Head Lice - Detection

This leaflet is about how to check for head lice. Other leaflets give more details about head lice, and about treatments.

What are head lice and nits?

  • Head lice are tiny grey/brown insects. They are about the size of a sesame seed (the seeds on burger buns). Head lice cling to hairs, but stay close to the scalp which they feed off. Head lice lay eggs which hatch after 7-10 days. It takes about 10 days for a newly hatched louse to grow to an adult and start to lay eggs.
  • Nits are the empty white eggshells that are left when the lice hatch. Nits look like dandruff, but stick strongly to hair. Unlike dandruff, you cannot easily brush out nits.

How can you tell if you have head lice?

An itchy scalp occurs in some cases. However, many affected people have no symptoms, but can still pass on lice to others. Head lice are difficult to find just by looking in the hair. If you suspect that you have, or your child has, head lice, it is best to do 'detection combing' (described below). Some people advise that you do this to children's hair regularly, about once a week.

Detection combing: wet hair method

This will take 5-15 minutes to check each head, depending on hair length and thickness.

  • 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.) Some pharmacies stock detection combs. One type (Bug Buster® detection comb) is also available on prescription. You can also get them by mail order from: Community Hygiene Concern Tel: 01908 561928 Web: www.nits.net
  • 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 3-5 minutes to check each head, depending on hair length and thickness.

  • Straighten and untangle the dry hair using an ordinary comb.
  • Once the comb moves freely through the hair without dragging, switch to a detection comb such as:
    • The Bug Buster® detection comb (described earlier).
    • The Hedrin® detection comb, which you can buy but is not available on prescription.
  • 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 the thumb. This avoids the risk of the louse being repelled by static electricity as the comb is withdrawn from the hair.
  • Continue combing the hair section by section until the whole head of hair is combed through.

What should I do if I find head lice?

See a pharmacist, practice nurse, or GP for advice on treatment. Briefly, treatment options include:

  • Dimeticone 4% lotion (trade name: Hedrin®).
  • Wet combing using the Bug Buster® comb and method.
  • Isopropyl myristate and cyclomethicone solution (trade name: Full Marks Solution®).
  • Coconut, anise, and ylang ylang spray (trade name: Lyclear SprayAway®).
  • Malathion 0.5% aqueous liquid (has various trade names).

The treatment chosen may depend on your personal preference, and what you have tried before (if appropriate). Each treatment has a good chance of clearing head lice if applied or done correctly and if all affected people in the household are treated at the same time.

All people in the same home, and other close 'head-to-head' contacts of the previous 4-6 weeks should be contacted. Tell them to look for lice and treat if they find any. All people with head lice in the same home should be treated at the same time. This stops lice being passed around again.