Head lice


These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

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To guide staff with the assessment and management of head lice.


Life Cycle of Head Lice:

The life cycle of a head louse



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
  • Pruritus 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.


  • 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.

For difficult to remove eggs from hair away from the scalp, consider the use of a straightening iron to kill eggs. 


  1. AMH Children’s Dosing Companion (2015) Australian Medicines Handbook Pty Ltd
  2. Textbook of Paediatric Emergency Medicine 2nd Edition Cameron Elesevier 2012
  3. Textbook of Pediatric Emergency Medicine, Fleisher, Gary R. Ludwig, Stephen.  6th Edition. 2010

Endorsed by:  Director, Emergency Department   Date:  Mar 2018

 Review date:   Mar 2021

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