A novel clinical grading scale to guide the management of crusted scabies

Scabies: a clinical update

Scabies is the most common neglected tropical disease with cutaneous manifestations, disproportionately affecting socially disadvantaged populations living in overcrowded settings. Scabies infestation is characterised by a generalised intractable pruritus, and is often complicated by secondary bacterial infection, which can lead to a range of complications. Scabies is a clinical diagnosis and requires an adequate degree of suspicion. The use of dermoscopy may improve diagnostic accuracy. In Australia, the first-line treatment recommended for scabies is topical permethrin 5% cream, applied to the whole body and repeated in one week. Oral ivermectin is subsidised by the Pharmaceutical Benefits Scheme with streamlined authority for patients who have completed and failed treatment with topical therapy, have a contraindication to topical treatment or have crusted scabies. Early identification and prompt initiation of treatment is key to minimise the disease burden of scabies.

Scabies

Scabies is one of the most common and highest-burden skin diseases globally. Estimates suggest that >200 million people worldwide have scabies at any one time, with an annual prevalence of 455 million people, with children in impoverished and overcrowded settings being the most affected. Scabies infection is highly contagious and leads to considerable morbidity. Secondary bacterial infections are common and can cause severe health complications, including sepsis or necrotizing soft-tissue infection, renal damage and rheumatic heart disease. There is no vaccine or preventive treatment against scabies and, for the past 30 years, only few broad-spectrum antiparasitic drugs (mainly topical permethrin and oral ivermectin) have been widely available. Treatment failure is common because drugs have short half-lives and do not kill all developmental stages of the scabies parasite. At least two consecutive treatments are needed, which is difficult to achieve in resource-poor and itinerant populations. Another key issue is the lack of a practical, rapid, cheap and accurate diagnostic tool for the timely detection of scabies, which could prevent the cycle of exacerbation and disease persistence in communities. Scabies control will require a multifaceted approach, aided by improved diagnostics and surveillance, new treatments, and increased public awareness.

A systematic review of immunosuppressive risk factors and comorbidities associated with the development of crusted scabies

OBJECTIVES

Crusted scabies (CS, Norwegian scabies) is a severe form of scabies, characterized by hyper-infestation of Sarcoptes scabiei mites. CS is commonly associated with immunosuppression but is also reported in overtly immunocompetent individuals. We reviewed immunosuppressive risk factors and comorbidities associated with CS.

METHODS

The National Library of Medicine (PubMed) database was reviewed for patient case reports of CS from January 1998 to July 2023. Two authors screened records for eligibility, extracted data, and one critically appraised the quality of the studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023466126.

RESULTS

A total of 436 records were identified, of which 204 were included for systematic review. From these, 683 CS patients were included. CS impacted both genders equally. Adults (21-59 years) were more commonly affected (45.5%) compared to children (0-20 years, 21%). Corticosteroid use was the most prevalent immunosuppressive risk factor identified (27.7% of all cases). About 10.2% of reports were associated with HIV/AIDS, and 8.5% with HTLV-1 infection. 10.5% of patients were overtly immunocompetent with no known risk factors. Overall, 41 (6.0%) died, many subsequent to secondary bacteremia.

CONCLUSION

This study represents the first systematic review undertaken on immunosuppressive risk factors associated with CS. This provides insights into trends of immunosuppression and mechanisms of CS development.

Scabies: Immunopathogenesis and pathological changes

Scabies is an itchy skin disease caused by the burrowing mite Sarcoptes scabiei. During their lifespan, the female mites invade the stratum corneum and create tunnels, in which they reside, move, feed, deposit fecal pellets, and lay eggs. Recently, scabies was included in the World Health Organization roadmap for neglected tropical diseases 2021-2030. This review attempts to summarize our knowledge about the mite's biology and the disease pathogenesis, pathological changes, and complications. Generally, the host-parasite interaction in scabies is highly complex and involves different mechanisms, some of which are yet largely unknown. Elucidation of the nature of such interaction as well as the underlying mechanisms could allow a better understanding of the mite's biology and the development of novel diagnostic and therapeutic options for scabies control programs. Moreover, identification of the molecular basis of such interaction could unveil novel targets for acaricidal agents and vaccines.

HIV and skin infections

HIV infection alters the skin microbiome and predisposes to a wide range of cutaneous infections, from atypical presentations of common skin infections to severe disseminated infections involving the skin that are AIDS-defining illnesses. Bacterial infection of the skin, most commonly caused by Staphylococcus aureus, occurs frequently and can result in bacteremia. Nontuberculous mycobacterial infections that are usually localized to the skin may disseminate, and guidance on the treatment of these infections is limited. Herpes simplex can be severe, and less common presentations such as herpetic sycosis and herpes vegetans have been reported. Severe herpes zoster, including disseminated infection, requires intravenous antiviral treatment. Viral warts can be particularly difficult to treat, and in atypical or treatment-resistant cases a biopsy should be considered. Superficial candidosis occurs very commonly in people living with HIV, and antifungal resistance is an increasing problem in non-albicans Candida species. Systemic infections carry a poor prognosis. In tropical settings the endemic mycoses including histoplasmosis are a problem for people living with HIV, and opportunistic infections can affect those with advanced HIV in all parts of the world. Most cutaneous infections can develop or worsen as a result of immune reconstitution in the weeks to months after starting antiretroviral therapy. Direct microscopic examination of clinical material can facilitate rapid diagnosis and treatment initiation, although culture is important to provide microbiological confirmation and guide treatment.

Pharmacokinetic and pharmacodynamic considerations for treating sarcoptic mange with cross-relevance to Australian wildlife

Sarcoptes scabiei is the microscopic burrowing mite responsible for sarcoptic mange, which is reported in approximately 150 mammalian species. In Australia, sarcoptic mange affects a number of native and introduced wildlife species, is particularly severe in bare-nosed wombats (Vombatus ursinus) and an emerging issue in koala and quenda. There are a variety of acaricides available for the treatment of sarcoptic mange which are generally effective in eliminating mites from humans and animals in captivity. In wild populations, effective treatment is challenging, and concerns exist regarding safety, efficacy and the potential emergence of acaricide resistance. There are risks where acaricides are used intensively or inadequately, which could adversely affect treatment success rates as well as animal welfare. While reviews on epidemiology, treatment strategies, and pathogenesis of sarcoptic mange in wildlife are available, there is currently no review evaluating the use of specific acaricides in the context of their pharmacokinetic and pharmacodynamic properties, and subsequent likelihood of emerging drug resistance, particularly for Australian wildlife. This review critically evaluates acaricides that have been utilised to treat sarcoptic mange in wildlife, including dosage forms and routes, pharmacokinetics, mode of action and efficacy. We also highlight the reports of resistance of S. scabiei to acaricides, including clinical and in vitro observations.

