Parents like Sarner, who are worried about chemicals, are turning to hair products that use natural oils like rosemary, citronella a tea tree oils to act as a "fragrant force field" around the hair shaft.
Fairy Tales Hair Care, a company started in 1999 by former New Jersey stand-up comic Risa Barash, makes Rosemary Repel shampoo and conditioner, as well as spray and gel products.
Barash said in some lab studies, the product is 94 percent effective.
"The theory is that parents need to wash their child's hair anyway," she said. "So you use it as an extra bonus for lice prevention."
Sarner swears by the shampoo. She had cousins from Israel who arrived with head lice and stayed a week. "It was grotesque," said Sarner. "I could see the bugs crawling on their heads."
"They were living a whole week with us and the girls didn't get it at all," she said.
Sadartha DiNello of New Haven, Conn., said she is terrified her daughter Madisyn will get lice after several outbreaks at her school.
"It's extremely stressful and I am a huge OCD person," she said. "Everything bothers me."
Because Madisyn has asthma, she is nervous about using products with harsh chemical fumes. For the last three years, the girl has shampooed daily with Rosemary Repel.
"She was in a play at school and they had 20 girls changing in one small room," said DiNello. "They all had the same color hats and t-shirts and a lot of the names were not written on things, so everything gets mixed up."
The day of the performance, parents found out a "good portion" of the girls had head lice -- but not Madisyn.
The products are expensive -- $11.95 for a 12-ounce bottle of shampoo -- and only a handful of studies proving their efficacy -- the most prominent one from Israel.
However, some studies from the National Center for Complementary and Alternative Medicine indicate that tea tree oil, which has antiseptic properties, can be helpful in treating lice.
Fairy Tales also now provides a free mobile phone app -- The Facts of Lice -- to give parents real-time alerts of outbreaks sorted by zip code. The information is reported by other parents, school nurses and salon staff around the country because most schools have dropped their "no-nit" policies.
Schools used to require parents to keep their children home until they were lice-free, but the American Academy of Pediatrics now recommends against those policies.
Pediatrician Brown said she supports the academy's position and says no-nit policies are ineffective against a harmless pest that seems to happily "live in harmony" on the human scalp.
"If a child is identified, quite likely he has been sitting there for about a month," said Brown. "To say he can't go back to school is ridiculous."
She also is skeptical of natural products without scientific data to back up their effectiveness. Parents should not be afraid of the chemicals in traditional treatments because if used correctly, they are not absorbed by the skin and pose little health risk, according to Brown.
"I feel sorry for these families when some of their kids are resistant to treatment," she said. "A lot of them want their kids chemical free, but they get way more in their daily exposure to the air and water and soil. This is the reality of living in this world."
Tips for treating head lice:
1. Nit removal from the head by combing is the most important lice control measure. Complete nit removal is time consuming, but it is critical for successful treatment.
2. Use of an effective head louse treatment.
3. Removal of all lice and nits from the environment by washing or vacuuming. There is no need to spray pesticides at home.
4. Daily head checks and nit removal until infestation is gone followed by weekly head checks to detect reinfestation.