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Head lice

How do I check for head lice?

The only sure way to know you have head lice is to find a live louse in your hair.

Finding what might be a nit (the shell of a louse egg) does not prove someone has head lice. And the only way to check that you've got rid of head lice is to have a look and make sure you or your child doesn't have them any more.

Checking for head lice

You're unlikely to spot a head louse by just looking through the hair. To find one, you'll physically have to get it out of the hair. To do this, you need a comb that can pick out head lice. Unfortunately, these combs are not always easy to find, and you might have to hunt around for one. Some head lice treatments come with fine-toothed combs, so you could ask your pharmacist for one of these. The space between the teeth should be no more than 0.01 inches.
Comb the hair with a regular comb first to get rid of any knots and tangles.
Use the fine-toothed comb to comb the hair thoroughly from the scalp right to the ends of the hair. Work around the head carefully, starting at the front.
Check the comb for head lice after each stroke. If something is on the comb, you need to look closely to make sure that it definitely is a louse. You should be able to see a brownish body, although head lice can look pale if they have not fed for a while. They can also look different if they're against combs of certain colors. Depending on how good your eyesight is, you might also see the legs. If you are not sure it is a louse, brush the object off the comb onto a piece of paper. If it's a louse, it should move.
Once you've been all the way around the head, go through the hair again.
Some people recommend wetting the hair first and using conditioner to make the hair easier to comb.
If you're a parent of a school-age child, try to make checking for head lice a regular part of your routine. You could do it once or twice a month.

Checking you've got rid of head lice

If you've used a medication to treat head lice, you will need to check that it's worked and that all the head lice are gone.
You need to follow the same procedure as above and use the comb to check for head lice.
Check for new head lice three to five days after using a medication and again after 10 to 12 days.
If you find head lice after using medication, don't use the same treatment again. There may be a problem with resistance in your community, which is why the treatment has not worked. Speak to your doctor or pharmacist about what to do. You may need to try a different medication.

This information was last updated on May 11, 2009

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.

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