Introduction:
My head starts to itch when I even write about lice. Lice are a common problem wherever children gather. If you are concerned about lice, you are not alone. Each year, many day-care centers, schools, neighborhoods, extended families, and small family units face this problem.

What is it?
Adult lice (also called Pediculus humanus capitis) are six-legged, wingless insects 2-4 mm long. They have translucent grayish-white bodies, and look a bit like a grain of rice with six legs. Their heads have two tiny eyes (too small to be seen without magnification) and two small antennae (usually visible). Six pairs of hooks that surround the mouth allow them to attach themselves to the skin of the scalp for feeding. The mouth contains two retractable, needle-like tubes that pierce the scalp. Salivary juices are injected into the scalp to prevent blood from clotting, and then the lice feed happily, sucking blood through these same tubes. Their translucent bodies turn reddish brown when engorged with blood. Lice completely depend on the blood extracted from humans for existence, and thus will starve to death after 55 hours without blood.

Adult lice can freely move around a head of hair and travel to another person, clothing, plastic combs or brushes, or upholstered furniture. Adult lice usually live for about a month on a human host. During this time, the females generally lay from three to 10 eggs per day (although some female lice have been known to lay up to 5,000 eggs in their lives when in an environment to their liking).

Lice eggs are called nits. These white, translucent, pinpoint-sized eggs are laid near the base of hair shafts, and move outward as the hair grows (nits found near the tips of long hairs suggest a longstanding infestation). Nits are glued tightly to the side of the hair shafts, and cannot be moved along the shafts or knocked off with fingers. The eggs hatch between ten to fourteen days after they are laid. The empty eggs remain attached to the hair shaft. The newborn larvae must feed on human blood within 24 hours, or they will starve to death. The larvae become sexually mature adult lice within about one week. Adult head lice can survive up to two days away from the scalp, which is how they are transmitted by things like combs, brushes, and hats.

During this whole life cycle, larvae and adult lice deposit their feces in the scalp, which eventually causes itching as the person develops an allergic reaction to the lice stool.

Who gets it?
Lice seem to prefer children to adults, long hair to short hair, and they particularly like the hair of females. Interestingly, lice only rarely afflict African Americans living in North America. The lice in Africa and South America have adapted, however, and cases are common in every group on those continents. Cases of lice are most common in children 3 and 10 years old, but can occur at any age.

Lice have been a nuisance to humans since ancient times. Having head lice is not a sign of poverty or poor hygiene. They have thrived almost wherever humans have been in prolonged close contact with each other. One notable exception to this has been in areas where the pesticide DDT is in widespread use. In the United States, for a period of about 30 years, lice outbreaks were uncommon. Since DDT was banned in 1973, the number of cases of lice has risen steadily. Today, there are about 12 million cases per year in the United States alone.

What are the symptoms?
The hallmark symptom of head lice is itching, but a person may have lice for months before the itching begins.

Is it contagious?
Lice are quite contagious. They spread from person to person when heads touch. Because they can live independent of a person for up to 55 hours, they are also commonly spread via stuffed animals, hats, headphones, combs, brushes, towels, clothing, car seats, sofa cushions, and bedding.

How long does it last?
Each louse lives for about a month, but an infestation of lice will usually continue until treated.

How is it diagnosed?
The best way to diagnose head lice is to inspect the head of anyone who might have been exposed to them using a bright light (full sun or the brightest lights in your home during daylight hours work well). A magnifying glass can make the job easier. Part the hair all the way down to the scalp in very small swaths, looking both for moving insects and nits. The entire head must be inspected to make sure there is no problem. Careful attention should be given to the nape of the neck and around the ears, the most common locations for nits. Even one nit in the hair should be treated. The egg might be empty, or contain a dead larva but then again, it might not!

Frequently, people find "pseudo-nits" and panic unnecessarily. Bits of hair spray, dead skin scales, or loose debris may be seen on hair shafts. These move with pressure from the fingers, and nits do not. Also, live nits glow when exposed to a black light (we use black lights in pediatric offices for inspection) and dead nits and empty nits do not.

How is it treated?
Mechanical nit removal is the cornerstone of lice treatment, although medicines can be a real help.

The Great Lice Adventure

It is important for everyone potentially involved in an outbreak to be treated at the same time. If 99.99 percent of the lice are killed, but .01 percent are not, you already have the makings of another outbreak!

Here is a step-by-step guide for using common, over-the-counter medicines to kill the lice, followed by several great natural remedies. Not all of the following steps are always necessary for an individual child. If the lice are caught early, a single application of an over-the-counter treatment may kill all of the lice and nits. For stubborn cases, especially during school-wide outbreaks, following all of the steps can actually save a lot of hassle and prevent repeated exposure to pesticides!

• Set a community-wide call to action now!
  
  
• Get all the kids excited about The Great Lice Adventure! Have teachers do projects on lice as insects. The more the kids know about what's going on, the better. Use art, storytelling, science, and even math. Start with one louse and calculate how many lice would be on an untreated head at the end of, say, a day, a week, a month ...
  
  
• Print detailed instructions on how to get rid of lice and distribute them to children, parents, teachers, and anyone else who works at the school.

• Begin by treating the head of anyone who has lice with an over-the-counter lice preparation, such as Nix or RID. Many schools now recommend leaving Nix on for 30 minutes. This is longer than recommended by the manufacturers. Leaving the product on longer than recommended may work better, and may be safe, but this has not yet been proven.
  
  
• Carefully comb through the hair using a high quality nit comb.
  
  
• While white vinegar does loosen nits from the hair shaft, it can also deactivate pesticides. As a result, I no longer recommend using white vinegar in conjunction with these products.
  
  
• Another no-no with lice medicines is the use of hair dryers at the same time. Many pesticides work by leaving a residue on the hair that continues to kill lice and nits for several days. The heat from hair dryers may deactivate the chemicals and undo all of your efforts.

• Whatever treatment you choose, removing lice from the environment is critical to breaking the cycle. This can be accomplished by thorough cleaning and laundry.
  
  
• Alternatively, instead of cleaning every inch of the environment, just lock your home up tight and take a trip. Get rid of the lice on your heads, and then get out of town. Lice die after 55 hours without a human host. If you can afford to be gone for at least three days, you will return to a lice-free environment.

• After everyone in the community has completed Day One treatment, it is safe to return to school. Every child, teacher, and staff member should be inspected for lice before re-entry. As each person is inspected, give him or her a sticker -- "The Great Lice Adventure!"

• Shampoo daily and follow with careful nit-combing.

• Repeat an application of Nix (or alternative treatment) somewhere between day 7 and day 14, in order to catch any lice that might have hatched since the first application. Do one final, thorough nit-combing.

• Continue scalp inspections until the lice have left the community -- at least for the time being.

How can it be prevented?
Head lice are best prevented by avoiding close contact with infested people. This means quickly identifying and treating those who are affected. It’s also important to avoid sharing combs, brushes, and towels.