Lice 101 A must-read!

LICE 101

What are head lice?
Head lice is a common infestation of children in the US, affecting 6-12 million people each year. Head lice are not a health hazard, not a sign of uncleanliness and are not responsible for the spread of any disease.
The adult louse is 2-3 mm long (the size of a sesame seed) and usually pale gray. The female lives up to one month and lays approximately 10 eggs (nits) each day. These tiny eggs are firmly attached to the hair shaft close to the scalp with a glue-like substance produced by the louse. The eggs are incubated by body heat and hatch in about 10 days. Hatchlings in turn take 8-10 days to lay new eggs. With a first case of head lice itching may not develop for 4-6 weeks.

How lice spread
Lice cannot hop or fly; they crawl. Transmission in most cases occurs by direct contact with the head of another infested individual. Indirect spread through contact with personal belongings of an infested individual (combs, brushes, hats) is much less likely but can occur.

How to treat positive cases of lice
With the increase in the number of cases of lice there has also been a dramatic rise in the number of “remedies” including over-the-counter shampoos, holistic approaches and prescription medications.
With all of these approaches the treatment generally kills lice but not necessarily the eggs. Consequently, rational therapy is to treat individuals twice, approximately one week apart. The first treatment kills the lice, and after waiting one week for any surviving eggs to hatch, the second treatment kills the hatchlings.

Following is a partial list of the common treatments available:

Over-the-counter shampoos
I.e. NIX, RID or A-200. These are often used as the first line of treatments and were for many years the standard for treating lice. In recent years these shampoos have been found to be ineffective due to the development of resistance.

This involves applying a substance such as Vaseline or mayonnaise to “suffocate” the lice. This is generally unsuccessful as lice can “hold their breath” for hours. They may stop moving when the substance is applied but they regain motion hours later when the substance is washed out.
One possible exception to the above is the “Nuvo” method using Cetaphil gentile liquid cleanser. This is applied to the scalp, dried with a hair dryer to form an adherent film, and left on for eight hours before being washed out. The “shrink-wrapped” film plugs the breathing holes of the lice and then causes death by suffocation. This is a very inexpensive and non-toxic method of treatment.

“Lice Ladies’
For many people, the first call in instances when lice occur is to the lice lady. These businesses have been set up to help parents and are extremely effective. Their approach kills lice by combing out the lice and picking out the nits. The downside is that the cost of this treatment can be prohibitive.

Prescription Products

1. Sklice. This is approved for children as young as six months and is effective with as little as one treatment.
2. Ulesfia. This was the first prescription product developed that kills lice without the use of a chemical and is also approved for children as young as six months.
3. Natroba. The active ingredient is considered organic and can be used in children as young as four.
4. Ovide. This is an anti-lice lotion that kills both lice and their eggs on contact. It has excellent efficacy and so far the lice have not developed much resistance.
5. Kwell. This is an older medication with more toxicity.
6. Elimite. This contains the same ingredient as NIX but may be more effective since it is five times as strong and is left in for six hours. Resistance has made this product less useful over the past several years.

Prescription Pills
An alternative to the arsenal of topical medication used to treat lice is the oral version of the drug Ivermectin. This drug offers the convenience of a pill and takes away the potential problem of topicals not working when they are not diligently applied to every part of the scalp. After the pill is taken the medication travels in the blood stream and when lice bite their human hosts they ingest the medication and then die off. A follow-up second dose of medicine is taken one week later and is used to kill any surviving lice.

Information on medication provided by Dr. Pion, a graduate of Harvard Medical School and an Assistant Professor of Dermatology at Franklin Hospital. He has lectured extensively on head lice and authored a textbook chapter on the subject.