J Korean Med Sci.  2025 Jan;40(3):e7. 10.3346/jkms.2025.40.e7.

Management of a Large Nosocomial Outbreak From an Index of Crusted Scabies in a Tertiary Care Hospital, 2023: A Retrospective Observational Study

• Jung J
• Kim SK
• Kim EO
• Choi EJ
• Choi J
• Chang Z
• Chang SE
• Won CH
• Kim SH

• KMID: 2564227
• DOI: http://doi.org/10.3346/jkms.2025.40.e7

Abstract

Background
In 2023, we experienced an outbreak from a case of undiagnosed crusted scabies, resulting in a significant number of exposed individuals and secondary cases. In this report, we describe the outbreak control measures, the attack rate, and the risk factors for acquisition of scabies among healthcare workers (HCWs).
Methods
This study was conducted in a 2,700-bed tertiary care hospital in Seoul, South Korea. The attack rate was defined both for microscopic proven cases per exposed individuals and as the sum of proven and probable cases per exposed individuals. Outbreak control measures included identifying and treating all potentially exposed individuals with or without symptoms, as well as environmental disinfection.
Results
From the index, there was potential quinary transmission resulting in 63 proven cases, 142 probable cases, and a total of 1,820 exposed individuals, including 734 contacts from the index case. The attack rate from the index was 7% (50/734) based on proven cases and 19% (138/734) based on proven and probable cases. Among the 526 HCWs who received preemptive topical treatment with permethrin applied once, 21 (4%) were later diagnosed as scabies. In addition, 5 of 20 HCWs (25%) with initial proven scabies had a persistent positive microscopic exam after four permethrin treatments. In the case group, there were significantly more nurses (60% vs. 43%, P = 0.007) and nurse assistants (20% vs. 9%, P = 0.006). There were significantly more cases than controls involving direct contact with the index case (94% vs. 64%, P < 0.001).
Conclusion
Lowering the threshold for suspicion of crusted scabies is important, as a single missed case could lead to a large outbreak. Simultaneously applying preemptive permethrin cream to all potentially exposed individuals might have been effective in preventing further transmission. However, caution is needed because the development of scabies or persistent scabies is possible even with preemptive or therapeutic treatment.

Keyword

Crusted Scabies; Outbreak Control; Permethrin; Attack Rate; Tertiary Hospital

Figure

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  Fig. 1 Timeline of the hospital course of the index patient.DER = dermatology clinic, ER = emergency room, LTCF = long-term care facility, MICU = medical intensive care unit, Adm = admission, GIST = gastrointestinal stromal tumor, PO = per os, CSP = cyclosporine, DRESS = drug reaction with eosinophilia and systemic symptoms.

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  Fig. 2 Gross skin lesions of the index patient on the day of admission. A generalized scaly, lichenified skin rash was present all over his body. (A) Skin lesions around the right hip; (B) Skin lesions on the trunk.

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  Fig. 3 Epidemic curve. (A) Epidemic curve based on proven cases only. (B) Epidemic curve including both proven and probable cases.

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  Fig. 4 Transmission. There was possible quinary transmission from the index case. Dashed line indicates that no direct contact with cases.

Reference

1. Chosidow O. Scabies. N Engl J Med. 2006; 354:1718–1727. PMID: 16625010.

2. Salavastru CM, Chosidow O, Boffa MJ, Janier M, Tiplica GS. European guideline for the management of scabies. J Eur Acad Dermatol Venereol. 2017; 31(8):1248–1253. PMID: 28639722.

3. Walter B, Heukelbach J, Fengler G, Worth C, Hengge U, Feldmeier H. Comparison of dermoscopy, skin scraping, and the adhesive tape test for the diagnosis of scabies in a resource-poor setting. Arch Dermatol. 2011; 147(4):468–473. PMID: 21482897.

4. Cho M, Kim HS. Crusted scabies in a patient with intellectual disability. J Korean Med Sci. 2022; 37(19):e151. PMID: 35578583.

5. Mounsey KE, Murray HC, King M, Oprescu F. Retrospective analysis of institutional scabies outbreaks from 1984 to 2013: lessons learned and moving forward. Epidemiol Infect. 2016; 144(11):2462–2471. PMID: 27019288.

6. Jung J, Lee WJ, Chang SE, Kim SH. Scabies outbreaks in care homes for the elderly. Lancet Infect Dis. 2018; 18(12):1309–1310. PMID: 30507452.

7. Kim M, Kim SK, Hong MJ, Kwak SH, Kim EO, Bae M, et al. Importance of follow-up microscopic examination in hospitalized patients with confirmed scabies. Am J Trop Med Hyg. 2020; 103(6):2539–2541. PMID: 32996448.

8. Bouvresse S, Chosidow O. Scabies in healthcare settings. Curr Opin Infect Dis. 2010; 23(2):111–118. PMID: 20075729.

9. Hasan T, Krause VL, James C, Currie BJ. Crusted scabies; a 2-year prospective study from the Northern Territory of Australia. PLoS Negl Trop Dis. 2020; 14(12):e0008994. PMID: 33338053.

10. Andersen BM, Haugen H, Rasch M, Heldal Haugen A, Tageson A. Outbreak of scabies in Norwegian nursing homes and home care patients: control and prevention. J Hosp Infect. 2000; 45(2):160–164. PMID: 10860693.

11. Buehlmann M, Beltraminelli H, Strub C, Bircher A, Jordan X, Battegay M, et al. Scabies outbreak in an intensive care unit with 1,659 exposed individuals--key factors for controlling the outbreak. Infect Control Hosp Epidemiol. 2009; 30(4):354–360. PMID: 19254159.

12. Clark J, Friesen DL, Williams WA. Management of an outbreak of Norwegian scabies. Am J Infect Control. 1992; 20(4):217–220. PMID: 1381877.

13. Hsueh PR, Lin BH, Hwang CC, Hsieh BL, Liu JC, Lin M. Nosocomial outbreak of scabies. J Formos Med Assoc. 1992; 91(2):228–232. PMID: 1364225.

14. Khan A, O’Grady S, Muller MP. Rapid control of a scabies outbreak at a tertiary care hospital without ward closure. Am J Infect Control. 2012; 40(5):451–455. PMID: 21868131.

15. Belvisi V, Orsi GB, Del Borgo C, Fabietti P, Ianari A, Albertoni F, et al. Large nosocomial outbreak associated with a Norwegian scabies index case undergoing TNF-α inhibitor treatment: management and control. Infect Control Hosp Epidemiol. 2015; 36(11):1358–1360. PMID: 26288185.

16. Boyer PH, Deboscker S, Hernandez C, Ramsheyi M, Schneider P, Foeglé J, et al. An undiagnosed index case leading to a nosocomial scabies outbreak: how mass single-dose ivermectin treatment can help control a nosocomial epidemic. Infect Control Hosp Epidemiol. 2018; 39(5):631–632. PMID: 29457578.

17. Utsumi M, Makimoto K, Quroshi N, Ashida N. Types of infectious outbreaks and their impact in elderly care facilities: a review of the literature. Age Ageing. 2010; 39(3):299–305. PMID: 20332371.

18. Leistner R, Buchwald D, Beyer M, Philipp S. Scabies outbreak among healthcare workers in a German acute care hospital. J Infect Prev. 2017; 18(4):189–192. PMID: 28989526.

19. Kim DH, Kim Y, Yun SY, Yu HS, Ko HC, Kim M. Risk factors for scabies in hospital: a systematic review. BMC Infect Dis. 2024; 24(1):353. PMID: 38575893.