Back to school basics about head lice.

Aug 27, 2019

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

Go live in Residence. As my oldest child, Emily, prepares for her final year at DRCSS, I thought I'd try again. For the last couple decades, I've told every high school student who has worked at the pharmacy to try Residence. Very few of them listened to me. I assume Emily will ignore me as well. However as my kid, I'm pretty sure ignoring me is Emily's occupation. But the rest of you, if you are going off to post-secondary education, and there is the option of living in Residence, take it. I had mini-reunion this summer with people I was in Residence with 25 plus years ago. I still talk to and see some of them regularly. I am not in contact with the 350 plus people I took first year Bio with, because I don't know who they are. It is very hard to meet people in large university or college classes. You are forced to meet and interact with people in Residence.

Before shipping my oldest kid off to post-secondary education, we need to get through one more lice season. Back to school can mean back to lice. But no matter what your age, you are never too old or too young for head lice. Let's go over the basics. Head lice are quite common. Having head lice doesn't mean someone has dirty hair. Lice actually seem to prefer clean hair. Children from 3 to 11 years old are the most affected age group. Girls seem to be more affected than boys. However, anyone can get lice, regardless of sex, race, age, hair length or socio-economic status.

What are lice? Head lice are parasites that live in humans' hair. The scientific name for them is Pediculus humanus capitis. Lice are wingless insects with six legs and range in color from white to brown to dark grey. They don't fly and they don't jump. A young louse matures in 10-12 days and the adult is 2-4mm long. They multiply very quickly. Females lay 7 to 10 oval and whitish eggs attached to the base of a hair shaft every day. The eggs are called nits. Seven to ten days later, the nits hatch and are called nymphs. The whole life-cycle is about 20-30 days. Lice are transmitted in two main ways. Lice can be transmitted directly by close contact from one infested scalp to another (e.g. touching heads together). They can also be transmitted indirectly by sharing personal articles that come in contact with the head (e.g. brushes, hats, etc). I was surprised to learn the transmission rate. Apparently, lice will only be transferred 10-30% of the time when someone is exposed. It is believed prolonged head to head contact, ie. over 30 seconds, is required for lice to move from one person to another. Quick head contact or transfer through inanimate objects like combs, brushes or hats is supposed to be uncommon. Adult lice need us for their blood meal. Nits need our head warmth for incubation. Lice and nits die when away from us humans for 55 hours.

What are the symptoms of having lice? Most people don't have any symptoms at all. If a person is going to have symptoms, the most common symptom is itching, especially around the ears and back of the scalp. This itching is from a mild allergic reaction to the saliva of the louse when it feeds on us. There can be small sores on the person's scalp or neck. If these sores get infected, there can be pus. How do you recognize head lice? First you should see nits (the eggs) attached to the base of the hair shafts on the warmer parts of the scalp (the back and sides). The egg or nit is oval and glued to the hair. Nits are laid close to the scalp for warmth, usually around the ears and the nape of the neck. Live nits are brownish in color, and dead ones are whitish. Nits found more than 0.6 cm from the scalp have grown out with the hair and have either hatched or are dead. To know for sure that someone has lice, though, you have to see the live adult louse. Combing with a fine toothed comb is supposed to be 4 times more efficient and twice as fast for finding adult lice as just looking through the scalp.

One non-drug treatment that can be used to treat lice is wet combing. Wet combing every 3-4 days with a fine toothed comb can help get rid of lice. This might not work as well as the lice shampoos, but it is completely safe. Using vinegar with wet combing should be avoided if using wet combing in combination with one of the lice shampoos as the vinegar can inactivate the shampoo.

The main product used to treat head lice is permethrin (one of the brand names is Nix). It stays in the hair for up to ten days after use to kill any more lice that hatch. It is generally the product of first choice because is very good at killing lice, it has low toxicity and it sticks around for about 10 days. Since no lice treatment kills 100% of the nits, it is recommended that one uses the permethrin again in 7 to 10 days. Permethrin can cause allergic reactions in ragweed or chrysanthemum sensitive individuals. There are older products on the market that contain lindane. Lindane is not as good as permethrin at killing lice. It doesn't stick around so you must do a second application in 7-10 days for it to be effective. About 10% of the lindane actually goes into the rest of your body and it can accumulate with repeated exposure. It can cause seizures and other neurologic disorders so lindane is not my favorite product.

There has been talk over the last few years about resistance to treatments like permethrin. Because of the resistance fears, there have been new products developed that don't work like permethrin. One of these is called Resultz. It contains isopropyl myristate. The permethrin in Nix attacks the nervous system of the louse. Isopropyl myristate is more like a soap. It dissolves the waxy outer coating on the louse and the louse dehydrates. The claim is that Resultz kills the louse within ten minutes. The down side to Resultz is it does not kill the nits or eggs in the hair. So you absolutely need to do the second treatment in one week. On the positive side, there is no documented resistance to Resultz. There were small studies where Resultz killed more lice than permetherin. One of these small trials was even done in Winnipeg, MB! I don't know if I am ready to say Resultz is definitely better than permetherin yet, but it is nice to have another tool in the tool box. Another proven treatment is oral ivermectin. Oral ivermectin has been shown to work better then permethrin, but is only available in Canada through the Special Access Program of Health Canada. That means it isn't available to most people.

I'm obviously biased, but my favorite alternative to permethrin is called Nice 'N Natural lice treatment. We compound Nice 'N Nature lice treatment at the Dauphin Clinic Pharmacy with a variety of natural oils. It coats the hair and suffocates the lice. It smells really nice and customers tell us it works really well.

If you are moving from a small rural place to a city next year to go to school, go to Residence. It is really hard to meet people when you are a faceless number in a large school moving from class to class. Then at night you go home to an apartment. Hopefully you will have a couple roommates to talk to. But that's it. And that can be very lonely. I've heard all the complaints about Residence. What if I don't like the food, the people, the expense, or the lack of personal space? None of them are as bad as you think, and there is a huge upside. At Residence your floor becomes your instant social group. You will like some floormates and hate others, but that is fine. You will meet people and do things. And having a social group makes post-secondary education so much more pleasant and less scary. And that is my old man rant of the day.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

As always if you have any questions or concerns about these products, ask your pharmacist.

 


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