IT’S a fact of life. If your children go to school or camp, they will each almost certainly end up with at least one case of head lice over the years.

So as the school year winds down and camp season beckons, let’s review.

Between six million and 12 million children a year become infected with lice, according to the Centers for Disease Control and Prevention in Atlanta. The tiny bugs, no bigger than a sesame seed, spread easily among children ages 3 to 11, who are likely to come into close head-to-head contact with one another or share hats, headbands and the like.

Although head lice pose no health threat, they can be an expensive, creepy nuisance. Some estimates put the cost of treating lice at $1 billion a year. Many experts say inexpensive home treatments can be effective. But more than a few parents will pay just about any price, often hundreds of dollars, to get the bugs out of their children’s — and in many cases, their own — hair.

“Some people are just not emotionally willing to deal with lice,” said Jody Gangloff-Kaufmann, an urban entomologist with the New York State Integrated Pest Management program at Cornell University.

I can understand. Not long ago, when an especially rampant outbreak of lice hit my son’s Brooklyn classroom, my husband, who wears his hair in a long, thick pony tail, and I couldn’t stop scratching our heads, didn’t sleep well and spent hours going through each others’ hair looking for creatures. We were, in a word, obsessed. My son and husband both had lice. Mercifully, I escaped unscathed. Nonetheless, I missed a lot of work when my son missed three days of school.

Treating lice has become a full-scale industry in some cities. Hair salons dedicated solely to removing live lice and nits (the lice eggs) without poisons are booming in cities including New York, Los Angeles, Dallas and Boston.

Nitpickers in these establishments charge $50 to $300 a person. Some professionals will make house calls for an even higher fee of up to $500 a head. At that rate, you could be talking about thousands of dollars for an infested family of four. That doesn’t count the cost of time taken off from school and work.

“Except for the ick factor, there’s no real reason to plunk down a hundred dollars or more to treat a case of lice,” said Ms. Gangloff-Kaufmann.

Investing a few dollars in a handful of drugstore products and a willingness to become your own household nitpicker will work just as well, if not better than the fancy salons.

In the view of Richard J. Pollack, an entomologist with the Harvard School of Public Health, “The people in these salons may not understand what they are doing.”

Here are some low-cost steps to take if lice have invaded the heads in your household.

REALITY CHECK The note comes home from school or camp saying lice have been spotted. Don’t jump to the conclusion that your child is among the infested. Instead, comb or finger through your child’s hair thoroughly to look for evidence, parting the hair all the way to the scalp. What you think may be lice or nits could be specks of dirt or dandruff.

Live lice, which can be tan or grayish white, move quickly and can be hard to capture or even see. A magnifying glass can help. Look also for nits — tiny white or yellow eggs that stick like superglue to the hair shaft. If you have trouble removing the suspicious speck, it’s probably a nit. If it brushes right off, it’s far more likely to be dandruff or something else.

For more confirmation, compare what you’ve found to the photos at the Web site of the Centers for Disease Control and Prevention.

“I can’t tell you how many times I’ve been sent specimens from parents, school nurses, you name it, and it turns out not to be a louse,” Mr. Pollack said.

Go for the kill? If your child does have the real thing, it is tempting to run to the drugstore, buy the first lice-killing shampoo you can find (for $12 to $20), use it and forget all about lice.

Unfortunately, it’s not that easy. No pesticide gets rid of the nits. If you do use one of these products you need to reapply about 10 days later in case any eggs have hatched. You may even find you need a third application after another 10 days, because some nits survived the second application.

Even if you use the pesticide, it is still a good idea to follow with diligent combing and nitpicking each day until you are fairly sure the lice and eggs are gone.

More troubling, however, is the fact that in many cases lice have grown resistant to the active ingredients in these over-the-counter products. You may treat and see no results at all. When that happens, pediatricians may provide a prescription for heavy-duty pesticides. Lindane, for example, which is often used in agriculture, is still prescribed in many states for lice.

Although many experts believe exposure in small doses is perfectly safe, many parents worry about using these toxic substances on their children’s heads. Ms. Gangloff-Kaufmann points out that the active ingredient in even over-the-counter lice treatments is the same class of compound that causes complaints when municipalities spray for mosquitoes. “I’m supposed to go ahead and put this on my child’s head?” asks Ms. Gangloff-Kaufmann.

She, for one, advocates nonchemical alternatives.

NATURAL ALTERNATIVES If you’re uncomfortable using pesticides or if resistance is a problem, there is an abundance of natural remedies to choose from.

Parents, professional nitpickers, some pediatricians and other experts have sworn by home remedies like applying mayonnaise, olive oil or conditioners to the hair overnight. The idea is to suffocate the live lice.