Diagnosis, treatment, and control of scabies: can we do better?

Infection Control among Healthcare Workers and Management of a Scabies Outbreak in a Large Italian University Hospital

This retrospective observational study describes the results of an ad-hoc designated prevention protocol aimed at containing the spread of the scabies infestation among healthcare workers (HCWs) of a large University Hospital in Italy. The outbreak started on October 2022 and a preventive protocol was set up thanks to a multidisciplinary approach. HCWs at high scabies risk were defined as subjects working in Operative Units with a scabies prevalence higher than 2%, close contacts of a confirmed case of scabies, or HCWs with signs and symptoms of the disease. All cases at high scabies risk underwent a dermatological examination, and the infested HCWs were suspended from work until definitive healing. Mass drug administration was established for all HCWs working in Operative Units with a scabies prevalence higher than 2%. Until March 2023, out of 183 screening dermatological examinations, 21 (11.5%) were diagnostic for scabies. Between 11 October 2022 (date of the first diagnosed scabies case) and 6 March 2023 (the end of incubation period related to the last case detected), the frequency of scabies was 0.35% (21 scabies cases/6000 HCWs). The duration of the outbreak in our hospital was 14.7 weeks. Statistical analysis shows a significant association between scabies and being a nurse and having an allergy to dust mites. We obtained a low frequency of scabies infection, limiting the duration of the outbreak and the related economic burden.

Scabies Knowledge Among Undergraduate Nursing Students in China: A Questionnaire Survey

PURPOSE

Scabies is a common, neglected, and a major health concern skin disease in the world. Improper care may produce a series of complications and even lead to the spread of diseases. Nursing students, as future health-care workers, are vital to the prevention and care of diseases. However, to date, few studies have focused on the basis of their disease cognition for scabies. This study aims to evaluate the level of undergraduate nursing students' awareness of scabies disease.

METHODS

A questionnaire survey was conducted among all undergraduate nursing students in Xi'an FanYi University, Xian, Shaanxi Province, China.

RESULTS

All the 132 undergraduate nursing students completed the questionnaire. The true ignorance rate of scabies in this survey was 82.6%. However, among the 56 students (42.4% of total) who thought they knew about the disease. Only 23 students (17.4% of the samples) had 75% or more satisfactory knowledge. Fewer students claimed that they had read about the itchy-mite-disease in books (N = 20, 15.2%). Compared with college textbooks (P-value < 0.05) and medical books (P-value < 0.05), other books (medical journals) provide more information about scabies. Nearly half of the students did not know that the scabies can be contagious. All students expressed their willingness to learn about scabies knowledge and participate in the diagnosis and treatment of scabies (100%).

CONCLUSION

This study shows that undergraduate nursing students have a poor level of knowledge about scabies. There is an urgent need to improve nursing students' awareness of scabies and increase their knowledge base, so as to strengthen the standardized nursing of scabies and reduce the prevalence of scabies.

Identification of Sarcoptes scabiei by Clinical Examination and Follow-up Examination in Medan City, Indonesia

Background: Scabies is a disease caused by the mite Sarcoptes scabiei var. hominis. In Indonesia, scabies ranks third out of the 12 most common skin diseases. In terms of disease screening, direct visualization of dermatitis from mites and microscopy of skin scrapings is less sensitive. PCR and dermoscopy examinations have a high sensitivity value to Sarcoptes mites. Aims: This study aims to identify Sarcoptes scabiei mites between clinical symptoms and supporting examinations, namely PCR and dermoscopy methods. Methods: This research is a cross-sectional study, with descriptive analytics. The number of samples of 50 people who met the inclusion criteria was examined by microscopic examination, dermoscopy, and PCR. We state it to be positive if we found scabies mites or their eggs on microscopy, delta wing sign, or jet wet contrail on dermoscopy and there is a 135bp DNA band on PCR. Results: 50 samples diagnosed with scabies based on cardinal sign of scabies, gender were 80% male and 20% female with an average age of 14 years. Based on the location of the rash, the most rashes were between the fingers and toes, each 26% and the least on the head as much as 2%. Based examination tools, no Sarcoptes scabiei mites were found through microscopic and dermoscopic examination, while the PCR examination found 12 positive samples of scabies. Conclusion: PCR examination is very sensitive and specific even in very small quantities, with the fore primer SSUDF and the reverse primer SSUDR. Further research is needed to assess the sensitivity and specificity of dermoscopy and PCR in diagnosing scabies.

