Head Lice can be diagnosed by seeing the bug itself, or more commonly be seeing it’s eggs… the "nit" which is a small hard oval tightly attached to the hair shaft about 1-2cm away from the scalp.  In recent years a number of new and better treatments for Head Lice have become available, both prescription & non-prescription.  Most cases of Head Lice will respond to the non-prescription treatments, which are safer and should always be used first.  The best of these are Nix and Rid, with Nix having a slight edge.  Both products are easy to find and come with good instructions in the package.  Nix can be left in the hair for 30 minutes, rather than the 10 recommended by the manufacturer, and this longer application may reduce the chance of treatment failure a bit.

We disapprove of Lindane (Kwell), and never prescribe it.  It is a very old prescription Lice medication which is no stronger or more effective than newer over-the-counter treatments.  It is, however, far more dangerous/risky than Nix or Rid (which is why it remains a prescription drug).  Lindane can cause brain damage.  While that certainly doesn't happen to everyone who uses it, the younger the child and the more of it which is used (in area of skin, duration of contact, and number of uses over time) the higher the risk.   In some cases, the brain damage may be subtle (learning, memory weaknesses).   In some cases, it may be profound (severe mental retardation). 

The two most common reasons for treatment failure or relapse with Head Lice are:

1. Failure to carefully and complete remove ALL the nits from the hair using a "nit comb".  These nits are the eggs the louse attaches to hair shafts very tightly about ½ inch away from the scalp.  Removing them involves a lot of pulling and children (rightly) complain bitterly while you're doing it, but it must be done.  Some of the nits will always survive any treatment you apply, and if not removed will hatch and the problem is right back.

2. Re-infestation.  Very often, a child will keep "catching it back" from a friend or relative or classmate who hasn't been treated and may not even know they have the problem.  This is the reason school nurses have such a field day checking entire classrooms.

A third, emerging new reason for treatment failures are lice which have become resistant to standard drugs like Nix & Rid.  One solution for this is a new prescription drug, Ovide (Malathion).  While it works no better on non-resistant Lice than other treatments do, Lice which are resistant to other drugs do tend to be sensitive to Ovide.  Malathion has been around for many years as an insecticide used against mosquitoes or fruit flies, and there has been controversy about it's safety.  While it is certainly less dangerous than Lindane, the jury is still out on whether it is completely harmless or not.  For that reason, we reserve this treatment for children who have failed treatment with Nix or Rid despite good nit removal efforts. 

Drugs are not the only way to get rid of Head Lice!  Cutting hair may work but only if you literally get a crew cut - the hair must be shaved to a length less than ½ inch in all areas so the lice have nowhere to attach eggs. This is a bit more cosmetically acceptable for boys than girls most often.   Suffocation of the lice by covering the head thickly in mayonnaise under a bathing cap and leaving it on overnight has also been used - for some reason this only works with "genuine" mayonnaise and you STILL have to be sure to comb out all the nits afterwards.

You should be sure that what you are dealing with is REALLY lice.  If you have seen the actual adult louse that's hard to mistake.  But if you are only seeing nits, people often mistake scaling scalps or dandruff or even dirty hair for nits.  Nits are HARD to remove.  They are glued tightly to the hair shaft.  Things that look like nits but pull off or move easily probably aren't.  Also, just because you see a few nits several days or weeks after treatment doesn't mean the treatment failed.  It may just mean you didn't comb out all the nits.  Re-infestation or treatment failure is indicated only by the presence of live lice OR clearly increasing numbers of nits.

Lice are passed from person-to-person.  They can literally "jump" from one head to another.  They need body heat, however, and cannot survive long off the scalp.  For that reason there is no need to wash or disinfect cloths, bed linens, toys, furniture or other inanimate objects as part of a treatment course for Lice.  They can be present in symptom-free individuals, however, so carefully checking all family members, both adults and children, and treating them simultaneously if in doubt, is a good idea.

Finally, remember the good news:  Lice may be gross and yucky, but the worst thing they do is cause itching. They cause no harm to the body, they are not a sign of uncleanliness, and they do not spread disease.   So keep it in perspective and don't get crazy over this.

© Copyright 1997, 2004 by David A. Ansel, M.D.