Headlice (Pediculosis Capitis)

Comments from Expert Advisory Group

  • Treatment of head lice (Pediculosis capitis) is recommended for persons with active infection i.e. the detection of a living louse

Microscopic appearance of louse

Image source : https://dermnetnz.org/imagedetail/3191?copyright=&label=Louse&caption=Louse




Image of head lice

Louse eggs (nits) in hair

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 Head lice image
  • If one member of the household has a current infection, detection combing of all members should be undertaken. Those found to be infected should be treated. All affected members of the household should be treated simultaneously. Wet combing is recommended in all cases, in addition to when other treatments are used.
  • Topical occlusive agents kill head lice either by coating and blocking its excretory system or else dissolving their exoskeleton (e.g. isopropyl myristate/cyclomethicone, dimethicone). These are considered less likely to induce treatment resistance unlike those agents with a neurotoxic mode of action (e.g. malathion, permethrin). Resistance has been reported to many of the agents with a neurotoxic mode of action.
  • Isopropyl myristate/cyclomethicone should be first treatment choice considering UK cure rates below:
    • Isopropyl myristate - 82%
    • Dimethicone 4% -  70%
    • Malathion 0.5%  - 33 % 
    • Permethrin  -13 %
  • The current recommendation in the case of suspected resistance and treatment failure is to use an agent from a different class for the next course.
  • Most products kill only adult lice and not the ova (nits), therefore treatment is usually repeated 7 days later to kill lice emerging from any eggs that survive the first application.
  • The use of repellent sprays is not recommended.


Headlice Treatment

Wet Combing

Wet combing is recommended in all cases, in addition to when other treatments are used.

Wet Combing has shown cure rates of 57%. 

How to wet comb

  1. Wash the hair using an ordinary shampoo
  2. Apply plenty of conditioner to help with straightening and detangling the hair
  3. Straighten and detangle the wet hair using a wide-toothed comb
  4. When the comb moves freely through the hair without dragging, switch to using a head lice detection comb
  5. Make sure the teeth of the comb slot into the hair at the roots, with the deeply bevelled edge lightly touching the scalp, and draw the comb down to the ends of the hair with every stroke
  6. Check the comb for lice after each stroke, and remove them by wiping or rinsing the comb
  7. Work through the hair section by section
  8. Rinse out the conditioner
  9. Depending on the length of hair, this can take between 10 minutes (for short hair) to 30 minutes (for longer hair)
  10. Repeat the combing procedure in the wet hair to check for any lice that might have been missed the first time

One wet combing session should be done every 3 to 4 days for at least 2 weeks, continued until no lice are seen for 3 consecutive sessions.

Treatment for children < 6 months

Wet combing is recommended on its own for infants <6 months old.

Headlice Treatment Application

Manufacturer's directions for use need to be followed closely to ensure a safe and effective outcome.

When applying treatment:

  • The product should be applied to all the hair, from the roots to the tips
  • Particular attention should be paid to ensuring application to the nape of the neck and behind the ears


Some products for the eradication of head lice infestations are combustible/flammable when on the hair and can ignite and cause serious harm in the presence of an open flame or other source of ignition such as when lighting cigarettes (e.g. Full Marks Solution®, Hedrin®).

Patients and carers should be advised on the safe and correct use of head lice eradication treatments and if appropriate, should be advised that they should not smoke around treated hair and that it should be kept away from open flames or other sources of ignition.

Drug Dose Contact time Repeat application
1st choice options

Isopropyl myristate/cyclomethicone

(Full Marks Solution®)

Adults & Children ≥2yrs


5 minutes


Repeat after 7 to 14 days if necessary



Dimethicone 4%

(Hedrin Treat & Go®)

Adults & Children ≥6months


8 hours


Repeat after 7 days


 2nd choice options

Malathion 0.5%

(Derbac M Liquid®)

Adults & Children ≥6mths


12 hours


Repeat after 7 days



Permethrin 1%

(Lyclear Dermal Rinse®)

Adults & Children ≥6months

(<3 years under medical supervision if sold OTC)

10 minutes


Repeat after 7 to 10 days if necessary


1st choice option in Pregnancy

Dimethicone 4%

(Hedrin Treat & Go®)

8 hours


Repeat after 7 days


Patient Information

Safe Prescribing (visit the safe prescribing page)

Reviewed November 2022

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