The 2020 International Alliance for the Control of Scabies Consensus Criteria for the Diagnosis of Scabies

BACKGROUND

Scabies is a common parasitic skin condition that causes considerable morbidity globally. Clinical and epidemiological research for scabies has been limited by a lack of standardization of diagnostic methods.

OBJECTIVES

To develop consensus criteria for the diagnosis of common scabies that could be implemented in a variety of settings.

METHODS

Consensus diagnostic criteria were developed through a Delphi study with international experts. Detailed recommendations were collected from the expert panel to define the criteria features and guide their implementation. These comments were then combined with a comprehensive review of the available literature and the opinion of an expanded group of international experts to develop detailed, evidence-based definitions and diagnostic methods.

RESULTS

The 2020 International Alliance for the Control of Scabies (IACS) Consensus Criteria for the Diagnosis of Scabies include three levels of diagnostic certainty and eight subcategories. Confirmed scabies (level A) requires direct visualization of the mite or its products. Clinical scabies (level B) and suspected scabies (level C) rely on clinical assessment of signs and symptoms. Evidence-based, consensus methods for microscopy, visualization and clinical symptoms and signs were developed, along with a media library.

CONCLUSIONS

The 2020 IACS Criteria represent a pragmatic yet robust set of diagnostic features and methods. The criteria may be implemented in a range of research, public health and clinical settings by selecting the appropriate diagnostic levels and subcategories. These criteria may provide greater consistency and standardization for scabies diagnosis. Validation studies, development of training materials and development of survey methods are now required. What is already known about this topic? The diagnosis of scabies is limited by the lack of accurate, objective tests. Microscopy of skin scrapings can confirm the diagnosis, but it is insensitive, invasive and often impractical. Diagnosis usually relies on clinical assessment, although visualization using dermoscopy is becoming increasingly common. These diagnostic methods have not been standardized, hampering the interpretation of findings from clinical research and epidemiological surveys, and the development of scabies control strategies. What does this study add? International consensus diagnostic criteria for common scabies were developed through a Delphi study with global experts. The 2020 International Alliance for the Control of Scabies (IACS) Criteria categorize diagnosis at three levels of diagnostic certainty (confirmed, clinical and suspected scabies) and eight subcategories, and can be adapted to a range of research and public health settings. Detailed definitions and figures are included to aid training and implementation. The 2020 IACS Criteria may facilitate the standardization of scabies diagnosis.

Classic and Non-classic (Surrepticius) Scabies: Diagnostic and Treatment Considerations

The morphology of scabies, a mite infestation of worldwide proportion, is characterized by a variety of cutaneous lesions. Patients with classic scabies present with characteristic burrows often located on the web spaces of the fingers and toes. Scabies surrepticius refers to the non-classic atypical presentation of scabies; establishing the diagnosis of scabies in these individuals can be difficult. To facilitate the diagnosis of scabies, criteria have been proposed by the International Alliance for the Control of Scabies (IACS). These criteria are intended for scabies research; however, they can be utilized by clinicians to establish either a confirmed diagnosis, a clinical diagnosis or a suspected diagnosis of scabies. Visualization of mites, eggs or feces is necessary for a confirmed diagnosis of scabies. A clinical diagnosis can be established by observation of either genital lesions in men or burrows or classically distributed classical lesions in individuals with two historic features: pruritus and close contact with an individual who itches and has classically distributed classical scabetic lesions. The clinical features and management of a woman residing in an assisted living environment with a confirmed diagnosis of scabies and a man with a clinical diagnosis of scabies are described. The criteria for the suspected diagnosis of scabies require either one historic feature and typical lesions in a typical distribution or both historic features and the presence of atypical lesions or an atypical distribution of the skin lesions. Once the diagnosis of scabies is established, not only the patient but also close contacts should receive treatment with either a topical medication (such as permethrin 5% cream) or a systemic drug (ivermectin) or both. The number and frequency of treatments are variable; classic scabies typically is managed with a total of two treatments performed weekly to biweekly. Patients with crusted scabies usually require multiple topical and oral antiscabetic treatments in addition to topical keratolytic therapy. Bacterial impetiginization or infection (most commonly by Staphylococcus aureus or Streptococcus pyogenes) can complicate scabies infestation and potentially result in cellulitis, abscess, sepsis, rheumatic fever, rheumatic heart disease and post-streptococcal glomerulonephritis; therefore, in some patients, systemic antimicrobial therapy may be necessary in addition to scabies-directed treatment. In addition to systemic antihistamines, oral and/or topical corticosteroids may be used to provide symptomatic pruritus relief once the diagnosis of scabies has been established and mite-directed treatment has been initiated. The clinician should consider several potential causes (such as inadequate treatment, reinfection, mite resistance, delusions of parasitosis and the development of a new non-scabetic dermatosis) in scabies patients who fail to respond to treatment with a topical or oral scabicide therapy.

