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Pediculosis capitis - Hair and Scalp
See also in: Overview,External and Internal Eye
Other Resources UpToDate PubMed

Pediculosis capitis - Hair and Scalp

See also in: Overview,External and Internal Eye
Contributors: Elyse M. Love MD, Susan Burgin MD
Other Resources UpToDate PubMed


Pediculosis capitis is another term for infestation with head lice (Pediculous humanus capitis).

The head louse is an obligate human parasite that lives exclusively on scalp hair. Transmission occurs mostly via direct head-to-head contact. The head louse can survive up to 4 days on fomites such as brushes, barrettes, and headgear; therefore, indirect transmission is possible. In one study, live lice were found on the pillowcases of 4% of infested study volunteers.

School-aged children, particularly girls, have the highest incidence, but head lice are present worldwide and affect all socioeconomic classes. All races and ethnicities are affected, with the exception of those with coarse, curly hair that lice are not able to properly attach to.

Outbreaks may occur in settings where there is close contact and/or frequent sharing of hair accessories, such as schools, day care centers, and nursing homes.

Worldwide incidence of pediculosis appears to be on the rise, most likely due to growing resistance to therapy.


B85.0 – Pediculosis due to Pediculus humanus capitis

81000006 – Pediculosis capitis

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  • Infestation of the beard, eyebrows, and/or eyelashes is consistent with Pediculosis pubis. Crab lice (pediculosis pubis) may infest the hairs of the eyebrows, eyelashes, scalp, axilla, chest, thighs, and perianal area in addition to the pubic area.
  • The scales of Seborrheic dermatitis may be mistaken for pediculosis capitis; however, these scales are greasy, yellow, irregular in shape, and easily removable, unlike the scales of pediculosis capitis, which adhere to the hair shaft.
  • Trichorrhexis nodosa, Pityriasis amiantacea, Black piedra, and White piedra may be mistaken for nits.
  • Traction alopecia, many inflammatory conditions affecting the scalp (eg, Seborrheic dermatitis, Psoriasis, Folliculitis decalvans, Pemphigus vulgaris), and dried hair products (eg, dry shampoos, hair gels) can produce white or yellow concentrations along the hair shaft. These hair casts are often mistaken for nits. Hair casts fully circumscribe the hair shaft and are freely mobile along the hair shaft.
  • Tinea capitis has similar pruritus and lymphadenopathy but is associated with alopecia. Nits are not found on close examination of the hair.
  • Inflammatory scalp conditions such as Psoriasis, Lichen planopilaris, and Folliculitis all cause pruritic scalp but are morphologically distinctive skin disorders.

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Last Reviewed:02/09/2020
Last Updated:03/19/2020
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Patient Information for Pediculosis capitis - Hair and Scalp
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Pediculosis capitis - Hair and Scalp
See also in: Overview,External and Internal Eye
A medical illustration showing key findings of Pediculosis capitis : Concretions on hair, Lice exposure, Scalp, Pruritus
Clinical image of Pediculosis capitis - imageId=2850527. Click to open in gallery.  caption: 'A close-up of nits along hair shafts on the scalp hair.'
A close-up of nits along hair shafts on the scalp hair.
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