Paediatric Acute care Guidelines PMH Emergency Department

Pediculosis humanus Capitis is an obligate human parasite.



  • Spread is mainly through head to head contact – lice can move from one head to another in seconds
  • Spread via fomites is probably low
  • Pruitus occurs in response to mite saliva, but may take several weeks to develop
  • Recurrent infection may result in skin desensitisation and little itch
  • Pruritus results in scratching, with secondary folliculitis and impetigo
  • Eggs (nits) are visible firmly attached to hair shaft, usually within 1cm of scalp and require manual removal



Life Cycle of Head Lice:

Life Cycle


  • Insecticides: none can guarantee to kill all eggs – those not killed or removed manually will hatch 7-10 days after being laid.
  • An important part of management therefore involves manual removal of eggs with a ‘nit comb’ after treatment with an insecticide.
    • Metal ‘nit combs’ are probably superior, however, children with coarse hair may require a plastic comb with slightly wider spaces between the teeth.
    • The addition of hair conditioner prior to combing may ease the process.
  • Risk of transmission via fomites is probably low but washing bed linen in hot wash and sun drying is recommended.
  • Close contacts should be checked for evidence of infestation, and treated at the same time.
  • Resistance to pyrethrins has been reported internationally, therefore it is appropriate to use a different type of insecticide if the infestation is not adequately treated or recurs.



  • Permethrin 1% rinse/shampoo (e.g. Pyrifoam)
    • Used in infants over 6 months
    • Apply to towel dried hair, leave for 10 minutes, and then nit comb out hair
    • Repeat seven days later
  • Dimethicone 4% lotion: ‘Hedrin’: method of physical control
    • Available over the counter
    • Applied to entire length of dry hair, left 8 hours or overnight. Combed out with nit comb.
    • Repeat in 7 days

The 10 Day Conditioner Method:

  • The saturation of dry hair with hair conditioner (any type) will immobilise fast moving lice, allowing manual removal with a nit comb
  • The procedure must be repeated daily for 10 days to ensure removal of new lice as they hatch
  • Examine combings on white paper
    • The presence of dark adult lice (hatchlings are paler) after day 1 means that the process must be restarted as this represents a new infestation and new eggs are likely to have been laid
  • Concentrate on removal of eggs closest to scalp as those >1cm from scalp are likely to already be hatched or dead
  • Check for reinfestation after 4 weeks
  • A magnifying glass and using white coloured conditioner make lice easier to see

Other: e.g. tea tree oil, sassafras oil – there is no evidence that other products are effective.


Internal hospital links

Head Lice Prescription for Patient Contact


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