One way of determining the nit is to squeeze it between two fingernails; it gives a characteristic snapping pop sound as the egg bursts. Children with nits on their hair have a 35–40% chance of also being infested with living lice and eggs. If lice are detected, the entire family needs to be checked (especially children up to the age of 13 years) with a louse comb, and only those who are infested with living lice should be treated. As long as no living lice are detected, the child should be considered negative for head louse infestation. Accordingly, a child should be treated with a pediculicide only when living lice are detected on their hair (not because he/she has louse eggs/nits on the hair and not because the scalp is itchy). Prevention
Examination of the childs head at regular intervals using a louse comb allows the diagnosis of louse infestation at an early stage. Early diagnosis makes treatment easier and reduces the possibility of infesting others. In times and areas when louse infestations are common, weekly examinations of children, especially those 4–15 years old, carried out by their parents, will aid control. Additional examinations are necessary if the child came in contact with infested individuals, if the child frequently scratches his/her head, or if nits suddenly appear on the childs hair.
Dimethicone, which is a silicone oil, is often preferred due to the low risk of side effects. Pyrethroids such as permethrin have been commonly used; however, they have become less effective due to increasing pesticide resistance. There is little evidence for alternative medicines.Head-lice infestations are common, especially in children. In Europe, they infect between 1 and 20% of different groups of people. In the United States, between 6 and 12 million children are infected a year. They occur more often in girls than boys. It has been suggested that historically, head lice infection were beneficial, as they protected against the more dangerous body louse. Infestations may cause stigmatization of the infected individual. Epidemiology
Reliable data describing the usual incidence of infestation in the general public, in the average school community, or during specific times of the year are lacking. The number of cases of human louse infestations (or pediculosis) has increased worldwide since the mid-1960s, reaching hundreds of millions annually. It is estimated between 1 and 20% of specific groups in Europe are infected.Despite improvements in medical treatment and prevention of human diseases during the 20th century, head louse infestation remains stubbornly prevalent. In 1997, 80% of American elementary schools reported at least one outbreak of lice. Lice infestation during that same period was more prevalent than chickenpox.About 6–12 million children between the ages of 3 and 11 are treated annually for head lice in the United States alone.