Human Louse

Pediculus humanus · Order: Psocodea · Family: Pediculidae

Also called: Body Louse, head louse, louse

Can spread germs or disease. Body lice can transmit diseases in some parts of the world, but none are reported in the United States.

Source: Purdue Extension

Human Louse — Photo: Christine Young, CC BY

Head lice are small, wing-less insects about the size of a sesame seed that live on the scalp and feed on blood, causing itching but no disease. Body lice also feed on human blood and can spread three serious diseases outside the U.S., though none are currently present here.

Source: UC IPM, University of Minnesota Extension, Purdue Extension, Purdue Extension

Is it a pest in the house?

Head lice do not live on pets, do not infest furniture or carpets, and do not transmit disease, though they cause discomfort and embarrassment. Body lice survive only briefly off a human and spread by direct contact or sharing infested clothing.

Source: UC IPM, University of Minnesota Extension, Purdue Extension

Does it bite or sting?

Head lice bite the scalp, taking tiny blood meals and injecting saliva that can cause itching; the bites themselves are painless. Body lice also feed on blood and can act as vectors for disease in other regions.

Source: UC IPM, University of Minnesota Extension, Purdue Extension

How to get rid of it

Treat head lice with an effective insecticide and use a fine metal comb to remove nits; combing is essential regardless of chemicals. Shampoos containing insecticide are available over-the-counter or by prescription. Control body lice by applying insecticide, mechanically removing lice and eggs, and washing clothing and bedding at ≥130 °F then drying on high heat for 20 min.

Source: UC IPM, University of Minnesota Extension, Purdue Extension

Lookalikes

Nits are tiny oval eggs about 0.8 mm long that blend with hair color, and can be mistaken for dandruff or skin debris. Head lice are wingless insects 1/12 to 1/8 inch long, so they can be confused with debris if not examined closely.

Source: UC IPM, University of Minnesota Extension

Where it is found in the US

Recorded in 41 of 51 states and DC. Most records: Kansas, Texas, California, Florida, Iowa, Alaska, Pennsylvania, Illinois.

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Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: introduced in North America; introduced in United States. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

More photos

Human Louse photo 3 — Photo: Matt Muir, CC BY

Human Louse photo 4 — Photo: eebee, CC BY

Human Louse photo 5 — Photo: eebee, CC BY

Human Louse photo 6 — Photo: Ashwin Srinivasan, CC BY

Questions people ask

Do head lice bite?

Yes, they take tiny blood meals from the scalp and their saliva can cause itching.

Source: UC IPM, University of Minnesota Extension

Can lice spread disease?

Head lice do not spread disease, but body lice can transmit three diseases in other parts of the world, though none are present in the U.S.

Source: UC IPM, Purdue Extension

How do I get rid of lice?

Use an approved insecticide shampoo and comb out all nits with a metal lice comb; repeat treatment as directed.

Source: UC IPM, University of Minnesota Extension

Are pets a source of head lice?

No, head lice cannot live on dogs, cats, or other animals.

Source: UC IPM, University of Minnesota Extension

Sources

Purdue Extension: https://extension.entm.purdue.edu/publications/E-245/E-245.html
UC IPM: https://ipm.ucanr.edu/home-and-landscape/head-lice/
University of Minnesota Extension: https://extension.umn.edu/biting-insects/head-lice
Purdue Extension: https://extension.entm.purdue.edu/publichealth/diseases/louse.html

Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia

Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.