs) are brown, yellow or tan. Nits will stay close to the scalp and will be firmly attached to the hair.
  • Adult lice, which look like sesame seeds, will move quickly on the hair and the scalp.

If you find lice or nits are present, over-the-counter and prescription shampoos and rinses are available to help remove the parasites. You should exactly follow the directions on the label and then check the hair eight to 12 hours later to make sure lice are removed. Most products recommend that you don’t wash your hair immediately and that you retreat the hair about a week later.

Treating Mutant Lice

It’s not uncommon for insects that are exposed to pesticides — including lice — to develop mutations. When lice are treated with a pesticide shampoo or rinse, a few of the insects might survive, and their offspring might be resistant to the chemicals in the pesticides. The mutant lice that are present in Texas are resistant to permethrin and pyrethrin — the insecticides used in most products that treat lice.

If your child has lice and the permethrin- and pyrethrin-based treatments (such as Rid and Nix) aren’t effective, he or she could have encountered a strain of the mutated lice. In this case, it’s time to call your doctor. Prescription lice treatments that don’t contain permethrin and pyrethrin are available and might help treat your child’s lice.

If you need a pediatrician or dermatologist to help with your child’s lice, visit THPG.org.

Physicians employed by Texas Health Physicians Group practice independently and are not employees of the hospital or Texas Health Resources.

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