A. First, be sure she actually has lice. If you see tiny brown or gray live ones, she does. Dandruff can be mistaken for nits (lice eggs); but if it brushes off easily, it's not a nit.

A few years ago, our whole family got head lice. We did exactly what I tell my patients to do: We used a permethrin creme rinse, being sure to follow the directions exactly. Permethrin and pyrethrin (slightly less effective) are considered relatively safe and are available over the counter. Since these treatments don't work on newly hatched eggs very well, we did a second wash later, as recommended on the label.

We did all the home-control stuff too: cleaned combs and brushes with soap and hot water, washed the bedding and any clothing that may have touched our hair in hot water, and vacuumed rugs and furniture. (Off the scalp, lice only live a day or less, so you don't have to go overboard with those things.) Despite all this, I still found live lice on our heads.

While permethrin and pyrethrin are considered the most effective over-the-counter remedies (home treatments like petroleum jelly or mayonnaise are unlikely to get rid of everything), lice are becoming increasingly resistant to them. Prescription treatments like lindane and malathion can be more effective but may cause seizures or even death, especially when they're used improperly or accidentally ingested.

Instead, what worked for us was a nit comb with long, closely spaced metal teeth. After you detangle the hair with conditioner, go through it section by section, inspecting the comb and dipping it into a cup of water with each pass. Nits that are a half inch or more from the scalp are most likely hatched already and not a problem. It's those close to the scalp, and any live bugs, that you're after. Do this once a day  -- for about ten days  -- until you don't find nits or lice (live or otherwise).