Start itching. Now.

Super lice are among us, and that's not just a back-to-school ploy to get parents running to the pharmacy aisles.

A recent study published in the Journal of Medical Entomology has found that head lice resistant to the most common over-the-counter remedies appear to be dominant in 42 out of 48 states tested.

Every Pennsylvania sample taken for the study turned up with all-resistant lice. New Jersey was a mix of old-school lice and the newer nasties.

"Our study found more and more insects have this mutation," said John Marshall Clark, a University of Massachusetts-Amherst professor of environmental toxicology and chemistry who led the study.

For quite a while, scientists - not to mention the growing number of lice-removal businesses - have been saying that human head lice appear to be developing resistance to traditional products containing pyrethrins, derived from chrysanthemums, or pyrethroids, the synthetic version.

Permethrin, a type of the synthetic, has been used in over-the-counter Nix since the 1980s, according to the UMass study.

When applied to the scalp, these active ingredients act on the lice's nervous system, paralyzing and eventually killing them. But genetic mutations have made the super lice less likely to succumb.

Out of 138 sampling sites in 48 states for the UMass study, using lice collected by school nurses and professional lice removers, 132 sites had only the resistant lice.

Alaska and West Virginia did not participate.

"Sometimes you just don't find people who want to collect lice for you," Clark said.

Nit-picking alternatives

In recent years, the Food and Drug Administration has approved other lice fighters that, Clark said, are effective against the super lice but require prescriptions. Sklice, Ulesfia, and Natroba all have different active ingredients.

Other products containing dimethicone, a siliconelike substance found in many nonprescription personal care and beauty products, also can be effective, he said. They may also make it easier to get the nits out of the hair.

The American Academy of Pediatrics (AAP) still advises using the usual over-the-counter medicines before resorting to prescription products, noted Nix manufacturer Prestige Brands in an email.

But Prestige recently launched Nix Ultra, a pesticide-free product that contains dimethicone, to combat super lice as well as conventional lice.

Even if your product proves effective, full lice removal can be laborious, as any parent who has dealt with this issue can attest. Not only do many remedies still require you go through a sufferer's head meticulously with a fine-tooth comb, any bed linens and clothing the child has used must be thoroughly laundered.

You can hire a private firm to do all or some of the work for you - at a price, of course.

Head lice don't spread disease and are no reflection of personal hygiene, says the U.S. Centers for Disease Control and Prevention, which estimates that as many as 12 million American children ages 3 to 11 suffer an infestation every year.

Home remedies abound. Some swear by essential oils, but most have had limited study. Mayonnaise, olive oil, petroleum jelly, mouthwash - many experts say give them the miss.

Clark says it's possible that goopy mayo could possibly stop the bugs from moving, but it would take so long, "you'd probably have rancid mayonnaise."

So, what does work?

"The first thing you do is don't panic," said Dawn Nolt, an Oregon physician and AAP spokeswoman. Freaking out just makes an already-upset child more anxious.

Both Nolt and Eileen Everly, a doctor with Children's Hospital of Philadelphia's Karabots Pediatric Care Center, suggest starting with standard over-the-counter treatments containing pyrethroids or a similar compound, following their directions for combing and retreating in 7 to 10 days.

Though some schools send children home if lice are found, the AAP is opposed to that practice. It suggests that schools give parents advice on how to treat their child, but doesn't believe education should be disrupted for something that is unpleasant but not a health hazard.

Whenever lice are found, everyone in the household should be checked and treated if needed.

If first-line treatment doesn't work, it may be time to investigate getting a prescription, though Nolt cautions they can be costly and not necessarily covered by insurance.

Everly advised washing bedding, especially pillowcases, and clothing worn in the last few days in hot water and drying with high heat. Unwashable items should be dry-cleaned. Stuffed animals should be put in tightly closed plastic bags for three weeks, she said. Floors and furniture should be vacuumed.

Head lice survive less than one or two days if they fall off their host and can't feed, according to the CDC.

"People are freaked out about lice because they think they are easier to get than they are," Everly said.

They don't jump like fleas. They are not carried by pets. A lot of transmission is head to head, such as when kids hug each other or share a bed.

It's wise to teach kids not to share combs, brushes, hats, helmets, or clothing, Everly said.

'Crying on the phone'

Common as they are, lice are an emotional issue, especially for parents.

"Half the time, they're crying on the phone," said Ed Steinberg, who runs the Center for Lice Control with its founder, his wife, Ilene.

For about $150 per person, the Wynnewood couple will do lice removal with their own dimethicone products in clients' homes, including nights and holidays.

Another mobile service, Lice Happens, also avoids pesticides, said owner Emily Betterly of Plymouth Meeting. She charges $100 an hour - usually about $200 to check a family of four and treating one member.

She has seen her customer base grow along with resistant lice.

"Part of it is these little buggers are just laughing" at conventional pesticides, Betterly said.

Lice Clinics of America, which has a Conshohocken office, uses a special heat-generating machine, solution, and combing to fight the little menaces. The cost is $189 a head for clinic staff to do the whole job, less if you do some of the work yourself.

UMass's Clark warned it's only a matter of time until yet another generation of lice-fighting products is needed.

"Eventually, the insects will become insensitive to these compounds," Clark said. "And we will have to come up with others."

215-854-2391@ritagiordano