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InfestationCommonICD-10 B85.x

Pediculosis (head, body, pubic)

Lice infestation · pediculus humanus capitis / corporis / Pthirus pubis · crabs (pubic)

Pediculosis is infestation with one of three obligate ectoparasitic lice — Pediculus humanus capitis (head), Pediculus humanus corporis (body) and Pthirus pubis (pubic / "crab"). Head-lice are the commonest UK paediatric ectoparasitosis; body-lice predominate in homeless / crowded populations and can vector louse-borne typhus, relapsing fever and Bartonella; pubic-lice are an STI marker. Detection-comb-based diagnosis and wet-combing are first-line management per NICE CKS; topical dimeticone / malathion / permethrin remain pharmacologic mainstays.

CurrentLast reviewed 16 May 2026
Clinical image of Pediculosis (head, body, pubic)
Pediculosis (head, body, pubic). Image sourced from DermNet New Zealand. Used under CC BY-NC-ND 4.0. No endorsement implied.

Biology

  • Pediculus humanus capitis — head louse; transmitted by direct hair-to-hair contact; UK paediatric peak 3-12 years; female > male; no relation to hygiene.
  • Pediculus humanus corporis — body louse; lives on clothing seams; transmitted via clothing / bedding; vector for Rickettsia prowazekii (typhus), Borrelia recurrentis (relapsing fever), Bartonella quintana (trench fever).
  • Pthirus pubis — pubic / crab louse; sexually transmitted; nits at base of pubic hair; can also affect eyelashes (phthiriasis palpebrarum), axillary, beard, chest hair.
  • Lifecycle: egg (nit) → 3 nymph stages → adult (~30 days).

Clinical features

  • Head lice:
    • Itch (delayed 2-6 weeks after first infestation).
    • Nape / post-auricular excoriation; "maculae caeruleae" — bluish bite marks.
    • Live lice on detection comb (gold standard diagnosis).
    • Nits firmly attached to hair shaft; differentiates from dandruff.
  • Body lice:
    • Generalised itch with linear excoriations on trunk, axillae.
    • Lice and nits found in clothing seams (not skin).
    • Risk to vagrants, refugees, war / disaster zones.
    • Vector for typhus, relapsing fever, trench fever.
  • Pubic lice:
    • Pruritus of pubic region.
    • Lice and nits at hair-shaft bases.
    • Macuale caeruleae bite marks on inner thighs / lower abdomen.
    • Eyelash (phthiriasis palpebrarum) — particularly in children (may indicate sexual abuse).
    • STI marker — screen for other STIs.

Differentials

  • Scabies — burrows, web spaces, generalised itch.
  • Seborrhoeic dermatitis, dandruff — flakes not attached to hair shaft.
  • Hair shaft anomalies: trichorrhexis nodosa, pili torti, white piedra.
  • Atopic / contact dermatitis.
  • Insect bites, papular urticaria.
  • Folliculitis.

Investigations

  • Detection combing: nit-comb through wet conditioned hair; visualise live lice on white paper.
  • Dermoscopy of scalp — distinguishes nits / lice from artefacts.
  • Lice / nits identified in clothing seams (body louse).
  • Pubic louse — examination of pubic hair; STI screen.
  • If body louse + fever / petechiae — consider typhus / relapsing fever / Bartonella; bloods, blood film, PCR, serology.
  • Eyelash phthiriasis in child — safeguarding referral.

Management (NICE CKS)

  • Head lice:
    • Wet combing every 3-4 days for 2 weeks with conditioner ("Bug Buster" approach).
    • Topical pediculicide:
      • Dimeticone 4% lotion (Hedrin) — applied 8-12 h or overnight; repeat at day 7-9.
      • Malathion 0.5% liquid — repeat at day 7-9.
      • Permethrin 1% creme rinse — alternative.
    • Treat the whole household if multiple cases.
    • Check school close contacts.
  • Body lice:
    • Hot wash (≥60°C) all clothing / bedding; iron / tumble dry on high.
    • Permethrin 1% to skin once.
    • Treat overcrowding / hygiene access.
    • Public-health notification if outbreak.
  • Pubic lice:
    • Permethrin 1% cream rinse or malathion 0.5% lotion — apply and repeat after 7 days.
    • Treat sexual partners.
    • STI screen.
    • Eyelash: white petroleum jelly TDS × 7-10 days; manual removal of nits.
  • Oral ivermectin: 200 µg/kg × 2 doses 7-10 days apart — for refractory disease, treatment failure, or institutional outbreak.
  • Counsel about post-treatment itch persisting 1-2 weeks despite successful eradication.

References

  1. NICE CKS. Head lice. London: NICE; accessed 18 May 2026.
  2. Salavastru CM et al. European guideline for the management of pediculosis pubis. J Eur Acad Dermatol Venereol. 2017;31:1425-1428.
  3. Mumcuoglu KY et al. International recommendations for an effective control of head louse infestations. Int J Dermatol. 2007;46:153-159.
  4. Brouqui P. Arthropod-borne diseases associated with political and social disorder. Annu Rev Entomol. 2011;56:357-374.

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