Severe Scabies: A French Multi-centre Study Involving 95 Patients with Crusted and Profuse Disease and Review of the Literature

The aim of this multi-centre French retrospective study was to identify severe, i.e. crusted and profuse, scabies patients. Records were retrieved from 22 Dermatology or Infectious Diseases departments in the Ile-de-France from January 2009 to January 2015 to characterize epidemiology, demography, diagnosis, contributing factors, treatment features, and outcomes in severe scabies. A total of 95 inpatients (57 crusted and 38 profuse) were included. A higher number of cases was observed among elderly patients (>75 years), mostly living in institutions. Thirteen patients (13.6%) reported a history of previously treated scabies. Sixty-three patients (66.3%) had been seen by a previous practitioner for the current episode (up to 8 previous visits). Initial misdiagnosis (e.g. eczema, prurigo, drug-related eruptions, psoriasis) was documented in 41 patients (43.1%). Fifty-eight patients (61%) had already received 1 or more previous treatments for their current episode. Forty percent received corticosteroids or acitretin for an initial diagnosis of eczema or psoriasis. Median time from the onset of symptoms to the diagnosis of severe scabies was 3 months (range 0.3-22). Itch was present in all patients at diagnosis. Most patients (n=84, 88.4%) had comorbidities. Diagnostic and therapeutic approaches varied. Complications occurred in 11.5% of cases. To date, there is no consensus for diagnosis and treatment, and future standardization of is required for optimal management.

Crusted Hyperkeratotic Scabies: A Case Report

Crusted scabies is a rare form of classic scabies characterized by severe symptoms, mainly observed in immunosuppressed patients. This disease has been associated with a variety of health problems, such as delayed diagnosis, infection risk, and high mortality, mainly from sepsis. We report the case of a patient with hyperkeratotic scabies in the context of immunosuppression associated with malnutrition and the use of topical corticosteroids. Ivermectin is critical for successfully treating crusted scabies. However, a higher cure rate has been reported with the combination of oral ivermectin and topical permethrin. In our study, we chose to use a plan suitable for grade two scabies, resulting in a subtotal regression of the lesions. Crusted scabies is a highly contagious parasitic cutaneous disease, and there are few reports in the national and international literature. It is necessary to suspect this presentation form in order to establish a timely diagnosis and detect and treat associated comorbidities.

Spinosad topical suspension (0.9%): a new topical treatment for scabies

INTRODUCTION

Scabies is a highly contagious skin disease caused by the parasitic mite Sarcoptes scabiei. There is no vaccine and for the past 30 years, the first line treatments have been topical permethrin and oral ivermectin. These drugs target mainly the parasite nervous system, killing only the motile stages. As they lack ovicidal activities, repeat treatments are required to achieve complete cure. Incompliance to repeat treatments causing prolonged drug usage, has contributed to emerging drug resistances. In addition, they are not appropriate for all patient categories, specifically for infants and young children or pregnant and breast feeding women. Consequently, new single dose scabicides are urgently needed.

AREAS COVERED

In 2021, spinosad, a drug previously used to treat head lice, was approved by the US FDA as a topical scabies treatment. Here the pharmacology, clinical efficacy and tolerability of this drug are discussed.

EXPERT OPINION

As the first single dose scabicide the formulated 0.9% topical Spinosad solution shows significant efficacy, little systemic absorption and no serious adverse reactions, making it a promising treatment for classical scabies in patients older than four years.

Crusted scabies in AIDS patient, a clinical challenge to be sorted out with a simple bedside test

Norwegian or crusted scabies is a highly contagious severe variant of scabies described first among leprosy patients in Norway in 1848 by Boeck and Danielsen. Herein, we report a case of crusted scabies in an AIDS patient with large hyperpigmented macules covered with thick crusts present over the axilla, inguinal region, and gluteal region. Treatment started immediately with ivermectin, permethrin, and keratolytics after doing KOH microscopy. Mite population may exceed 1 million/person. Hence, it is highly infectious and can set off epidemics of scabies in home or institutions.

Crusted Scabies, a Neglected Tropical Disease: Case Series and Literature Review

Crusted scabies is a rare form of scabies that presents with more severe symptoms than those of classic scabies. It is characterized by large crusted lesions, extensive scales, thick hyperkeratosis, and contains a large number of highly contagious itch mites. Crusted scabies is more prevalent in immunocompromised, malnourished, and disabled individuals. This disease has been linked to a variety of health problems, including delayed diagnosis, infection risk, and high mortality, mainly from sepsis, and it has the potential to cause an outbreak due to its hyper-infestation, which makes it highly infectious. This article reports three cases of crusted scabies in North Sulawesi, Indonesia. Recent updates and a comprehensive review of the literature on the disease are also included, emphasizing the critical importance of early diagnosis and effective medical management of patients, which are necessary to prevent the complications and spread in communities.

Health care cost of crusted scabies in Aboriginal communities in the Northern Territory, Australia

Background

Crusted scabies is a debilitating dermatological condition. Although still relatively rare in the urban areas of Australia, rates of crusted scabies in remote Aboriginal communities in the Northern Territory (NT) are reported to be among the highest in the world.

Objective

To estimate the health system costs associated with diagnosing, treating and managing crusted scabies.

Methods

A disease pathway model was developed to identify the major phases of managing crusted scabies. In recognition of the higher resource use required to treat more severe cases, the pathway differentiates between crusted scabies severity grades. The disease pathway model was populated with data from a clinical audit of 42 crusted scabies patients diagnosed in the Top-End of Australia’s Northern Territory between July 1, 2016 and May 1, 2018. These data were combined with standard Australian unit costs to calculate the expected costs per patient over a 12-month period, as well as the overall population cost for treating crusted scabies.

