Lice Work, If You Can Get It

(Many parents share such worries, judging from conversations with more than a dozen parents who have battled lice in the past year. That, plus a conviction that lice have become resistant to over-the-counter medications, has led some to turn to unproven treatments.)

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Several weeks later, the vermin reappeared. Prieto's youngest daughter, in pre-kindergarten, got lice, and so did Prieto.

"I'm thinking, how the heck am I going to treat myself?" she says.

Another Lafayette parent told her about Franco, who swept into the Prieto household with her color-coded nit-picking system.

First, Franco uses the barbecue skewers to check the whole head for lice or nits. Then, working outside when weather permits, she divides the hair into small sections and puts small rubber hair bands around each. Next, she dips her comb in rubbing alcohol and begins weeding the insects out, slipping a colored band on each section that's nit- and bug-free. When she finds a nit, she snips off the strand. She chats reassuringly all the while.

She advised Prieto of her recommended routine: Wash and dry all bedding, pillows and towels, vacuum the mattress, house and car seats. Sterilize combs and brushes with alcohol or by boiling in water. Put all bedding in the dryer for 20 minutes every day after that for two weeks -- it's the heat that kills the lice -- and do a cleaning (including vacuuming) every third day. (The CDC recommends somewhat less stringent cleaning.)

Franco advised Prieto to re-treat a week later, using herbal products she sold her: one that claims to dissolve nit glue, a sticky substance that binds nits to hair; and another that's said to kill the lice after it's left on the head one to two hours. Then, she told Prieto, comb thoroughly with a nit comb while the products are in the hair. Next, wash the products out, first with dishwashing liquid and then shampoo. Comb twice a day and re-treat if you see more nits.

"To have somebody who is willing to do this for money and is very good at it, is totally worth it to me," Prieto said. "I found her services to be really invaluable."

Experts are more divided.

Treatment Controversy

Several studies suggest that lice have developed increased resistance to permethrin, the most common active ingredient in OTC treatments.

In 2002, University of Miami researchers found that, after the recommended application time of 10 minutes, Nix killed 3 to 5 percent of lice, while Rid killed 8 percent after 20 minutes. By contrast, prescription Ovide, which contains the insecticide malathion, killed 88 percent at 10 minutes. Lindane shampoo killed only 2 percent of lice at 20 minutes. When the Miami researchers compared their results to similar 1986 and 2000 studies, they found Ovide was the only product that had not become less effective.

Resistance can be compounded by failure to follow treatment instructions.