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Clinician’s Corner: Head Lice Treatment

As the yellow bus haul away out kids for another day of learning, your Thompson Pharmacist knows that nothing upsets parents more than when they get the call from the school nurse that their child has head lice.  Truth is, that the first line treatment for head lice is over the counter, and we are glad to help you get the most successful results with these effective products.

For all lice killing shampoos: All topical lice killing products should be rinsed from the hair over a sink rather than in the shower or bath to limit skin exposure and with warm, rather than hot water to minimize absorption int the scalp.

Removal of nits immediately after treatment is not necessary to prevent spread, because only live lice cause an infestation. Individuals may want to remove nits for cosmetic reasons or to decrease diagnostic confusion. Because none of the treatments are 100% effective in killing the eggs, manual removal of nits (especially the ones within ½ inch of the scalp) after treatment with any product is recommended.

Permethrin 1% Crème rinse (NIX®)

Made from a natural chrysanthemum extract, this product is neurotoxic to lice. Permethrin was first approved in 1986 by prescription and in 1990 was moved to over the counter. Is available as a 1% crème rinse, which is first line treatment for head lice.

Mechanism: acts on the parasites nerve cell membrane.  Resulting in paralysis of the pest.

Remains on hair shaft for 14 days, despite normal shampooing.  Can be used as prevention, in “epidemics” where over 25% of the population (family, daycare, or classroom) is affected.  Is 70-80% effective in killing the eggs. We are seeing an increase of resistance to permethrin.

May be used for a child as young as 2 months.

Directions for Permethrin creme rinse:

  1. Wash hair first, with regular shampoo.
  2. Towel dry briskly
  3. Apply enough permethrin crème rinse to saturate hair and scalp (especially problem areas)
  4. Let on hair for NO longer than 10 minutes.
  5. Rinse with water
  6. May reapply in 7 days if necessary. One application is generally curative. However, Permethrin’s adherence to the hair shaft can be affected by conditioners and other ingredients in shampoo. Many experts routinely advise re-treatment on day-9.

Piperonyl Butoxide (4%), Pyrethrum Extract (Equivalent to 0.33% Pyrethrins) (Rid®)

Brand: RID® and other generics are available over the counter

Pyrethrins are extracted from the chrysanthemum flower. Pyrethrins are safe and effective when used as directed. Pyrethrins can only kill live lice, not unhatched eggs (nits).

Piperonyl Butoxide/pyrethrin Lice Killing Shampoo is designed to be used on DAY ONE and then again 7 to 10 days later, but not before. To apply the shampoo, follow the directions on the package, including:

  1. Protect child’s eyes—Use towels to protect child’s eyes from treatment and prevent clothes from getting wet.
  2. Apply Piperonyl Butoxide/pyrethrin Lice Killing Shampoo—Apply thoroughly to DRY HAIR or other affected area. Wetting the hair dilutes the treatment making it less effective.
  3. Let set for 10 minutes—first apply behind the ears and to the back of the neck. Lice can crawl up and down the shaft of the hair very quickly, so it is important to apply the treatment from the roots to the ends of the hair. Allow product to remain on the hair (or other affected area) for 10 minutes, but no longer.
  4. PRECAUTION: A second treatment is recommended 9 to 10 days after the first treatment to kill any newly hatched lice before they can produce new eggs. Pyrethrins generally should not be used by persons who are allergic to chrysanthemums or ragweed. Piperonyl Butoxide/pyrethrin is approved for use on children 2 years of age and older.

RID LICE CONTROL SPRAY (permethrin 0.5%)

Most agree that this treatment is no more effective than a thorough vacuuming with a Shop-vac.  Some sources recommend against using these insecticides at all. Viable nits are unlikely to incubate and hatch at room temperatures which are cooler than a human host; if they did, the nymphs would need to find a source of blood for feeding within hours of hatching.

Be sure to review last week’s column about Head Lice Basics and remember to ask your Thompson Pharmacist who is here to help you.  Go Ahead and ASK, at Thompson Pharmacy it’s all for you!