Healthcare workers have seen and suffered seemingly everything, but there is one creature as unnerving as the ragged screech of fingernails across a chalkboard: Sarcoptes scabiei hominis.
Imagine a parasitic creature crawling beneath the skin; consuming blood; laying eggs, leaving its byproducts; spreading to sensitive areas of the body; and creating serpentine, visible burrowing lines. The psychological aspects can be intense, troubling the mind with a singular thought: “It’s alive.”
It probably is for the best that transmissible mite scabies cannot be seen without a microscope or possibly a strong magnifying glass. Upon magnification, one can see a mite from class Arachnida. Yes, a cousin of the spider, with eight legs to prove it. Often misdiagnosed as other skin conditions, scabies can spread via skin-to-skin contact from infested patients to healthcare workers. The mites commonly infest areas like the webbing between the fingers; skin folds in elbows and knees; and the area surrounding the nipples, male genitalia, and the lower buttocks. Infested individuals can spread the mite to different sites on their own bodies through scratching that is said to be difficult to resist.
The cycle begins when a pregnant mite burrows beneath the skin, consuming blood and laying her eggs. The resulting adult mites can live anywhere from a month to six weeks. The first reaction in the host is primarily allergic, as the body responds to the presence of multiplying scabies, and rash and skin disruptions appear. This results in the intense itching that can lead to physical and mental detriments.
“This is really critical when thinking about what the incubation period [six weeks] for scabies within the host,” said Taylor Keck, MPH, an infection preventionist at UPMC Mercy Hospital in Pittsburgh. “Transmission occurs through close person-to-person contact and, less often, from fomite-to-person contact. Think of clothing or shared bedding — things like that.”
A Complex Case
Keck and colleague Marissa Durst BSN, RN, CIC, an IP at UPMC Mercy, recently spoke at the 2023 conference of the Association for Professionals in Infection Control and Epidemiology (APIC). They also coauthored a recently published paper on the scabies outbreak at UPMC, in which an undiagnosed patient exposed 46 healthcare workers in a “hands-on” rehabilitation unit.1
“The prevalence really seemed to be in our nursing and therapy colleagues, which makes a lot of sense,” Durst said. “They are with those patients, having prolonged contact care and are working with them to do their rehab. We have a shared therapy gym and a nutrition room. These patients could be in the hallways doing their therapy, so it’s really a communal setting.”
The index patient was a 70-year-old man admitted to the hospital from a correctional facility on Feb. 18, 2022, due to weakness of the right upper extremity caused by a fall.
“He had a very complex neurosurgical diagnosis, with a rash noted present on admission,” Keck explained. “He came to us and was diagnosed with discitis, vertebral osteomyelitis, and an epidural abscess. Subsequently, he had a secondary methicillin-sensitive Staphylococcus aureus bacteremia, requiring continuous oxacillin and operative management. The rash was actually suspected to worsen due to the continuous infusions of oxacillin.”
The patient underwent surgery and was transferred to the inpatient rehab unit on Feb. 25. The present-on-admission rash was worsening. Teledermatology was consulted, and the steroid prednisone was readministered. Two days later, the rash was rapidly worsening.
Triggered by the immune-compromising steroids, the skin rash erupted from a typical case of undiagnosed scabies into so-called “crusted” or Norwegian scabies. This means scabies already present in the patient multiplied rapidly due his decline in immune function, increasing to tens of thousands of mites and a raising the risk of transmission considerably.
“Persons with crusted scabies are very contagious and can spread the infestation easily both by direct skin-to-skin contact and by contamination of items such as their clothing, bedding, and furniture,” the CDC states. “Persons with crusted scabies should receive quick and aggressive medical treatment for their infestation to prevent outbreaks of scabies.”2
The patient was put in contact isolation with an emphasis on glove use and treated with oral ivermectin (200 mcg/kg) and topical permethrin 5%, the authors reported. Several treatments were required, which is not uncommon in severe scabies cases.
“All units were followed for the 6 weeks [incubation period] since diagnosis of the index patient,” Keck, Durst, and colleagues reported. “A total of 46 healthcare workers (20 nurses and 26 physical therapists) were exposed. Twenty-nine presented with symptoms and were treated with ivermectin and permethrin or only ivermectin.”1
The problem was the patient had been hospitalized for more than a week before the dramatic appearance of crusted scabies, exposing healthcare workers — who began to present with symptoms.
“These healthcare workers had visible rashes and other suspicious indications for disease,” Keck said. “They were really complaining of this horrible rash, itchiness.”
In addition to the symptomatic workers who were treated, there were about two dozen staff who reported contact with the patient but never developed symptoms.
High Anxiety
“We definitely had a high anxiety situation going on,” Keck noted. “We had healthcare workers who had nothing visible, they complained of a little itching, or they had one spot [of concern].”
Two of these workers expressed enough angst and anxiety that their requests for treatment were granted.
“There really wasn’t any concern that anything was brewing with them,” Keck said. “We talked about that high anxiety of staff. I cannot say that enough. They really just kept circling back. We weren’t visually seeing anything of concern, but they really just wanted that treatment. They wanted that ivermectin because it gives you that long-term coverage.”
Anxiety is common among scabies patients, considering disrupted sleep due to constant itching and the uneasy awareness that the body has been invaded by a living, moving parasite. The term “scabiophobia” has been coined to describe those with an extreme, irrational fear of the mites.
“Scabies morbidity could be linked to both clinical pathology and emotional elements of the disease,” researchers reported. “It should be kept in mind that patients diagnosed with scabies are affected not only clinically but also emotionally, and they can be consulted to psychiatry departments when necessary.”3
Scabies can contribute to depression and declining quality of life, partly because of the old myth that it is caused by a lack of hygiene, and the fact that it can be sexually transmitted. However, the primary contributor to spread is living in crowded conditions, where skin contact may occur, or common fomites and bed linens may spread scabies among family members.
