PASADENA, Calif. — For M. Evan Parker and Frank Campos, business is pretty lousey these days — and that's just fine.

The pair started their in-home lice-removal service, Lousey Nitpickers, in July, budgeting $8,000 to launch a Web site and buy a supply of hair-care products, towels and nit combs.

Six months later, the company's revenue is still very small. And like most fledgling entrepreneurs, Parker and Campos face several tough challenges in creating a sustainable and profitable venture, business consultants said.

But with sales steadily expanding, Parker and Campos are optimistic that their business will continue to grow, given the demand from frantic parents who discover their children have head lice.

The company fields an average of 10 calls a day, some days as many as 25; most are direct referrals from past customers.

"People don't tend to book us in advance," said Parker. "By the time they call, their child's been sent home from school and they want treatment that day."

Accommodating as many as 90 itchy customers a month can keep Campos, the company's chief nitpicker, another full-timer and three part-time employees busy from 7 a.m. until 10 p.m., shuttling to homes across the Los Angeles area.

The two men, who have known each other for a couple of years, found their nit niche after years in the hair-care business. A licensed cosmetologist, Parker, 43, had earlier developed and marketed a line of hair products. Campos, 21, had worked at a children's hair salon in Los Angeles. Neither is a stranger to lice.

The bugs are as old as civilization itself, with references in the Old Testament to "the plague of lice." The insects pick no favorites or seasons and plague people of any age, said Vermont pediatrician Barbara Frankowski, who chairs the American Academy of Pediatrics' council on school health. But infestations spread most easily among preschool- and school-age children, she said.

"Little kids hug each other and snuggle up close on the bean bag chair in the classroom to read together," she said.

The result: 6 million to 12 million Americans are infested with head lice each year, according to the National Science Foundation.

Given a permanent bull market for nitpickers, Parker thought an in-home service would be a more cost-effective business than a salon with fixed overhead. His idea is not new. The LiceSquad is a similar service headquartered in Ontario, Canada, and Parker says wealthy families have long been able to afford hairdressers who would make discreet house calls.

He figured there would also be a market among middle-income families.

The strong demand for nitpickers is also because of the development of so-called super lice, which have grown resistant to commercial and prescription products in recent years.

Lice have developed a tolerance to insecticide-based shampoos because the products haven't always been left in the hair long enough or been repeatedly used as directed, Frankowski said. "The same thing happened with antibiotics," she said.

That's why Campos and his colleagues rely more on pains-taking nitpicking to end the infestation.

Parker initially expected that the company's printed materials and Web site, louseynitpick ers.com, would be its best marketing tool. But by the third month, he said, referrals from customers and schools began multiplying almost as fast as lice themselves and now generates at least 40 percent of new customers. In hindsight, he said, he wishes he hadn't ordered so many pamphlets.

Jim Lee found Lousey Nitpickers — and his family's deliverance from weeks of lice — by going online.

Lee's 4-year-old Karissa started scratching first, in mid-October, then 2-year-old Micah and finally Monica Lee, 40.

The family had tried a prescription shampoo and two commercial products to kill the pinhead-sized critters. For good measure, Monica cut several inches from Karissa's long hair. She also slathered her own long hair with mayonnaise and covered her scalp with a plastic bag, one of several home remedies some believe can suffocate the bugs.

When all that failed, Jim searched on the Internet for lice-removal service.

"I figured there's got to be someone who does this," said Jim, 42, head chaplain at Oaks Christian School in Westlake Village. "And if not, I said I'll start the business myself."

Typically, Campos first makes an inspection to assess the degree of infestation, then he shampoos and conditions the hair before settling down to work with his nit comb.

The company will make a return visit within 14 days in case a nit missed in the initial treatment has hatched. The nit gestation period is a week to 10 days, and getting every last one is key, pediatrician Frankowski said.

The service costs $150 to $200, depending on the number of infested people in the household and the length and thickness of their hair.