Findings

The expected health care cost per patient diagnosed with crusted scabies is $35,418 Australian dollars (AUD) (95% CI: $27,000 to $43,800), resulting in an overall cost of $1,558,392AUD (95% CI: $1,188,000 to $1,927,200) for managing all patients diagnosed in the Northern Territory in a given year (2018). By far, the biggest component of the health care costs falls on the hospital system.

Discussion

This is the first cost-of-illness analysis for treating crusted scabies. Such analysis will be of value to policy makers and researchers by informing future evaluations of crusted scabies prevention programs and resource allocation decisions. Further research is needed on the wider costs of crusted scabies including non-financial impacts such as the loss in quality of life as well as the burden of care and loss of well-being for patients, families and communities.

Crusted scabies is characterised by thick skin crusting and fissuring and can lead to serious secondary infections and death from complications. Rates of crusted scabies in remote Aboriginal communities in the Northern Territory (NT) are among the highest in the world. Efforts are on the way in Australia to prevent, if not eliminate, crusted scabies. We use data from a clinical audit of 42 patients diagnosed with crusted scabies in the Top-End of the NT to estimate the health system costs associated with diagnosing, treating and managing crusted scabies for patients and their households. This cost of illness study can provide a valuable starting point for policy makers and evaluators in estimating the potential economic impact of crusted scabies prevention programs on health care service use and costs.

First Description of the Composition and the Functional Capabilities of the Skin Microbial Community Accompanying Severe Scabies Infestation in Humans

Epidemiological studies link Sarcoptes scabiei infection and impetigo. Scabies mites can promote Streptococcus pyogenes (Group A Streptococcus) and Staphylococcus aureus infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. However, little is known about the composition and the function of the scabies-associated microbiota. Here, high-throughput whole-metagenome sequencing was used to explore the scabies-associated microbiome. Scabies mites including their immediate microenvironments were isolated from two patients with severe scabies in Northern Australia. Two ~45–50 million paired-end reads Illumina libraries were generated of which ~2 (5.1%) and 0.7 million (1.3%) microbial reads were filtered out by mapping to human (hg19) and mite draft genomes. Taxonomic profiling revealed a microbial community dominated by the phylum Firmicutes (A: 79% and B: 59%) and genera that comprise Streptococcus, Staphylococcus, Acinetobacter, and Corynebacterium. Assembly of the metagenome reads resulted in genome bins representing reference genomes of Acinetobacter baumannii, Streptococcus dysgalactiae (Group C/G), Proteus mirablis and Staphylococcus aureus. The contigs contained genes relevant to pathogenicity and antibiotics resistance. Confocal microscopy of a patient skin sample confirmed A. baumannii, Streptococci and S. aureus in scabies mite gut and faeces and the surrounding skin. The study provides fundamental evidence for the association of opportunistic pathogens with scabies infection.

Recent advances in understanding and treating scabies

Scabies is an infestation of the skin caused by the mite Sarcoptes scabiei. In 2017, scabies was recognised by the World Health Organisation as a disease of public importance and was consequently added to the list of neglected tropical diseases. An estimated 200 million people currently have scabies worldwide. Scabies is endemic in many developing countries, with the highest prevalence being in hot, humid climates such as the Pacific and Latin American regions. Scabies causes a host immune response which is intensely itchy. Scratching of the lesions can lead to secondary bacterial infections of the skin, such as impetigo, most commonly caused by Streptococcus pyogenes or Staphylococcus aureus. This can have fatal consequences, such as septicaemia, glomerulonephritis, and rheumatic heart disease. Advances over the past 5 years indicate that mass drug administration is an effective strategy to treat scabies. This review will outline advances in the mite biology, epidemiological understanding, diagnosis, and treatment of scabies.

Molecular diagnosis of scabies using a novel probe-based polymerase chain reaction assay targeting high-copy number repetitive sequences in the Sarcoptes scabiei genome

Background

The suboptimal sensitivity and specificity of available diagnostic methods for scabies hampers clinical management, trials of new therapies and epidemiologic studies. Additionally, parasitologic diagnosis by microscopic examination of skin scrapings requires sample collection with a sharp scalpel blade, causing discomfort to patients and difficulty in children. Polymerase chain reaction (PCR)-based diagnostic assays, combined with non-invasive sampling methods, represent an attractive approach. In this study, we aimed to develop a real-time probe-based PCR test for scabies, test a non-invasive sampling method and evaluate its diagnostic performance in two clinical settings.

Methodology/Principal findings

High copy-number repetitive DNA elements were identified in draft Sarcoptes scabiei genome sequences and used as assay targets for diagnostic PCR. Two suitable repetitive DNA sequences, a 375 base pair microsatellite (SSR5) and a 606 base pair long tandem repeat (SSR6), were identified. Diagnostic sensitivity and specificity were tested using relevant positive and negative control materials and compared to a published assay targeting the mitochondrial cox1 gene. Both assays were positive at a 1:100 dilution of DNA from a single mite; no amplification was observed in DNA from samples from 19 patients with other skin conditions nor from house dust, sheep or dog mites, head and body lice or from six common skin bacterial and fungal species. Moderate sensitivity of the assays was achieved in a pilot study, detecting 5/7 (71.4% [95% CI: 29.0% - 96.3%]) of clinically diagnosed untreated scabies patients). Greater sensitivity was observed in samples collected by FLOQ swabs compared to skin scrapings.

Conclusions/Significance

This newly developed qPCR assay, combined with the use of an alternative non-invasive swab sampling technique offers the possibility of enhanced diagnosis of scabies. Further studies will be required to better define the diagnostic performance of these tests.

As scabies control efforts continue to grow, scarcity of diagnostic options hinders success of elimination efforts in endemic areas. Efficiency in large-scale monitoring is further obstructed by invasive sample collection techniques, which are often uncomfortable for patients, and lack sensitivity. We have developed two PCR-based diagnostic assays targeting repetitive DNA elements. These were identified using new data on the S. scabiei genome. Targeting these elements by PCR improved the detection of scabies DNA. Enhanced sensitivity was demonstrated when tested against routine microscopy and a published PCR-based diagnostic assay. When combined with a non-invasive, effective FLOQ swab sampling method, the developed qPCR-based assays may provide a useful complementary tool for diagnosis of scabies, and its application will likely improve scabies control in target populations.

