INTRODUCTION: Head lice (Pediculus capitis) are tiny parasitic insects well adapted to living mostly on the scalp and neck hairs of human host. These are mainly gotten by direct head-to-head contact with an infested person's hair, but may on rare occasions be transferred with shared combs, hats and other hair accessories.



They get their nutrients by blood-feeding once or twice a day, and cannot live for more than a day or so at room temperature without free access to human blood. These parasites can survive up to thirty days on a human holding on to hair with hook-like claws found at the end of each of their six legs. They are rarely found on the body, eyelashes, or eyebrows and rarely (if ever) create direct harm, or transmit infectious agents from person-to-person. Head lice are equal opportunity parasites that do not respect socio-economic class distinctions and can infest people at any age, but children are more apt to infestations because of their habit of playing in near contact, sharing hats, headphones, combs and brushes, sleeping bags, stuffed animals, and clothing.

NITS: Head lice eggs are called nits and are laid by the adult female at the base of the hair shaft closest the scalp and look sort of like dandruff, only they can't be gotten rid of by brushing or shaking them off. The eggs hatch about 7 to 11 days after they are laid. Eggs further than 1/4 inch away from the scalp have probably already hatched. Nits are most effectively gotten rid of by combing the hair with a specially designed nit comb. The eggs can be distinguished from dandruff flakes as they are very adherent to the hair shaft, whereas dandruff can be easily moved along the hair shaft.

INFESTATION: Contact with an already infested person is the most frequent way to become infected with head lice. Less commonly, Wearing clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons, recently worn by an infested person. There are 4 critical steps to managing an infestation: the use of an effective head louse treatment; nit removal from the scalp (combing); removal of lice and nits from the household environment by vacuuming, washing, or freezing objects suspected of being infested; and daily head checks and nit removal until infestation is gone, followed by weekly head inspections to detect re-infestation. The MD should be able to tell you if your child is infested with lice and requires treatment.

TREATMENT: Treatment should be considered ONLY when active lice or viable eggs are found. A treatment can create significant side effects in children younger than six months old, the elderly, and any person weighing less than 110 lbs (50 kg), especially when it is used repeatedly over a short period of time. If your child is 2 years old or less, you should not use medicated treatments. Your child's physician may recommend repeating treatment in 7 to 10 days to make sure all the nits have been killed and to avoid any chance of reinfestation. Treatments can be over-the-counter or prescription medications, depending on what has already been tried. It isn't rare for treatments to be unsuccessful because of incorrect use or because the lice may be resistant to the chemical in the shampoo. Following the directions on the product label is also important to ensure that the it works correctly.

Medicated shampoos can usually kill the lice and nits, but it may take a few days for the itching to go away. Some don'ts include: Don't use a hair dryer on your child's hair after using any of the currently available scalp shampoos, because some have flammable ingredients. Don't wash your child's hair for 1 to 2 days after applying a medicated shampoo. Be patient and follow the protocol and preventative tips as directed by your child's physician for keeping the bugs at bay, and you'll be well down the road to keeping your family lice-free.

If you feel like you're following all the recommendations and your child still has lice, it may be because of one or more of the following: there are still some nits remaining behind, your child is still being exposed to someone else with lice, the shampoo you're using isn't working. If your child still has lice for 2 weeks after you began treatment or if your child's scalp looks infected (with pus or sores), contact your child's MD. Vacuuming the carpets, upholstery, and car seats will take care of any lice that fell off before treatment began.

CONCLUSION: Head lice infect hair on the scalp and are more common in close, overcrowded living conditions. Infestation produces intense itching, but does not lead to a serious medical condition. They can be spread when infested hair brushes or combs are shared or when infested bedding, towels or shower caps are shared. Head lice is a growing problem because lice-killing medicines are becoming less effective. Every year, between 6 and 12 million people worldwide become infested. Children ages 3-11 and their families become infested most frequently. Pets are of no significance in transmitting human lice, and should not be treated.

In one study, the estimated yearly cost of infestations in the USA was nearly $1 billion dollars. Girls get head lice more often than boys; women more frequently than men. Anyone can become infested and the presence of head lice is not the result of poor habits. Although it can be challenging to eliminate, you must be steadfast and persistent when dealing with an infestation.