Pediculosis capitis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
The head louse (Pediculus humanus capitis) is one of the many varieties of sucking lice specialized to live on different areas of various animals.
As the name implies, head lice are specialized to live among the hair present on the human head and are exquisitely adapted to living mainly on the scalp and neck hairs of their human host. Lice present on other body parts covered by hair are not head lice but are either pubic lice (Pthirus pubis) or body lice (Pediculus humanus humanus).
Pathophysiology
The main mode of transmission is contact with a person who is already infested (i.e., head-to-head contact). Contact is common during play (sports activities, playgrounds, at camp, and slumber parties) at school and at home.
Causes
Pediculus humanus capitis, the head louse, is an insect of the order Anoplura and is an ectoparasite whose only host are humans. The louse feeds on blood several times daily and resides close to the scalp to maintain its body temperature.
Epidemiology and Demographics
In the United States, infestation with head lice (Pediculus humanus capitis) is most common among preschool- and elementary school-age children and their household members and caretakers. Head lice are not known to transmit disease; however, secondary bacterial infection of the skin resulting from scratching can occur with any lice infestation.
Diagnosis
History and Symptoms
Pediculosis capitiss can be asymptomatic, particularly with a first infestation or when an infestation is light. Itching ("pruritus") is the most common symptom of Pediculosis capitis and is caused by an allergic reaction to louse bites. It may take 4-6 weeks for itching to appear the first time a person has head lice.
Physical Examination
An infestation is diagnosed by looking closely through the hair and scalp for nits, nymphs, or adults. Finding a nymph or adult may be difficult; there are usually few of them and they can move quickly from searching fingers. If crawling lice are not seen, finding nits within a 1/4 inch of the scalp confirms that a person is infested and should be treated.
Other Diagnostic Studies
The condition is diagnosed by the presence of lice or eggs in the hair, which is facilitated by using a magnifying glass or running a comb through the child's hair. In questionable cases, a child can be referred to a health professional. However, the condition is overdiagnosed, with extinct infestations being mistaken for active ones. As a result, lice-killing treatments are more often used on noninfested than infested children.[1] The use of a louse comb is the most effective way to detect living lice.[2]
Treatment
Secondary Prevention
Examination of the child’s head at regular intervals using a louse comb allows the diagnosis of louse infestation at an early stage.
References
- ↑ Pollack RJ, Kiszewski AE, Spielman A (2000). "Overdiagnosis and consequent mismanagement of head louse infestations in North America". The Pediatric Infectious Diseases Journal. 19 (8): 689–93. doi:10.1097/00006454-200008000-00003. PMID 10959734.
- ↑ Mumcuoglu KY, Friger M, Ioffe-Uspensky I, Ben-Ishai F, Miller J (2001). "Louse comb versus direct visual examination for the diagnosis of head louse infestations". Pediatric dermatology. 18 (1): 9–12. doi:10.1046/j.1525-1470.2001.018001009.x. PMID 11207962.