Crusted scabies; a 2-year prospective study from the Northern Territory of Australia

BACKGROUND

Scabies is listed as a neglected tropical disease by the World Health Organization. Crusted scabies affects vulnerable and immunosuppressed individuals and is highly contagious because of the enormous number of Sarcoptes scabiei mites present in the hyperkeratotic skin. Undiagnosed and untreated crusted scabies cases can result in outbreaks of scabies in residential facilities and can also undermine the success of scabies mass drug administration programs.

METHODS AND PRINCIPAL FINDINGS

Crusted scabies became a formally notifiable disease in the Northern Territory of Australia in 2016. We conducted a 2-year prospective study of crusted scabies cases notified between March 2016 and February 2018, with subsequent follow up for 22 months. Demographics, clinical and laboratory data, treatment and outcomes were analysed, with cases classified by severity of disease. Over the 2-year study period, 80 patients had 92 episodes of crusted scabies; 35 (38%) were Grade 1 crusted scabies, 36 (39%) Grade 2 and 21 (23%) Grade 3. Median age was 47 years, 47 (59%) were female, 76 (95%) Indigenous Australians and 57 (71%) from remote Indigenous communities. Half the patients were diabetic and 18 (23%) were on dialysis for end-stage kidney failure. Thirteen (16%) patients had no comorbidities, and these were more likely to have Grade 3 disease. Eosinophilia was present in 60% and high immunoglobulin E in 94%. Bacteremia occurred in 11 episodes resulting in one fatality with methicillin-susceptible Staphylococcus aureus bacteremia. Two other deaths occurred during admission and 10 others died subsequent to discharge consequent to comorbidities. Treatment generally followed the recommended guidelines, with 3, 5 or 7 doses of oral ivermectin depending on the documented grade of crusted scabies, together with daily alternating topical scabicides and topical keratolytic cream. While response to this therapy was usually excellent, there were 33 episodes of recurrent crusted scabies with the majority attributed to new infection subsequent to return to a scabies-endemic community.

CONCLUSIONS

Crusted scabies can be successfully treated with aggressive guideline-based therapy, but high mortality remains from underlying comorbidities. Reinfection on return to community is common while scabies remains endemic.

Digital dermoscopy: a complementary method in the diagnosis of scabies

Scabies is an ectoparasitosis caused by Sarcoptes scabiei var. hominis, characterized clinically by pruritic lesions in typical locations; the crusted form is a rare manifestation. The diagnosis is usually established based on the clinical picture, but dermoscopy can be an important complementary method, as it allows the observation of a brownish triangular structure with a hang-glider appearance. A case of crusted scabies is reported; the magnification of the images obtained by digital dermoscopy allowed the demonstration of a structure usually observed only with videodermoscopy.

Estimating the global burden of scabies: what else do we need?

Scabies is one of the most common disorders identified in any estimate of global skin disease prevalence. Furthermore, quantifying its impact on individuals and societies has been problematic. There has been a lack of clear case definitions and laboratory tests. There have been few epidemiological studies, particularly those focusing on low-income countries, variation in prevalence within high-income countries, or estimates of the effect of scabies on health beyond the skin, such as renal disease or mental wellbeing. Economic studies are also lacking. However, the new strategy of integrating surveillance for skin Neglected Tropical Diseases may well produce advancements on these issues, in addition to providing an overarching structure for health improvement and disease control.

Scabies: A comprehensive review and current perspectives

Human scabies is a contagious skin infestation caused by the parasitic mite Sarcoptes scabiei var. hominis. It is a common skin disease worldwide that occurs not only in the underprivileged sections of society but also in developed countries. In 2009, World Health Organization (WHO) recognized scabies as "neglected tropical disease (NTD)" or NTD thus emphasizing the need for community awareness and proper treatment strategies. This review attempts to summarize the varied clinical presentation of the disease and describes the advances in diagnosis and management including the ongoing search for novel agents to overcome the problems associated with conventional treatments. The literature research includes peer-reviewed articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) till February 2020 and reference lists of respective articles. Only articles published in English language were included.

Overdiagnosis of scabies and overprescribing of scabies treatment in a scabies-endemic region

OBJECTIVE

To assess the objective evidence upon which diagnosis of scabies and subsequent prescription of permethrin cream or oral ivermectin is based at a tertiary referral hospital in the Northern Territory.

DESIGN, SETTING AND PARTICIPANTS

A retrospective cohort study of inpatients who were prescribed permethrin or ivermectin between July and September 2017 at a single tertiary referral hospital. Eighty-eight inpatient admissions, belonging to 77 unique patients, were included. This list was generated with the hospital's electronic prescribing software.

MAIN OUTCOME MEASURES

Age, ethnicity, skin diagnosis on admission, which anti-scabies medications were prescribed, which concurrent medications were prescribed to treat a rash or pruritus, which differential or concurrent skin diagnoses were made, whether the dermatology department had seen the patient during their admission, and what evidence was documented as reason for diagnosis of scabies.

RESULTS

In the cases in which scabies treatment was prescribed, less than one quarter had positive skin scrapings for scabies, and few had documentation of burrows, and documentation of a contact history combined with clinical lesions. Most cases met none of these diagnostic criteria. Very few were reviewed by the dermatology department as an inpatient.

CONCLUSIONS

There were likely high rates of diagnostic uncertainty among the cases in which scabies treatment was prescribed. It is possible that anti-scabies medications are being prescribed empirically in this hospital.

Scabies: Application of the Novel Identify-Isolate-Inform Tool for Detection and Management

Scabies is a highly contagious, globally prevalent, parasitic skin infestation caused by Sarcoptes scabiei var. hominis, also known as the itch mite. There have been outbreaks not only in the developing world, but also in the developed world among refugees and asylum seekers. Once infested with scabies mites, symptomatic patients, as well as asymptomatic carriers, quickly spread the disease through direct skin-to-skin contact. Typically, symptoms of scabies are characterized by an erythematous, papular, pruritic rash associated with burrows. Treatment of scabies involves using topical or systemic scabicides and treating secondary bacterial infections, if present. Given the prevalence and contagiousness of scabies, measures to prevent its spread are essential. Through application of the novel Identify-Isolate-Inform (3I) Tool, emergency medical providers can readily identify risk factors for exposure and important symptoms of the disease, thus limiting its spread through prompt scabicide therapy; isolate the patient until after treatment; and inform local public health authorities and hospital infection prevention, when appropriate. Ultimately, these three actions can aid public health in controlling the transmission of scabies cases, thus ensuring the protection of the general public from this highly contagious skin infestation.

