| Head lice | Head lice | The human head louse is a common pest, frequently found where large numbers of people are in close daily contact. It can be a significant pest in schools, particularly among preschool and elementary-age children. Head lice are typically spread by direct physical contact (head-to-head), or by direct contact with items such as hats, combs or brushes, towels, etc. which have been in close contact with the head and hair of an infested person. The first symptom of an infestation is often an itchy scalp. A rash, sores, or skin infection may develop from excessive scratching.
Head lice may be found as adult insects, nymphs or immature insects, or eggs (nits). They usually occur ONLY on the head and scalp, but may rarely be found on eyelashes or brows. The area above the ears, on the back of the head, and along the neckline are the most commonly affected parts of the scalp. Adult head lice range in color from translucent to dirty white to grayish-black. They are longer than they are broad, typically about 2-3mm long (around 1/16 to 1/8”, about the size of a sesame seed), and are flattened in appearance. Adult lice can crawl quickly, but do not fly or jump. Nymphs are similar in appearance to adults, but may be somewhat smaller and lighter in color. Both adults and nymphs may be easily confused with flakes of dandruff. The small, oval eggs or nits are the easiest stage to locate since they are not mobile. Nits or eggs are cemented tightly to the hair shaft near the base of the hair. The empty egg case will remain attached to the hair after hatching, making it difficult to determine if the infestation has been eliminated. However, nits further than 1/4” from the scalp have usually either hatched or are dead. Use a lice comb or pick nits off with your fingernails. Keep in mind that nits are very difficult to remove but need to be removed to stop the infestation. |
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