Risk factors for delayed diagnosis of scabies in hospitalized patients from long-term care facilities

Increase of scabies infestations, Norway, 2006 to 2018

Between October and December 2018, several clinicians in Norway reported an increase in scabies diagnoses. We compared data from the Norwegian Syndromic Surveillance System on medical consultations for mite infestations with scabies treatment sales data to investigate this reported increase. From 2013 to 2018, consultations and sales of scabies treatments had almost increased by threefold, particularly affecting young adults 15–29 years. We recommend to increase awareness among clinicians to ensure timely diagnosis and treatment.

Epidemiologic Trends and Seasonality of Scabies in South Korea, 2010-2017

Scabies is a parasitic skin infection with intense itching. Scabies infection seriously impairs quality of life, while outbreaks in medical institutions cause financial losses. This study aimed to present the annual and seasonal trend of prevalence of scabies in the national population. Scabies cases were extracted from National Health Insurance Service database and its epidemiologic characteristics were assessed. To analyze the seasonality of scabies occurrence, temperature and humidity were included in the model as weather factors, and the per capita gross national income index was adjusted. The annual prevalence by age group was 0.56-0.69 per 1,000 persons until the age of 40 years and peaked at 3.0-4.1 per 1,000 persons in the age group over 80 years. The number of women diagnosed with scabies has been consistently higher compared to that of men since 2010. Mean number of cases diagnosed as scabies was lowest in spring, approximately 4,000 cases, when the average temperature was less than 5°C at 2 months prior, whereas more than 6,000 scabies cases occurred in autumn when temperatures exceeded 25°C at 2 months prior. This study presents the epidemiological characteristics and seasonality of all cases nationwide over 8 years and will help to establish control policies.

Scabies and risk of skin sores in remote Australian Aboriginal communities: A self-controlled case series study

Background

Skin sores caused by Group A streptococcus (GAS) infection are a major public health problem in remote Aboriginal communities. Skin sores are often associated with scabies, which is evident in scabies intervention programs where a significant reduction of skin sores is seen after focusing solely on scabies control. Our study quantifies the strength of association between skin sores and scabies among Aboriginal children from the East Arnhem region in the Northern Territory.

Methods and results

Pre-existing datasets from three published studies, which were conducted as part of the East Arnhem Healthy Skin Project (EAHSP), were analysed. Aboriginal children were followed from birth up to 4.5 years of age. Self-controlled case series design was used to determine the risks, within individuals, of developing skin sores when infected with scabies versus when there was no scabies infection. Participants were 11.9 times more likely to develop skin sores when infected with scabies compared with times when no scabies infection was evident (Incidence Rate Ratio (IRR) 11.9; 95% CI 10.3–13.7; p<0.001), and this was similar across the five Aboriginal communities. Children had lower risk of developing skin sores at age ≤1 year compared to at age >1 year (IRR 0.8; 95% CI 0.7–0.9).

Conclusion

The association between scabies and skin sores is highly significant and indicates a causal relationship. The public health importance of scabies in northern Australia is underappreciated and a concerted approach is required to recognise and eliminate scabies as an important precursor of skin sores.

Skin sores, also known as impetigo, are highly contagious bacterial skin infections, which are found commonly in school children and occasionally in adults. Skin sores are prevalent in disadvantaged or resource-poor settings. In Australia, about two thirds of Aboriginal children suffer from skin sores by their first birthday. If untreated or treated poorly, skin sores can eventually cause heart and kidney problems. It is also believed that scabies, another common skin infection in Aboriginal children, can increase the risk of developing skin sores by allowing the bacteria to enter the skin more easily through breaks in the skin. Our research explored the following: if scabies is a risk factor for skin sores then what is the strength of the association between the two conditions.

Scabies outbreak among healthcare workers in a German acute care hospital

BACKGROUND

This article reports on a scabies outbreak among healthcare workers (HCW) in an acute care hospital. The outbreak was associated with a patient suffering from a chronic skin disease that was later diagnosed as crusted scabies.

