"The first time that I was aware of lice was the day I picked up my 3-year-old son from nursery school," says Deborah Altschuler. "He had been sitting in the corner the entire morning."

The staff discovered that he had head lice and, unable to reach her by telephone, segregated him.

"I was quite upset," she says. "I am fastidious."

She took her son home -- to the middle-class Boston suburb of Newton -- and immediately inspected her 5-year-old son. He had them, too. "I then had myself checked, and I, as well, had lice."

That was October 1982. Altschuler's pediatrician gave her a prescription for a lindane-based shampoo. Lindane is a pesticide. She cleaned an already clean house. "Two weeks later, I checked my kids and found that they had it all over again. And so did Mommy."

This repeated itself four times, the last time Thanksgiving Day. "I was expecting company from out of town. And 45 minutes before they were to arrive, I was bathing the boys and found, once again, that they had lice.

"I sat down. I cried. I carried on. I told my husband that I would not send our children back to the public school because until the school did something, they were just going to get it again and again. And their brains would be pickled by the time they were in third grade from all this garbage that we had to put on their heads."

Until then, Altschuler, 37, who has a degree in education, had told herself that her children really didn't have lice -- just eggs. And that itching -- well, it was from having something in their hair, like sand. "It never occurred to me that the itching was from the sucking of the louse."

Lice are blood-sucking insects. They puncture the skin and pump out blood. Human head lice can only survive on human blood; without it they die.

Altschuler, whose husband is an investment manager, researched the biology and effective, safe treatment of head lice in a medical library. But she was unable to convince an indifferent local health department that hundreds of families were in a situation similar to hers. After all, head lice are not a reportable disease and few families would volunteer the embarrassing information to authorities.

So she and Leslie Kenney, a mother of two girls and the wife of a psychologist, phoned pharmacies in Newton. In the first 12 weeks of school, the druggists had filled 1,650 prescriptions for one lice shampoo alone -- each prescription probably used by two people. Newton has an elementary school population of 5,000.

These statistics finally got the attention of the local government. But Altschuler and Kenney decided the best way to cure the head lice outbreak was to go public with it. They formed Parents Against Lice and newspapers picked up the story.

"That's when all hell broke loose," says Altschuler. "We started getting letters from Hawaii and all the way across. And it has not stopped."

Altschuler estimates that 10 million Americans have head lice each year and they buy at least $100 million worth of lotions and shampoos to combat it.

Head lice in the United States, says University of Massachusetts medical entomologist John Edman, constitutes "a national epidemic."

"You talk to school nurses, read articles, look at how many cans of Rid and what-have-you are sold, ask pharmacists about the preparations bought and it is obviously a very important problem. In many cases, departments of public health from federal on down to the state level are taking a very blase' attitude."

Edman says, however, that Altschuler and Kenney themselves are doing the job. "They are having an impact on preventing the spread, and on policies for dealing with lice."

The two women now have Licebuster T-shirts -- with a big black louse in the center -- that they encourage licebusters across the country to wear when they check school children.

Altschuler and Kenney have changed the name to the National Pediculosis (the medical term for lice infestation) Association to reflect their national network. They say they get 50 letters a day and are active in 47 states. Their efforts are financed by $25,000 in donations from individuals and from such companies as Polaroid, Stop and Shop (which owns the MediMart drugstore chain), Zayre and the Purdue Frederick and Pfizer pharmaceutical companies.

Their association sponsored a clinical evaluation of the five most common shampoos and lotions used to kill lice. David Taplin, professor of dermatology and epidemiology at the University of Miami medical school, did the study.

"I think we could claim a spot in the Guinness World Book of Records for nitpicking," says Taplin, who as head of the field epidemiological survey team has spent the last five years working on head lice and scabies. "We have picked out, and examined, 18,000 nits lice eggs and 5,000 to 8,000 nymphs immature lice and adults."

He tested Prioderm, Rid, A-200, R&C and Kwell. His findings: All of the products killed louse nymphs and adults. With Prioderm, a malathion lotion, only one percent of lice eggs remained alive after treatment. Rid lotion, A-200 lotion and shampoo, R & C shampoo (all containing pyrethrin, an extract of chrysanthemums) and lindane-based Kwell shampoo left about 30 percent of nits alive and able to hatch and reproduce.

In the hierarchy of prestigious research, lice rank low. "Scientists look down their noses," says Taplin, "when you're picking nits and lice out of people's heads."

Whereas head lice in the United States have resulted in primarily a financial drain, they are a serious public health problem in tropical countries. "Children have infected sores all over their heads; they are distressed and fevered and may get kidney problems.

"It is not," says Taplin, "a trivial subject."

In the U.S., head lice infestation is not considered an acute medical problem. Only in severe infestations will children possibly suffer swollen underarm or neck glands, or bacterial infection. The worst problem is usually psychological. Children feel like "outcasts," Taplin says. "Their head itches. They can feel these things crawling on their heads at night.

"It's a disease primarily of kindergarten, first- and second-graders. At this age, they play head to head. Their hats and coats hang next to one another, or land on a clothing heap. They share clothes and combs."

Lice are also an affliction primarily of suburban middle- and upper-class families. "You rarely see head lice on American black children," says Taplin, "partly because the claw of American lice is not adapted to the oval hair of curly-haired blacks.

"Head lice," he adds, "are nothing to be ashamed of. They are as attracted to a clean head as a dirty one. Anyone can have lousy kids."

Meanwhile, lice seem to be gaining in social chic. Bloomingdale's had scheduled a panel discussion on the subject this month at Boston's toney Chestnut Hill mall.