Crusted scabies in a pediatric renal transplant recipient on immunosuppressants

BACKGROUND

Crusted scabies (CS) is a rare, severe and highly contagious form of scabies, which has been reported in immunosuppressed patients. A high index of suspicion and awareness of CS is essential to treat this infestation.

CASE

A 13-year-old boy presented with pruritic hyperkeratotic squamous plaques located on both inner wrists, the web spaces of both his hands and his feet, and the genital area of 12 months duration. He was diagnosed with focal segmental glomerulosclerosis at the age of 5 and received a kidney transplant at the age of 9. He has been on a maintenance dose of prednisone (5 mg/d) and mycophenolate mofetil (250 mg/d) for the past 2 years. He had a contact history with a school friend with similar lesions. A skin punch biopsy demonstrated the presence of multiple mites in the stratum corneum confirming the diagnosis of CS. Ivermectin, the recommended drug of choice for crusted scabies, is not available in South Africa. The patient was commenced on topical benzoyl benzoate lotion but discontinued its use because of intolerable irritation. We subsequently prescribed the daily application of topical 5% sulfur in petrolatum to which his pruritus subsided significantly after 2 weeks with resolution of all skin lesions at the end of 8 weeks.

CONCLUSION

This case is the first documented report of CS in a pediatric renal transplant patient. Our management highlights that classic formularies of magistral drugs are still effective treatment options and can be used especially when standard therapies cannot be tolerated or when optimum treatments are not available.

SToP (See, Treat, Prevent) skin sores and scabies trial: study protocol for a cluster randomised, stepped-wedge trial for skin disease control in remote Western Australia

INTRODUCTION

Skin is important in Australian Aboriginal culture informing kinship and identity. In many remote Aboriginal communities, scabies and impetigo are very common. Untreated skin infections are painful, itchy and frequently go untreated due to under-recognition and lack of awareness of their potential serious complications. We hypothesise that the skin infection burden in remote Aboriginal communities can be reduced by implementing streamlined training and treatment pathways integrated with environmental health and health promotion activities, tested in the See, Treat, Prevent (SToP skin sores and scabies) trial.

METHODS AND ANALYSIS

SToP will evaluate a skin control programme using a stepped-wedge, cluster randomised trial design with three intervention components (the 'SToP activities'): (1) seeing skin infections (development of training resources implemented within a community dermatology model); (2) treating skin infections (employing the latest evidence for impetigo, and scabies treatment); and (3) preventing skin infections (embedded, culturally informed health promotion and environmental health activities). Four community clusters in the remote Kimberley region of Western Australia will participate. Following baseline data collection, two clusters will be randomly allocated to the SToP activities. At 12 months, the remaining two clusters will transition to the SToP activities. The primary outcome is the diagnosis of impetigo in children (5-9 years) at school-based surveillance. Secondary outcome measures include scabies diagnosis, other child health indicators, resistance to cotrimoxazole in circulating pathogenic bacteria, determining the economic burden of skin disease and evaluating the cost effectiveness of SToP activities.

ETHICS AND DISSEMINATION

This study protocol was approved by the health ethics review committees at the Child and Adolescent Health Service (Approval number RGS0000000584), the Western Australian Aboriginal Health Ethics Committee (Reference number: 819) and the University of Western Australia (Reference RA/4/20/4123). Study findings will be shared with community members, academic and medical communities via publications and presentations, and in reports to funders. Authorship for all publications based on this study will be determined in line with the Uniform Requirements for Manuscripts Submitted to Biomedical Journals published by the International Committee of Medical Journal Editors. Sharing results with organisations and communities who contributed to the study is paramount. The results of the SToP trial will be shared with participants in a suitable format, such as a single summary page provided to participants or presentations to communities, the Kimberly Aboriginal Health Planning Forum Research Subcommittee and other stakeholders as appropriate and as requested. Communication and dissemination will require ongoing consultation with Aboriginal communities to determine appropriate formats.

TRIAL REGISTRATION NUMBER

ACTRN12618000520235.

Ectoparasites: Scabies

Scabies is an ectoparasitic dermatosis caused by Sarcoptes scabiei var. hominis and is a public health issue in all countries regardless of socioeconomic status. In high-income countries, delays in diagnosis can lead to institutional outbreaks; in low- and middle-income countries, poor access to health care contributes to disease undertreatment and long-term systemic sequelae. With scabies now recognized as a neglected tropical disease by the World Health Organization, increased awareness and systematic efforts are addressing gaps in diagnosis and treatment that impede scabies control. This review summarizes the available data and provides an update on scabies epidemiology, clinical features, diagnosis, management, and public health considerations.

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.

Efficacy of mass drug administration with ivermectin for control of scabies and impetigo, with coadministration of azithromycin: a single-arm community intervention trial

BACKGROUND

In small community-based trials, mass drug administration of ivermectin has been shown to substantially decrease the prevalence of both scabies and secondary impetigo; however, their effect at large scale is untested. Additionally, combined mass administration of drugs for two or more neglected diseases has potential practical advantages, but efficacy of potential combinations should be confirmed.

