HEAD LICE

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

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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.

Within the last couple of weeks my daughter scored her first goal in hockey. She was very excited. Then she had school cancelled for the first time due to bad weather. She was very upset. Even school children have ups and downs in their lives. One of the downs that hits the lives of many school children is head lice. We usually start getting lice questions at the pharmacy in September and October. Head lice doesn’t just happen at the beginning of the school year, though. It can happen at any time.

What are lice? Head lice are parasites that live in humans’ hair. The scientific name for them is Pediculus Humanus capitis, and they 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 called nits every day. Seven to ten days later, the nits hatch and are called nymphs. So the whole life-cycle is about 20-30 days. Adults can only survive 1-2 days without a blood meal. Lice are transmitted two main ways. Lice can be transmitted directly by close contact from one infested scalp to another (i.e. touching heads together). They can also be transmitted indirectly by sharing personal articles that come in contact with the head (ie. brushes, hats, etc). Children from 3 to 10 years old are the most affected age group. However, anyone can get lice, regardless of sex, race, age, hair length or socio-economic status.

What are the symptoms of having lice? The most common symptom is itching, especially around the ears and back of the scalp. There can be small sores, or small scabs 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 1.0 cm from the scalp have grown out with the hair and have either hatched or are dead.

The main product used to treat head lice is permethrin (one of the brand names is Nix). It sticks around 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 the lice, it has low toxicity and it sticks around for about 10 days. Although it is not absolutely necessary to do a repeat application, it is often recommended that one uses the permethrin again in 7 to 10 days. There is a similar product to permethrin on the market and it contains natural pyrethrins (one of the brand names is R&C Shampoo). It is not as good as permethrin at killing the lice. It doesn’t hang around after application. It must be reapplied in 7 to 10 days for it to be effective. Both permethrin and pyrthrins 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.

The newest product on the market for lice is called Resultz. It contains isopropyl myristate. This is different that the Nix like products. 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. Back in the 1980’s permethrin like products killed 100% of lice. I have seen estimates now that in some places in the world it now only kills 28% of the lice. It can be hard to tell if these treatment failures are due to poor application technique, but resistance to permetherin is probably real. 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 it is definitely better than permetherin yet, but it is nice to have another tool against lice.

The Dauphin Clinic Pharmacy has developed an all natural oil lice treatment. It coats the hair and suffocates the lice. We call it Nice ‘N Natural lice treatment. It can be used as an alternative to the commercially available products.

Some non-medication measures should be taken when a family member gets lice. Combs and brushes should be soaked in alcohol or Lysol for one hour; or they can be soaked in water 65oC or hotter for 10 minutes. Bedding, towels, and clothing should be washed in hot water and dried in a dryer for 20 minutes to an hour. It is actually the heat from the dryer that kills the lice. Items that can’t be put in the dryer may be dry-cleaned or stored in a sealed plastic bag for 2 weeks. Lice can’t live away from human contact for very long, so the two weeks allows the eggs to hatch and the new lice to die. Some people have even stored these plastic bags full of teddy-bears etc. in the freezer. Vacuuming of carpets and furniture is also a good idea.

Finally, nit picking (actually combing the live and dead nits out of the hair) is very tedious, but very important.

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