No healthcare workers in the outbreak spread scabies to their families. However, Durst said there were a couple of outlier cases, including an “immunocompromised healthcare worker who we really had a lot of concern for. Her symptoms were a little bit more complex than what others were complaining about.”
The other case was a worker who left for maternity leave, but then developed scabies. “It was really all about managing the staff anxiety and them knowing that they were 100% supported and we would work through this with them as partners,” Durst said.
Blindsided by Infestation
The index patient was in a correctional facility with an ongoing scabies problem, but the hospital was not aware of that when the patient was admitted.
“There was a clear lack of communication between the correctional facility and our healthcare facility,” Keck said.
This created the opportunity for transmission during the time the patient’s rash went undiagnosed. “Everybody was on board — ID, dermatology,” Keck said. “They just couldn’t figure out what was going on with this patient. They thought it was a drug reaction rash.”
As physical therapy and employee health began reporting healthcare workers with apparent scabies, it became clear these were from early exposures before the appearance of the Norwegian rash and implementation of patient isolation.
“Before we even knew what was going on, we learned that healthcare workers may have been considered exposed back toward the end of February, with our first healthcare workers being confirmed with scabies from an outside dermatology visit on March 14,” Keck recalled.
Diagnoses were confirmed by a technique called skin scraping, and then microscopic examination.
“We also collaborated with our environmental services, focusing on enhanced cleaning of that unit to make sure those shared areas, shared equipment, [and] patient rooms were taken care of to mitigate any concern of spread,” Keck said.
Although it is off label to use ivermectin for scabies, Keck emphasized use of the drug in this case is not remotely like using it for COVID-19, which was primarily based on misinformation.
Regarding the use of ivermectin for the index patient and of the workers, the CDC stated: “Ivermectin is an oral antiparasitic agent approved for the treatment of worm infestations. Evidence suggests that oral ivermectin may be a safe and effective treatment for scabies. However, ivermectin is not FDA-approved for this use. The safety of ivermectin in children weighing less than 15 kg and in pregnant women has not been established.”4
FDA Cracks Down
Although the pandemic has largely abated, the authors of a recently published study revealed some physicians were touting the efficacy of ivermectin against COVID-19 and making other claims on social media counter to medical consensus.5 (For more information, see the related story in this issue.)
“Many physicians posted links or screenshots to articles claiming that ivermectin decreased mortality and hospitalization and increased time to recovery and viral clearance,” the authors reported. “Although some of the articles appeared to be peer-reviewed, none were in high-quality, peer-reviewed biomedical journals, and the FDA had not approved the use of these medications for treating COVID-19. At least one of the cited articles has been retracted due to misinterpretation of the data.”
In contrast, a comprehensive study analyzing published and preprint randomized, controlled trials (RCTs) on the effects of ivermectin on adult patients with COVID-19 revealed a profound lack of efficacy.
“Compared with the standard of care or placebo, ivermectin did not reduce all-cause mortality, length of stay, or viral clearance in RCTs in patients with mostly mild COVID-19,” the authors reported. “Ivermectin … is not a viable option to treat patients with COVID-19.”6
Armed with such information, the FDA is cracking down on websites that tout the availability of ivermectin to treat COVID-19. The agency sent a warning letter to a website called www.ivermectin4covid.com.
As of Aug. 28, 2023, the website has been suspended.
Scabies Toolkit for Healthcare
A scabies toolkit for healthcare facilities is available from the Long Beach (CA) Department of Health and Human Services. The document includes information on recognizing and reporting outbreaks as well as forms and checklists for investigation and discharging patients.
“Scabies outbreaks can result in significant direct and indirect costs related to outbreak investigation and control, public relations, and the discomfort and anxiety of patients, employees, and their family members,” the toolkit states. “In addition, scabies infestations can lead to common complications, such as bacterial skin infections. In severe cases, these infections can result in sepsis or even death.”8
Recommended tactics in the document include:
- Employee/occupational health policies for symptomatic healthcare workers;
- Access to an experienced scabies specialist or dermatologist to consult or assess complicated, unusual, severe, or persistent cases;
- Ongoing administrative and staff support for implementing scabies prevention, surveillance, identification, and control measures;
- Adequate access to evaluation, treatment, and staffing resources during an outbreak.
REFERENCES
- Xu T, Durst M, Keck T, et al. A scabies outbreak in an inpatient rehabilitation setting. Am J Infect Control 2023;51:705-709.
- Centers for Disease Control and Prevention. Scabies frequently asked questions (FAQs). Page last reviewed Sept. 1, 2020.
- Ali D. Impact of scabies on quality of life and correlation to depression and anxiety. Journal of Psychiatry. 2022.
- Centers for Disease Control and Prevention. Scabies medications. Page last reviewed Oct. 2, 2019.
- Sule S, DaCosta MC, DeCou E, et al. Communication of COVID-19 misinformation on social media by physicians in the US. JAMA Netw Open 2023;6:e2328928.
- Roman YM, Burela PA, Pasupuleti V, et al. Ivermectin for the treatment of coronavirus disease 2019: A systematic review and meta-analysis of randomized controlled trials. Clin Infect Dis 2022;74:1022-1029.
- U.S. Food and Drug Administration. Warning letter: www.ivermectin4covid.com. March 16, 2023.
- Long Beach Department of Health and Human Services. Scabies prevention & control: Toolkit for health care facilities. March 2021.
Healthcare workers have seen and suffered seemingly everything, but there is one creature as unnerving as the ragged screech of fingernails across a chalkboard: Sarcoptes scabiei hominis.
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