Head Lice Diagnosis

Authored by Dr Mary Harding, 24 Aug 2016

Patient is a certified member of
The Information Standard

Reviewed by:
Dr Laurence Knott, 24 Aug 2016

Head lice are difficult to find just by looking in the hair. If you suspect that you (or your child) have head lice, it is best to use a detection comb.

Some people advise that you do this to children's hair regularly, about once a week. This may not always be necessary but can be helpful if people you are in contact with have head lice, or if it is a recurring problem.

Detection combing: wet hair method

This will take 5-15 minutes to check each head, depending on hair length and thickness. It is also used as a treatment for head lice.

  • Wash the hair in the normal way with ordinary shampoo.
  • Rinse out the shampoo and put on lots of ordinary conditioner.
  • Comb the hair with a normal comb to get rid of tangles.
  • When the hair is untangled, switch to a detection comb. This is a special fine-toothed comb. (The teeth of normal combs are too far apart and the teeth of 'nit combs' are too close together.) Most pharmacies stock detection combs.
    • Bug Buster® detection combs are available on prescription. You can also get them by UK mail order from Community Hygiene Concern.
    • The Hedrin® detection comb is not available on prescription but can be bought from pharmacies.
  • Slot the teeth of the detection comb into the hair at the roots so it is touching the scalp.
  • Draw the detection comb through to the tips of the hair.
  • Make sure that all parts of the hair are combed by working around the head.
  • Check the comb for lice after each stroke. A magnifying glass may help.
  • If you see any lice, clean the comb by wiping it on a tissue or rinse it before the next stroke.
  • After the whole head has been combed, rinse out the conditioner.
  • Repeat the combing procedure in the wet hair to check for any lice that might have been missed the first time.

Detection combing: dry hair method

This will take at least 3-5 minutes to check each head, depending on hair length and thickness. Although dry combing is an option to detect head lice, it is not useful as a treatment.

  • Untangle the dry hair, using an ordinary brush and comb.
  • Once the comb moves freely through the hair without dragging, switch to a detection comb, as described above.
  • Starting from the base or the side of the scalp, comb the hair from the scalp down to the end of the hair. Comb each section of hair 3-4 times before moving to an adjacent section.
  • Look for lice as the comb is drawn through the hair.
  • If a possible louse is seen, trap it against the face of the comb using your thumb. This avoids the risk of the louse being repelled by static electricity as the comb is pulled out of the hair.
  • Continue combing the hair section by section until the whole head of hair is combed through.

Further reading and references

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