Encountering drug-resistant head lice in the pediatric office
In 2016, a study published in Pediatric Dermatology demonstrated that pyrethroid head lice treatments had decreased in efficacy during the past 30 years, likely due to indiscriminate and widespread use.
“In the United States, filling of prescriptions for the treatment of [lice] infestations had a seasonal peak in July to September from 2012 to 2014, coinciding with the back-to-school period,” Ellen Koch, MD, of the pediatric department at the University of Pittsburgh Medical Center, and colleagues wrote. “There has been an increase of approximately 4% in prescriptions over each prior year, possibly because of more infestations or more infestations failing nonprescription over-the-counter or home remedy approaches.”
Following a review of three biomedical databases on head lice treatments available in the U.S. from 1985 to the present, Koch and colleagues observed a decline to 25% effectiveness for permethrin and synergized pyrethrins (collectively pyrethroids), suspected from overuse in the national population.
Treatment-resistant head lice — dubbed “super lice” by the media — are not a new phenomenon, and it is important to emphasize to parents that although some over-the-counter (OTC) treatments may no longer be as effective as they once were, first-line treatments still work most the time if used correctly.
Infectious Diseases in Children asked Robin P. Gehris, MD, chief of pediatric dermatology at Children’s Hospital of Pittsburgh of UPMC, about how physicians should be addressing possible cases of head lice resistance and what actions can be taken to reduce the likelihood of exacerbating head lice resistance.
Physicians and school nurses should continue to offer OTC agents such as Nix (MedTech) or Rid (Bayer) as first-line therapy. However, with this intervention, they should also be informing patients that some head lice are resistant to these agents. If head lice conditions are not improving, parents should make an appointment with their pediatrician or pediatric dermatologist to evaluate whether a stronger, prescription agent is indicated.
As it currently exists, many school nurses are not even recommending OTC medicated products. Instead, many nurses are starting with less effective therapies, such as mayonnaise or thick moisturizer to “suffocate” the lice, which are not highly effective treatment methods.
We want to avoid having the strongest medicated agents become our new first-line therapies because this approach may foster resistance even to these prescription products. These stronger agents should be used only in the hands of experienced providers who can examine the patient to ensure that it is truly an active case of resistant head lice, rather than a case in which there are no live lice and the parents are, instead, finding empty egg casings — or “nits”— that have remained attached to the hair shaft.
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- Koch E, et al. Pediatr Dermatol. 2016;doi;10.1111/ pde.12982.
Disclosure: Gehris and Koch reports no relevant financial disclosures.