Head lice are small insects (about 1/8 of an inch in size) that live and breed on the human scalp. They live approximately 40-50 days and go through three stages in their life cycle: eggs, nymphs and adults. They are about the size of sesame seeds, brownish in color, and can be detected by carefully inspecting the scalp with a magnifying glass and plenty of light. You should know that head lice are treatable, very rarely cause serious health problems, and don't warrant great concern.

Visual inspection is a very poor way to check for head lice. In a study from Israel diagnosis of louse infestation using a louse comb was found to be four times more efficient than direct visual examination and twice as fast. The direct visual examination technique underestimates active infestation and detects past, non-active infestations.

Head lice CRAWL very fast and require head to head contact for transmission. It is possible that because of the way young children play, head lice are seen more widely amongst primary school children than adolescents or adults.

Anyone can get head lice--it has nothing to do with cleanliness or poor hygiene. Head lice are common among school-age children, particularly those in elementary schools. Head lice are transferred from one person to another through close physical contact or from sharing items like hats, combs, brushes, headphones, etc.

Since head lice need blood to live, their "stinging" of the scalp usually causes itching, which can lead to scabs or blood spots. Scratching behind the ears or the back of the neck is another possible sign. Because lice generally feed at night, infected persons will experience the most discomfort and itching while trying to sleep. However, itching is not always present. You should also look for red marks on the scalp and neck and check the head for lice and nits.

When head lice are removed from the scalp or hair, they usually die within a day or two. Similarly their eggs generally perish within a week when removed from the scalp or hair. Pets do not host or transmit human lice, and you should not be concerned about treating them. There is also no need to treat your home for infestation. Other members of the household, however, shouldn't share personal items like combs, brushes, hats, towels, or bedding with anyone undergoing treatment.

There has been recent coverage in the media that head lice are becoming resistant to all pediculicides. We are consulting with experts in the industry for guidance in studying the issue. In the meantime, the best way to eliminate lice from your household is to follow the instructions for Nix and thoroughly clean head lice infested are as/objects in your home. We recommend that you seek the advice of your physician if after two Nix treatments you feel the product is not working.

It is difficult to track head lice cases because head lice are not considered a disease and therefore public health departments and the Centers For Disease Control do not routinely track the number of head lice cases. However, schools and manufacturers of lice products estimate head lice cases at 12- 25 million infestations a year in the United States alone. Most of those infested are children under the age of twelve.

The most common symptom of a head lice infestation is persistent itching, particularly around the ears, back of the neck and crown, but some people never itch at all. Repeat infestations can cause some individuals to become super-sensitive to bites. Secondary bacterial infections can occur with excessive scratching. See a doctor if this occurs. Diagnosis of head lice is usually made by finding nits (lice eggs).

Getting rid of head lice is a three-step process. You must kill all the live lice, check for and remove all the nits by combing and manual nit picking, and do a reasonable job of cleaning the infested person's belongings and home environment. Please make sure you have head lice before treatment. Many people misdiagnose head lice and treat themselves or their children with chemicals unnecessarily.

People should also be aware that according to entomologists, any insect over time can develop resistance to pesticides. It is not surprising therefore, that many consumers, health professionals and entomologists report that head lice have become resistant to pediculicides. However, failure to follow directions, non-compliance and failure to pick nits manually can also result in a persistent head lice infestation.

If you have used a pediculicide correctly and still have live lice or new nits, you probably have a persistent case of head lice. According to the Palm Beach County Head Lice Task Force and the Head Lice Treatment and Prevention Project at Florida Atlantic University College of Nursing, persistent head lice is defined as three incidents of live lice found over a 6-week period.

There has never been a case of someone getting AIDS from head lice. According to the Harvard School of Public Health, head lice are not known to transmit infectious agents from person to person.