METHODS

The azithromycin ivermectin mass drug administration (AIM) trial was a prospective, single-arm, before-and-after, community intervention study to assess the efficacy of mass drug administration of ivermectin for scabies and impetigo, with coadministration of azithromycin for trachoma. Mass drug administration was offered to the entire population of Choiseul Province, Solomon Islands, and of this population we randomly selected two sets of ten sentinel villages for monitoring, one at baseline and the other at 12 months. Participants were offered a single dose of 20 mg/kg azithromycin, using weight-based bands. Children weighing less than 12·5 kg received azithromycin oral suspension (20 mg/kg), and infants younger than 6 months received topical 1% tetracycline ointment. For ivermectin, participants were offered two doses of oral ivermectin 200 μg/kg 7-14 days apart using weight-based bands, or 5% permethrin cream 7-14 days apart if ivermectin was contraindicated. Our study had the primary outcomes of safety and feasibility of large-scale mass coadministration of oral ivermectin and azithromycin, which have been previously reported. We report here the prevalence of scabies and impetigo in residents of the ten baseline villages compared with those in the ten 12-month villages, as measured by examination of the skin, which was a secondary outcome of the trial. Further outcomes were comparison of the number of all-cause outpatient attendances at government clinics in Choiseul Province at various timepoints before and after mass drug administration. The trial was registered with the Australian and New Zealand Trials Registry (ACTRN12615001199505).

FINDINGS

During September, 2015, over 4 weeks, 26 188 people (99·3% of the estimated population of Choiseul [n=26 372] as determined at the 2009 census) were treated. At baseline, 1399 (84·2%) of 1662 people living in the first ten villages had their skin examined, of whom 261 (18·7%) had scabies and 347 (24·8%) had impetigo. At 12 months after mass drug administration, 1261 (77·6%) of 1625 people in the second set of ten villages had their skin examined, of whom 29 (2·3%) had scabies (relative reduction 88%, 95% CI 76·5-99·3) and 81 (6·4%) had impetigo (relative reduction 74%, 63·4-84·7). In the 3 months after mass drug administration, 10 614 attended outpatient clinics for any reason compared with 16 602 in the 3 months before administration (decrease of 36·1%, 95% CI 34·7-37·6), and during this period attendance for skin sores, boils, and abscesses decreased by 50·9% (95% CI 48·6-53·1).

INTERPRETATION

Ivermectin-based mass drug administration can be scaled to a population of over 25 000 with high efficacy and this level of efficacy can be achieved when mass drug administration for scabies is integrated with mass drug administration of azithromycin for trachoma. These findings will contribute to development of population-level control strategies. Further research is needed to assess durability and scalability of mass drug administration in larger, non-island populations, and to assess its effect on the severe bacterial complications of scabies.

FUNDING

International Trachoma Initiative, Murdoch Children's Research Institute, Scobie and Claire Mackinnon Trust, and the Wellcome Trust.

Treatment, prevention and public health management of impetigo, scabies, crusted scabies and fungal skin infections in endemic populations: a systematic review

We conducted a systematic review of the treatment, prevention and public health control of skin infections including impetigo, scabies, crusted scabies and tinea in resource‐limited settings where skin infections are endemic. The aim is to inform strategies, guidelines and research to improve skin health in populations that are inequitably affected by infections of the skin and the downstream consequences of these. The systematic review is reported according to the PRISMA statement. From 1759 titles identified, 81 full text studies were reviewed and key findings outlined for impetigo, scabies, crusted scabies and tinea. Improvements in primary care and public health management of skin infections will have broad and lasting impacts on overall quality of life including reductions in morbidity and mortality from sepsis, skeletal infections, kidney and heart disease.

A Review of Scabies: An Infestation More than Skin Deep

Human scabies, a common infestation, has a worldwide distribution with a variable impact and presentation depending on the clinical situation. In developed, high-income settings, health institution and residential home outbreaks challenge health and social care services. In resource-poor settings, it is the downstream sequelae of staphylococcal and streptococcal bacteraemia, induced by scratching, which have a significant impact on the long-term health of communities. Over the past decade scabies has been recognised as a “neglected tropical disease” (NTD) by the World Health Organisation, has an accepted practical system of global diagnostic criteria and is being adopted into integrated programmes of mass drug administration for NTDs in field settings. This review seeks to summarise the recent advances in the understanding of scabies and highlight the advocacy and research headlines with their implication for diagnosis and management of outbreaks and individuals. In addition, it will indicate the priorities and questions that remain.

Control Strategies for Scabies

Scabies is a neglected tropical disease of the skin, causing severe itching and stigmatizing skin lesions. Further, scabies leads to impetigo, severe bacterial infections, and post-infectious complications. Around 200 million people are affected, particularly among disadvantaged populations living in crowded conditions in tropical areas. After almost 50 years, research into scabies control has shown great promise, particularly in highly-endemic island settings, but these findings have not been widely adopted. Newer approaches, utilizing ivermectin-based mass drug administration, appear feasible and highly effective. Inclusion of scabies in the WHO portfolio of neglected tropical diseases in 2017 may facilitate renewed opportunities and momentum toward global control. However, further operational research is needed to develop evidence-based strategies for control in a range of settings, and monitor their impact. Several enabling factors are required for successful implementation, including availability of affordable drug supply. Integration with existing health programs may provide a cost-effective approach to control.

Scabies outbreaks in ten care homes for elderly people: a prospective study of clinical features, epidemiology, and treatment outcomes

Background

Scabies outbreaks in residential and nursing care homes for elderly people are common, subject to diagnostic delay, and hard to control. We studied clinical features, epidemiology, and outcomes of outbreaks in the UK between 2014 and 2015.

Methods

We did a prospective observational study in residential care homes for elderly people in southeast England that reported scabies outbreaks to Public Health England health protection teams. An outbreak was defined as two or more cases of scabies (in either residents or staff) at a single care home. All patients who provided informed consent were included; patients with dementia were included if a personal or nominated consultee (ie, a family member or nominated staff member) endorsed participation. Dermatology-trained physicians examined residents at initial clinical visits, which were followed by two mass treatments with topical scabicide as per local health protection team guidance. Follow-up clinical visits were held 6 weeks after initial visits. Scabies was diagnosed through pre-defined case definitions as definite, probable, or possible with dermatoscopy and microscopy as appropriate.

Findings

230 residents were examined in ten outbreaks between Jan 23, 2014, and April 13, 2015. Median age was 86·9 years (IQR 81·5–92·3), 174 (76%) were female, and 157 (68%) had dementia. 61 (27%) residents were diagnosed with definite, probable, or possible scabies, of whom three had crusted scabies. Physical signs differed substantially from classic presentations. 31 (51%) of the 61 people diagnosed with scabies were asymptomatic, and only 25 (41%) had burrows. Mites were visualised with dermatoscopy in seven (11%) patients, and further confirmed by microscopy in three (5%). 35 (57%) cases had signs of scabies only on areas of the body that would normally be covered. Dementia was the only risk factor for a scabies diagnosis that we identified (odds ratio 2·37 [95% CI 1·38–4·07]). At clinical follow-up, 50 people who were initially diagnosed with scabies were examined. No new cases of scabies were detected, but infestation persisted in ten people.

