Head Lice

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The idea of head lice makes us recoil.  Of course, they don't carry disease or cause symptoms beyond a little itching.  But I don't want them - and neither does anyone else!  The social detriment of head lice is the most important reason to treat them.

Lice are usually transmitted by crawling from one child to another, through head-to-head contact.  They can't jump or fly.  Live lice can live only on humans, not pets.  They don't live for more than 24 hours off a person.  Live lice survive about 2 weeks; their eggs (“nits”) hatch after 2-3 weeks.

Nits may be laid on hair that falls out, causing other kids in the house to be exposed.  So isolating upholstered furniture, and keeping exposed clothes, pillows and stuffed animals in plastic bags for 2-3 weeks, might reduce the spread.  Running clothes and hats through a hot dryer for 5-10 minutes will also kill them.  Discard hair accessories such as ribbons and headbands.  It's recommended to vacuum floors, carpet and upholstered furniture.

Many products are available for treatment; some work better than others.  I recommend treatment with Nix®, over the counter.  Start by washing the hair with regular plain shampoo. Don’t use conditioners or conditioning shampoo, since the conditioner interferes with the lice-killing action.  Towel the hair until damp-dry.  Then apply the Nix®, saturating the hair completely to the scalp.  Once you've applied it, leave the Nix in for 10 minutes, then rinse it away with warm water (no more shampoo).  Now you can towel-dry the hair.

Using a hot hair-dryer to “cook” the nits and lice is no longer recommended, since there are reports that the live lice can be blown around, infecting others nearby.

While the hair is still slightly damp, use a specialized "nit comb" from the drugstore, to comb out the remaining nits.  (Nit combs have stronger teeth, spaced correctly to catch and pull the nits off the hair.)  Try dipping the comb in white vinegar with each stroke.  Removing all the nits is a lengthy procedure, which may need to be repeated several times.

It's a good idea to re-treat with Nix (and repeat the combing) after 7-10 days (9 days is optimal), to kill lice emerging from surviving nits; sometimes 2-3 subsequent applications are needed.  Family members might also be treated as a prevention.

There seem to be different strains and species of head lice.  They come in different sizes and colors.  Some are more resistant to standard treatments such as Nix.

If the head lice are not killed after a couple of applications of Nix, we might try a prescription treatment.  I try to avoid using Kwell® because of neurotoxicity.  Sulfa antibiotics or Ivermectin are oral medications that can be prescribed.

Things NOT to do if your child has head lice:

  1. Don't panic.  Lice are an annoyance, but they are not a serious problem.
  2. Don't cut the hair.  There is no data to suggest that shorter hair reduces the risk of lice.  In fact, the CDC  suggests that nits laid farther than an inch from the scalp won't hatch anyway.  On the other hand, you don't want to "mark" your child socially as having a contagious disease by giving him an unusual haircut.
  3. Don't exclude your child from school, sports or social activities after treatment.  The American Academy of Pediatrics makes a clear point that "No-Nit" school policies cause social ostracism but don't reduce lice transmission.
  4. If we prescribe Ulesfia® or Malthion (Ovide®), DON'T use a hair dryer; these medications on a child’s head are flammable!

For more information about head lice, see:

The AAP’s latest policy (August, 2010):

The CDC’s complete description of head lice:

Complete instructions for applying Nix and combing the hair:

Copyright © 2011, David M. Epstein MD