An Antibody Persistent and Protective Two rSsCLP-Based Subunit Cocktail Vaccine against Sarcoptes scabiei in a Rabbit Model

Scabies is a highly contagious disease caused by Sarcoptes scabiei which burrows into stratum corneum of host's skin. In this study, after optimizing vaccination schedule, a vaccination trial is comprised of three test groups of rabbits (n = 10/group) by immunization with (1) rSsCLP5; (2) rSsCLP12; or (3) a mixture of rSsCLP5 and rSsCLP12, three biological replicates groups (n = 10/group) and three control groups (n = 10/group). Levels of specific IgG, total IgE and cytokines in sera were detected and histopathologically analyzed as indicators of vaccine effects. The results showed that 85% (17/20) of rabbits exhibited no detectable skin lesions of S. scabiei infestation in mixed protein groups compared to single protein groups with 75% (15/20) and 70% (14/20), respectively. Moreover, the deworming rates of mixed groups are increased by 10%-20% compared with that of single groups. Each of six groups immunized with rSsCLP displayed significant increases of specific IgG, total IgE, IL-10, and TNF-α. The degree of skin damage in test groups also significantly lower than that of control groups. Thus, purified rSsCLP5 and rSsCLP12 subunit cocktail vaccine induced robust immune protection and could significantly decrease mite populations to reduce the direct transmission between rabbits.

Scabies: A Neglected Global Disease

BACKGROUND

Scabies is a skin disease caused by an obligate human parasite mite Sarcoptes scabiei var. hominis. Children under the age of two and elderly individuals are at the greatest risk. Knowledge of this condition is important for an early diagnosis to be made and treatment to be initiated.

OBJECTIVE

The review aimed to familiarize physicians with the clinical manifestations, diagnosis, evaluation, and management of scabies.

METHODS

A search was conducted using Pubmed with the built-in "Clinical Queries" tool. The search term "Scabies" was used. The categories of "epidemiology", "diagnosis", "therapy", "prevention" and "prognosis" had a limited scope for primary clinical studies. Meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews were included. Only papers published in the English language were included. A descriptive, narrative synthesis was provided of the retrieved articles.

RESULTS

Worldwide, scabies affects 200 to 300 million individuals annually. The average prevalence is estimated to be 5 to 10% in children of developing countries. Transmission usually occurs after close prolonged skin-to-skin contact. Classic scabies is characterized by an erythematous papular eruption, serpiginous burrows, and intense pruritus. Sites of predilection include the webs of the fingers, volar wrists, lateral aspects of fingers, extensor surfaces of elbows and knees, waist, navel, abdomen, buttocks, groins, and, genitals. A clinical diagnosis of classic scabies can be made on the basis of the history and clinical findings. Other clinical variants include crusted scabies, nodular scabies, and bullous scabies. Finding the mite, ova, or fecal pellets on microscopic examination of scrapings taken from skin lesions confirms the diagnosis of scabies infestation. For eradication of scabies mites, the drugs of choice are topical permethrin and oral ivermectin.

CONCLUSION

Scabies is a highly contagious parasitic cutaneous disease that is stigmatising and debilitating. Increased awareness, accurate diagnosis, and prompt treatment are essential for the effective control of scabies and for the prevention of the spread of the disease.

The public health control of scabies: priorities for research and action

Scabies is a parasitic disease of the skin that disproportionately affects disadvantaged populations. The disease causes considerable morbidity and leads to severe bacterial infection and immune-mediated disease. Scientific advances from the past 5 years suggest that scabies is amenable to population-level control, particularly through mass drug administration. In recognition of these issues, WHO added scabies to the list of neglected tropical diseases in 2017. To develop a global control programme, key operational research questions must now be addressed. Standardised approaches to diagnosis and methods for mapping are required to further understand the burden of disease. The safety of treatments for young children, including with ivermectin and moxidectin, should be investigated. Studies are needed to inform optimum implementation of mass treatment, including the threshold for intervention, target, dosing, and frequency. Frameworks for surveillance, monitoring, and evaluation of control strategies are also necessary.