Interpretation

Clinical presentation of scabies in elderly residents of care homes differs from classic descriptions familiar to clinicians. This difference probably contributes to delayed recognition and suboptimal management in this vulnerable group. Dermatoscopy and microscopy were of little value. Health-care workers should be aware of the different presentation of scabies in elderly people, and should do thorough examinations, particularly in people with dementia.

Funding

Public Health England and British Skin Foundation.

Treatment of scabies using a tea tree oil-based gel formulation in Australian Aboriginal children: protocol for a randomised controlled trial

INTRODUCTION

In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their first birthday. This is more than six times the rate seen in the rest of the developed world. Scabies infestation is frequently complicated by bacterial infection, leading to the development of skin sores and other more serious consequences, such as septicaemia and chronic heart and kidney diseases. Tea tree oil (TTO) has been used as an antimicrobial agent for several decades with proven clinical efficacy. Preclinical investigations have demonstrated superior scabicidal properties of TTO compared with widely used scabicidal agents, such as permethrin 5% cream and ivermectin. However, current data are insufficient to warrant a broad recommendation for its use for the management of scabies because previous studies were small or limited to in vitro observations.

METHODS AND ANALYSIS

A pragmatic first trial will examine the clinical efficacy of a simple and low-cost TTO treatment against paediatric scabies and the prevention of associated secondary bacterial infections, with 1:1 randomisation of 200 participants (Aboriginal children, aged 5-16 years and living in remote Australia) into active control (permethrin 5% cream) and treatment (5% TTO gel) groups. The primary outcome for the study is clinical cure (complete resolution). Secondary outcome measures will include relief of symptoms, recurrence rate, adverse effects, adherence to treatment regimen and patient acceptability.

ETHICS AND DISSEMINATION

The project has received approvals from the University of Canberra Human Research Ethics Committee (HREC 16-133), Wurli-Wurlinjang Health Service Indigenous subcommittee and the Aboriginal Medical Services Alliance Northern Territory reference group. The results of this study will be published in core scientific publications, with extensive knowledge exchange activities with non-academic audiences throughout the duration of the project.

TRIAL REGISTRATION

ACTRN12617000902392; Pre-results.

The prevalence and association with health-related quality of life of tungiasis and scabies in schoolchildren in southern Ethiopia

Background

The prevalence of skin disease in low and middle income countries is high and communicable skin diseases are a significant public health problem. Tungiasis is an ectoparasite infestation caused by the flea Tunga penetrans, which has a widespread geographical distribution. Tungiasis causes painful skin lesions and may affect activities of daily living.

Objective

We wished to determine the prevalence and impact of tungiasis and scabies in schoolchildren in southern Ethiopia.

Methods

A cross-sectional study was performed in which students were examined by dermatologists and the skin disorders recorded. Individuals with pyogenic skin infections, scabies and tungiasis were also invited to complete the Children’s Dermatology Life Quality Index.

Results

There was a high burden of skin disease amongst this cohort with more than 40% having an ectodermal parasitic skin disease. The majority of these were due to tungiasis. Tungiasis was evident in more than a third of children and was associated with onychodystophy. There was a significant association between wearing “closed” footwear and a greater number of tungiasis lesions but not tungiasis per se. Dermatophyte infections, acne and plantar maceration secondary to occlusive footwear were also common.

Scabies and tungiasis appeared to have a significant negative effect on quality of life.

Conclusion

Tungiasis is highly prevalent in schoolchildren in the part of Ethiopia where the study was conducted and is associated with a deleterious effect on quality of life. The role of footwear in both preventing and possibly exacerbating cutaneous ailments in this setting requires further study.

Skin disorders are very common in all geographical locations and especially so in low and middle income countries. In these settings many of the commonest skin disorders are communicable.

Human ectoparasites such as lice and scabies mites live on the skin and Tunga penetrans fleas enter the skin to shed their eggs and complete their lifecycle. All of these ectoparasites cause significant morbidity particularly in poorer communities.

We have shown that the infestations of scabies and tungiasis were the commonest skin disorders in the Ethiopian schoolchildren examined in this study. These conditions are associated with a significant impact on the quality of life of these children as measured by the Children’s Dermatology Life Quality Index.

Footwear protects individuals from many conditions both infectious and non-infectious however in this cohort footwear was associated with maceration of the skin and this requires further investigation.

NORWEGIAN SCABIES IN AIDS PATIENT: A CASE REPORT

Scabies is a skin infection caused by Sarcoptes scabiei var. hominis. This disease may present severe clinical manifestations in immune-compromised patient, well-known as Norwegian scabies or crusted scabies.A 36-year old man with AIDS had chief complaint thick crust almost all over his body in this case. History of household member infected by scabies before was present. Clinical findings show hyperpigmented macules unsharply marginated, covered with thick scales and accompanied by papules, fissures, and erotion. T cell CD4 level was 12 cell/ µL. Scraping examination showed scabies infection and so did the histopathology examination. This patient was treated by topical Permethrin 5% combined with 2-4 ointment application in between permethrin usage. Before topical scabicide was given, thick crust was previously treated by topical urea 10% and wet dressing by normal saline. On day 14 after the patient first came there was lesion improvement.

[Severe crusted scabies: A "historic" case involving the death of a 52-year-old patient]

BACKGROUND

Crusted scabies, also known as Norwegian scabies, is a rare and extremely debilitating form of Sarcoptes scabiei var. hominis infestation that generally occurs in immunosuppressed patients. Herein, we report a "historic" and fatal case.

