May 13, 2009
By Claire McCarthy, M.D.
Boston Children's Hospital
A few years ago, my head started to itch. Dandruff shampoo didn't seem to help. Finally I asked one of the doctors I work with if she would look at my head. What she discovered wasn't dandruff, it was head lice!
When I checked my husband and the children, I discovered that their heads were covered in lice, too. It took a solid month before we got rid of every last bug. During that month, I learned more than I ever wanted to know about head lice. I'm passing on my knowledge to spare you a similar ordeal.
Having lice doesn't mean you're dirty.
A common and unfortunate misconception is that head lice is due to poor hygeine. This makes lots of people with head lice feel bad. Getting head lice has nothing to do with hygiene; you get lice from other people. And once you've got them, lots of scrubbing just gets you clean head lice.
Lice don't fly or jump.
It's harder to catch lice than you might think. Your head needs to be close to a person's head who has lice. Sometimes lice can be spread by sharing hats or hair brushes. There's no need to panic over a case of head lice. It just contributes to the person (who already may feel dirty) feeling bad.
Lice don't live on furniture, blankets or toys.
Lice need blood to live, which furniture, blankets and toys don't have. Lice really can't hang out more than a day on inanimate objects, so you don't need to go crazy cleaning them.
You should wash all bedding and clothing in the hottest water possible. Stuffed animals that share the bed should either get washed or thrown in the dryer (lice don't like hot temperatures). Anything that can't go in the dryer can be stuck in a bag for a couple of days, and by that time, any lice that might have wandered onto it should be dead.
Vacuuming furniture, like the living room couch, is a good idea. But don't spray insecticides on the furniture. It's not necessary and is unhealthy.
Common insecticides don't always work and strong ones can be dangerous.
Most over-the-counter head-lice treatments contain permethrin and pyrethrin. They are absolutely worth trying. However, some lice are resistant to these chemicals. (Lice have been around since ancient times they've been found on Egyptian mummies and have learned how to survive.) Stronger chemicals, such as lindane and malathion, can be more effective, but they can have very serious side effects (including, rarely, death).
Most non-insecticide remedies out there don't work.
You can buy various "natural" remedies for head lice. None of them has been shown to be effective. Nor has putting mayonnaise, olive oil or petroleum jelly in the hair to smother the lice and it's no fun to get any of that stuff out of the hair afterward (especially the petroleum jelly).
Combing can make the difference.
If permethrin or pyrethrin doesn't work, try combing. It gets the lice out rather than leave dead nits behind as other rememdies tend to do.
You need to get a good lice comb that has long (preferably metal) tines that are very close together (touching). Most pharmacies (and some pet stores) carry them. To comb effectively, you need to get all the hair tangles out first or the comb won't get through.
If you have a small child, do the combing while you have them in the tub. Use hair conditioner so the comb will go through more easily. Comb through one section of hair at a time; check the comb for live lice or nits with each pass, then rinse and/or wipe the comb. For older children, or as an alternative to doing it in the tub, use hair detangling spray as you go through each section to help the comb get through.
Because lice hatch about eight days after the eggs (nits) are laid, it's a good idea to comb every day until you've gone at least eight days without seeing any nits or live lice. Realistically, it takes about two weeks of combing to get rid of an infestation. Think of it as extra quality time with your child.
Having nits doesn't necessarily mean you have lice.
Any nit that is more than a half-inch or so from the scalp is likely hatched and isn't a problem. (Certainly anything more than an inch out is hatched.) If you have used a chemical rinse, nits closer to the scalp may very well be dead. This is why many people object to the "No Nit" policy schools may have where they send kids home if they have any nits. The problem is that if there are any nits anywhere, it's hard to know if there are more or if they are dead. So while no child should ever be shamed or ostracized for any reason, let alone head lice, I encourage families to get a good nit comb, take the time, and get rid of the nits.
Having head lice isn't the end of the world.
We all felt itchy, frustrated and embarrassed when we had head lice in my family. But eventually we got rid of every last bug and nit. And during that month, life went on much as usual except that we spent extra time together every night because of combing sessions, which, actually, was kind of nice.
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Claire McCarthy, M.D. is an assistant professor in pediatrics at Harvard Medical School, an attending physician at Children's Hospital of Boston, and medical director of the Martha Eliot Health Center, a neighborhood health service of Children's Hospital. She is a senior medical editor for Harvard Health Publications.