Human Head Louse

External parasites on the human scalp and hair

Obligate hematophages; exclusively feed on human blood several times a day

Wingless insects that crawl but cannot jump or fly; they attach eggs (nits) to hair shafts near the scalp with a specialized glue-like substance

Causes scalp itching and potential local inflammation; not known to transmit systemic diseases; primary risk is psychological distress or secondary skin infection from scratching