The other day I got the letter no parent wants to get from their child’s school: “We are writing to inform you there has been a confirmed case of head lice in your child’s classroom…” Great! And the search was on… Thankfully, neither of my kids were affected. But the experience got me thinking about kids (and parents) that are, and my hope is that this article gives you some solid information on what to do if your child does come home with lice and what’s new out there to treat head lice.
Pediculosis capitus, more commonly known as head lice, has been around for thousands of years. Egyptian and Peruvian mummies have been found with nits still present in their hair! Today, in the US, about 12 million cases are diagnosed every year. Children are the most commonly affected due to their close play and sharing of hair care objects. Wintertime tends to be a common time for infection as people spend more time indoors in close contact with one another.
The louse itself is a wingless human parasite. It’s usually the size of a sesame seed, 2-3 millimeters and barely visible to the naked eye. Females will live for 30 days laying 5-10 eggs daily along the length of the hair shaft. The eggs, called nits, adhere to the hair shaft until they hatch and the life cycle begins again. Nits tend to be closer to the scalp or around the nape of the neck due to their need for warmth. Much like mosquitoes, lice feed on human blood.
Symptoms include intense itching on the scalp, neck and behind the ears. If it is the first time infected, symptoms may not develop for 2-6 weeks! A second infection may manifest much earlier, usually 1-2 days. This is due to the body’s immune response (memory) to the foreign saliva and excrement produced by the lice. Diagnosis of lice is usually made simply by listening to the history and visualizing lice/nits. Treatment can be difficult. There are over-the-counter treatments available, which is convenient, but resistance to these is common. Unfortunately, resistance to prescriptions products is common too! Fortunately, new drugs have been developed which tend to be much more effective.
The OTCs include shampoos and rinses containing permethrin and Pyrethrins (a naturally derived product). Both are safe, but people with ragweed or chrysanthemum allergy may react to pyrethrin containing products. While these are both readily available, resistance is common and they are frequently ineffective. Lindane is an older prescription treatment that also has a high rate of resistance and has been found to be potentially toxic to the nervous system of young infants and children, and pregnant/breastfeeding mothers.
There are a few prescription products that have been found to be safe and highly effective. Malathion lotion or gel works very well when used overnight, however, this prescription can only be used in patients 6 years and older. For younger patients, 6 months and up, benzoyl alcohol 5% lotion shows a good response with no resistance noted. The down side is that it can cause significant irritation. The newest prescription product is Natroba. Approved by the FDA in 2011 for patients 4 years and older, it is applied for 10 minutes to dry hair, reportedly has no potential for side effects and a good efficacy with no resistance noted to date. The product also states that it kills the larvae developing in the nits, so the painfully tedious task of nit combing is not crucial to treatment success. In addition to all of these topical prescriptions, there is also an oral medication that is highly effective. Ivermectin is an oral anti-parasitic that is usually taken as a onetime dose. It is safe and the dosage is weight based (30 lbs or greater), so it’s a good option to discuss with your healthcare provider if you or your child has failed other treatments and are feeling frustrated with the whole process.
In addition the above therapies, the additional steps of washing bedding, hats and hair brushes/combs should be undertaken. If old enough to understand, children should be discouraged from sharing hats and hairbrushes, barretts, headbands with their friends to decrease the possibility of transmission. As frustrating as head lice is, it can be effectively treated. If we could prescribe patience for parents going through the process, we would!
