White Paper – Head Lice

Just the mere thought of head lice can begin to make us itch. Unfortunately, lice do not only infect a certain population. Any person is at risk of becoming infested, whether you have clean or dirty hair. Head lice are parasitic insects found mostly in hair on the head. However, they can also spread to the eyebrows and eyelashes as well. The itching most commonly associated with lice, is actually an allergic reaction to their bites. Other common symptoms include: a tickling feeling, sleeplessness due to increased activity of lice at night, and sores on the head.

There are 3 stages in the lice life cycle. They begin as nits (eggs), hatch into nymphs, then mature into adults. The nits are cemented to the hair shaft close to the scalp and appear white or yellowish in color. They are commonly mistaken as dirt, dandruff, or even hair spray droplets. After about 6-9 days, nymphs hatch. These will mature to adults in about a week’s time. As adults, female lice can lay up to 8 nits per day with a lifespan around 30 days. Removed from the head, lice can only survive about 1-2 days without feeding.

In recent years, treatment resistant lice have become a bigger problem. These are lice that have become exposed to the pediculicide (lice killing treatment), but for one reason or another, are not killed. These lice begin to develop and pass on mutations to new nits. Each time a louse is exposed to medication, but is not killed, it is given the chance to develop resistance. Thus a vicious cycle has begun. These lice are then spread to other people, either through close contact or sharing combs, brushes, helmets, towels, etc. When the newly infected individuals try to treat with the same product it will either be less effective or have no effect at all. The best way to prevent the development and spread of these resistant lice is to treat lice correctly to begin with. Here are some helpful tips for treatment:

  • Most importantly, make sure you use the product as instructed on packaging or as directed by a healthcare provider.
  • Apply liberally all over the hair, especially the roots, scalp and neck.
  • Lather & rinse off after 10 minutes.
  • Use a fine toothed comb to help remove the lice & eggs.
  • Repeat treatment after 7-10 days if indicated.
  • Do not use conditioner or a shampoo-conditioner combination product before treatment. Conditioner can prevent the medication from adhering to the hair shaft.
  • Avoid washing hair for 1-2 days after treatment, to prevent medication from washing out of the hair.
  • Rechecking for lice and nits every 2-3 days for about 3 weeks after treatment will help to continually remove new lice that have hatched and prevent reinfection.
  • Soak hair brushes and combs in very hot water for at least 5-10 minutes.
  • All clothing and bedding should be washed with the hottest setting and dried on the high heat setting.
  • Vacuum furniture and flooring.
  • Anything that cannot be washed or vacuumed sufficiently can be stored in a plastic bag for 2 weeks.
  • The entire family should probably be treated, especially if you are unsure how long the individual has been infected

If you have treated the lice and later find you have lice again, there could be a couple of causes. Either you were reinfected or the lice were never completely removed the first time. You can use an OTC product again to see if this works. You must also find out where the lice are coming from. Some possibilities include:

  • Is there someone in daycare or school that could be passing it on?
  • Have you shared combs, hairbrushes, hats, helmets, clothing, etc. with someone else?
  • Were all clothing, combs, brushes, bedding, flooring, furniture and stuffed animals properly cleaned?
  • Does your child ride the bus or have friends they hang out with after school? You do not want to use the same product more that 2-3 times. If you have tried 2 rounds of treatment with the OTC products and are still experiencing problems talk to a healthcare provider. There are some prescription options available. These are usually more expensive, but also more effective.
  • Product: NIX
    Ingredients: Permethrin
    Prescription or OTC: OTC
    Ages: Approved for those >2 months of age
    Is retreatment needed? Recommended around 7-10 days to kill newly hatched nymphs
  • Product: RID
    Ingredients: Pyrethrins, Piperonyl Butoxide
    Prescription or OTC: OTC
    Ages: Approved for those >2 years of age
    Is retreatment needed? Recommended around 7-10 days to kill newly hatched nymphs
  • Product: Sklice
    Ingredients: Ivermectin
    Prescription or OTC: Prescription
    Ages: Approved for those >6 months of age
    Is retreatment needed? Not needed

Christine Hashman PharmD Candidate 2016