OBJECTIVE

The objective was to determine the outbreak drivers and define a prevention strategy against future outbreaks.

METHODS

All staff that had contact with the patient were treated with 5% permethrin ointment. An interdisciplinary outbreak investigation team was established. The team conducted a questionnaire-based case-control study.

FINDINGS

After the permethrin treatment, no further case was found. Twenty-seven HCWs who had contact with the index patient answered the questionnaire (response rate 73%). The outbreak questionnaire revealed 13 cases of secondary scabies among HCWs. In the multivariable analysis, a lack of glove use (odds ratio [OR], 9.8; P value = 0.036) and frequent close physical contact (OR, 8.151; P value = 0.038) were associated with increased risk of scabies acquisition.

DISCUSSION

The scabies outbreak was most likely driven by three factors: an index patient with crusted scabies; a delayed diagnosis of this patient; and close physical contact without gloves during his hospital stay. The use of disposable gloves for patients with unclear dermatological diagnosis have the potential to limit future scabies outbreaks.

Enigmatic pruritus in a kidney transplant patient

Pruritus is a common problem following a kidney transplant and is usually attributable to new medications related to transplantation. We present an unusual case of pruritus that began several months after kidney transplantation. After changing several immunosuppressive medications, numerous clinical visits and consideration by the patient of stopping immunosuppression, scabies was diagnosed as the cause. Treatment with oral ivermectin and topical permethrin resulted in complete resolution of symptoms within 1 week. Transplant physicians should consider common causes of pruritus unrelated to transplantation; diagnostic skin lesions of scabies may be absent.

Development of Conventional and Real-Time Quantitative PCR Assays for Diagnosis and Monitoring of Scabies

Scabies remains the most prevalent, endemic, and neglected ectoparasitic infestation globally and can cause institutional outbreaks. The sensitivity of routine microscopy for demonstration of Sarcoptes scabiei mites or eggs in skin scrapings is only about 50%. Except for three studies using conventional or two-tube nested PCR on a small number of cases, no systematic study has been performed to improve the laboratory diagnosis of this important infection. We developed a conventional and a real-time quantitative PCR (qPCR) assay based on the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of S. scabiei. The cox1 gene is relatively well conserved, with its sequence having no high levels of similarity to the sequences of other human skin mites, pathogenic zoonotic mites, or common house dust mite species. This mitochondrial gene is also present in large quantities in arthropod cells, potentially improving the sensitivity of a PCR-based assay. In our study, both assays were specific and were more sensitive than microscopy in diagnosing scabies, with positive and negative predictive values of 100%. The S. scabiei DNA copy number in the microscopy-positive specimens was significantly higher than that in the microscopy-negative specimens (median S. scabiei DNA copy number, 3.604 versus 2.457 log10 copies per reaction; P = 0.0213). In the patient with crusted scabies, the qPCR assay performed on lesional skin swabs instead of scrapings revealed that the parasite DNA load took about 2 weeks to become negative after treatment. The utility of using lesional skin swabs as an alternative sample for diagnosis of scabies by PCR should be further evaluated.

Scabies in the nursing home

Scabies infection is antediluvian and ubiquitous both in developing and developed countries, yet often neglected. Scabies has a predilection to infect vulnerable subsets of population in crowding conditions, typically applicable to residents in the nursing home. The mite incites a unique immunological response from human hosts. Scabies does not manifest as a singular skin condition and may present atypically in older adults, the majority of nursing home residents, where delay has deleterious consequences. Further, pruritus or itching, the hallmark of scabies infection, is a common complaint from a variety of causes among older adults. Hence, the diagnosis is often delayed or missed. There are several pharmacological treatment options; long-term care practitioners need to understand the characteristics of each agent before selection. Even more relevant is the importance of nonpharmacological aspects of management, crucial in the success of averting spread or outbreaks in long-term care settings.