Pandemic Tamped Down Lice and Scabies Cases in North Carolina, Study Finds

Heidi Splete

August 10, 2022

The incidence of lice and scabies decreased significantly among children and adults in North Carolina during the confinement period of the COVID-19 pandemic, between March 2020 and February 2021, according to a report in Pediatric Dermatology.

When COVID-19 was declared a public health emergency by the World Health Organization in March 2020, many countries including the United States enacted lockdown and isolation measures to help contain the spread of the disease. Since scabies and lice are both spread by direct contact, "we hypothesized that the nationwide lockdown would influence the transmission of these two conditions among individuals," wrote Marianne Bonanno, MD, of the University of North Carolina, Chapel Hill, and colleagues.

"The pandemic created a unique opportunity for real-life observations following physical distancing measures being put in place," coauthor Christopher Sayed, MD, associate professor of dermatology at UNC, said in an interview. "It makes intuitive sense that since lice and scabies spread by cost physical contact that rates would decrease with school closures and other physical distancing measures. Reports from other countries in which extended families more often live together and were forced to spend more time in close quarters saw increased rates so it was interesting to see this contrast," he noted.

In the study, the researchers reviewed data from 1,858 cases of adult scabies, 893 cases of pediatric scabies, and 804 cases of pediatric lice reported in North Carolina between March 2017 and February 2021. They compared monthly cases of scabies and lice, and prescriptions during the period before the pandemic (March 2017 to February 2020), and during the pandemic (March 2020 to February 2021).

Pediatric lice cases decreased by 60.6% over the study period (P < .001). Significant decreases also occurred in adult scabies (31.1%, P < .001) and pediatric scabies (39%, P < .01).

The number of prescriptions for lice and scabies also decreased significantly (P < .01) during the study period, although these numbers differed from the actual cases. Prescriptions decreased by 41.4%, 29.9%, and 69.3% for pediatric scabies, adult scabies, and pediatric lice, respectively.

Both pediatric scabies and pediatric lice showed a greater drop in prescriptions than in cases, while the drop in prescriptions for adult scabies was slightly less than the drop in cases.

The difference in the decreased numbers between cases and prescriptions may stem from the decrease in close contacts during the pandemic, which decreased the need for multiple prescriptions, but other potential explanations could be examined in future studies, the researchers wrote in their discussion.

The study findings were limited by several factors including the cross-sectional design and potential underdiagnosis and underreporting, as well as the focus only on a population in a single state, which may limit generalizability, the researchers noted.

However, the results offer preliminary insights on the impact of COVID-19 restrictions on scabies and lice, and suggest the potential value of physical distancing to reduce transmission of both conditions, especially in settings such as schools and prisons, to help contain future outbreaks, they concluded.

The study findings reinforce physical contact as the likely route of disease transmission, for lice and scabies, Sayed said in the interview. "It's possible distancing measures on a small scale could be considered for outbreaks in institutional settings, though the risks of these infestations are much lower than with COVID-19," he said. "It will be interesting to observe trends as physical distancing measures end to see if cases rebound in the next few years," he added.

Drop in Cases Likely Temporary

"Examining the epidemiology of different infectious diseases over time is an interesting and important area of study," said Sheilagh Maguiness, MD, associate professor of dermatology and pediatrics at the University of Minnesota, Minneapolis, who was asked to comment on the results.

"The pandemic dramatically altered the daily lives of adults and children across the globe, and we can learn a lot from studying how social distancing and prolonged masking has made an impact on the incidence and prevalence of different infectious illnesses in the country and across the world," she said in an interview.

Maguiness said she was not surprised by the study findings. "In fact, other countries have published similar studies documenting a reduction in both head lice and scabies infestations during the time of the pandemic," she said. "In France, it was noted that during March to December 2020, there was a reduction in sales for topical head lice and scabies treatments of 44% and 14%, respectively. Similarly, a study from Argentina documented a decline in head lice infestations by about 25% among children," she said.

"I personally noted a marked decrease in both of these diagnoses among children in my own clinic," she added.

"Since both of these conditions are spread through close physical contact with others, it makes sense that there would be a steep decline in ectoparasitic infections during times of social distancing. However, anecdotally we are now diagnosing and treating these infestations again more regularly in our clinic," said Maguiness. "As social distancing relaxes, I would expect that the incidence of both head lice and scabies will again increase."

The study received no outside funding. The researchers and Maguiness had no financial conflicts to disclose.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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