PATIENTS AND METHODS

A 52-year-old woman was admitted to the emergency department presenting crusted dermatitis together with extreme deterioration of her general condition. Her general practitioner had initiated dermo-corticosteroid therapy for suspected atopic dermatitis two months earlier, and she had been confined to bed for the previous 10 days. Her son presented pruritus that became worse at night. On examination the patient was moaning, dehydrated and confused and her entire skin was hyperkeratotic, with very thick, yellowish, cracked crusts covering 40 % of her body. Tests indicated severe water and electrolytic disorders as well as Staphylococcus aureus bacteremia. A tape test established the diagnosis of crusted scabies. The severity was grade III on the Davis clinical grading scale. The patient showed signs of multi-organ failure and was transferred to intensive care, but she died during the night.

DISCUSSION

This case is remarkable for its historic severity. In France, scabies infestation is a re-emerging disease and has been a public health priority since 2012. The rare hyperkeratotic form is not fully understood and frequently diagnosed late, in some cases with a fatal outcome.

Therapeutic Potential of Tea Tree Oil for Scabies

Globally, scabies affects more than 130 million people at any time. In the developed world, outbreaks in health institutions and vulnerable communities result in a significant economic burden. A review of the literature demonstrates the emergence of resistance toward classical scabicidal treatments and the lack of effectiveness of currently available scabicides in reducing the inflammatory skin reactions and pyodermal progression that occurs in predisposed patient cohorts. Tea tree oil (TTO) has demonstrated promising acaricidal effects against scabies mites in vitro and has also been successfully used as an adjuvant topical medication for the treatment of crusted scabies, including cases that did not respond to standard treatments. Emerging acaricide resistance threatens the future usefulness of currently used gold standard treatments (oral ivermectin and topical permethrin) for scabies. The imminent development of new chemical entities is doubtful. The cumulative acaricidal, antibacterial, antipruritic, anti-inflammatory, and wound healing effects of TTO may have the potential to successfully reduce the burden of scabies infection and the associated bacterial complications. This review summarizes current knowledge on the use of TTO for the treatment of scabies. On the strength of existing data for TTO, larger scale, randomized controlled clinical trials are warranted.

Use of a clinical tool for screening and diagnosis of cutaneous leishmaniasis in Sri Lanka

Cutaneous leishmaniasis (CL) was first detected in Sri Lanka in 1992.Local disease is caused by a genetically different variant of Leishmania donovani. Early case detection and management is the mainstay of L. donovani control. High degree of clinical suspicion is critical but a clinical diagnostic tool is not available for leishmaniasis. Current study described, for the first time, a two-staged clinical algorhythm that facilitates screening of CL in Sri Lanka by primary health care worker in stage 1 and management by medical professional in stage 2.Selected clinical markers of 400 patients suspected of CL were analysed retrospectively with laboratory confirmation of leishmaniasis. Ten clinical markers predicted CL with a over 90% accuracy. Subsets of markers showed high levels of sensitivities (60-97.2%) and/or significant association with positive laboratory results as compared to negative lesions [typical onset (acne-form, painless non-itchy), (P = 0.026), size up to 2 cm (P = 0.046), well-defined edges (P = 0.002), regular edges (P = 0.018), rounded shape (P = 0.030), and lesions at 5-8 months (P = 0.052)]. Five of them (typical onset, number up to 2, small size, rounded edges, and rounded shape) also had > 70% sensitivity levels as compared to laboratory findings. Typical onset had the highest sensitivity of 97% and a PPV of 72%. Lesions at 5-8 months duration having defined edges (P =  0.013, specificity 89.7%, PPV 83.1) or having regular edges (P = 0.006, specificity 86.2%, PPV 82.4%) were also predictive of CL. Most of early laboratory-confirmed ( < 12 months) lesions remained  < 3 cm (sensitivity > 67%, PPV > 70%) and had defined edges (sensitivity of 52-71%, specificity 46.7-68.8%), (PPV 75.1-86%). Four clinical markers served as good diagnostic markers in both early ( ≤ 4) and late (>12 months) lesions, viz. typical onset (91.3-98.4%), presence of ≤ 2 lesions (sensitivity 82.6-94.7%), size ≤ 2 cm (66.9-73.7%), and regular edges (68.6-76.3%). Reliability of clinical markers generally declined in chronic lesions. However, small lesions of over 12 months were highly indicative of CL (sensitivity of 66%, specificity 66.7%). None of the single/combination markers, however, were 100% sensitive or specific, highlighting the undeniable usefulness of laboratory confirmation, in diagnosis. Decision-making algorithm used 10 basic clinical features for screening and seven specific clinical markers for clinical handling and referral for investigations.

Prospective study in a porcine model of sarcoptes scabiei indicates the association of Th2 and Th17 pathways with the clinical severity of scabies

Background

Understanding of scabies immunopathology has been hampered by the inability to undertake longitudinal studies in humans. Pigs are a useful animal model for scabies, and show clinical and immunologic changes similar to those in humans. Crusted scabies can be readily established in pigs by treatment with the glucocorticoid dexamethasone (Dex).

Methodology/ Principal Findings

Prospective study of 24 pigs in four groups: a) Scabies+/Dex+, b) Scabies+/Dex-, c) Scabies-/Dex+ and d) Scabies-/Dex-. Clinical symptoms were monitored. Histological profiling and transcriptional analysis of skin biopsies was undertaken to compare changes in cell infiltrates and representative cytokines. A range of clinical responses to Sarcoptes scabiei were observed in Dex treated and non-immunosuppressed pigs. An association was confirmed between disease severity and transcription of the Th2 cytokines IL-4 and IL-13, and up-regulation of the Th17 cytokines IL-17 and IL-23 in pigs with crusted scabies. Immunohistochemistry revealed marked infiltration of lymphocytes and mast cells, and strong staining for IL-17.

Conclusions/ Significance

While an allergic Th2 type response to scabies has been previously described, these results suggest that IL-17 related pathways may also contribute to immunopathology of crusted scabies. This may lead to new strategies to protect vulnerable subjects from contracting recurrent crusted scabies.

Scabies is a neglected tropical skin disease caused by the tiny parasitic mite Sarcoptes scabiei. Scabies is common in developing countries, and scabies outbreaks also occur in institutional settings worldwide. Scabies often underlies secondary bacterial skin infection and resulting complications, and is thus associated with considerable morbidity. Crusted scabies is a an extremely severe and debilitating clinical form of the disease, but host immune responses leading to the development of crusted or ordinary scabies are poorly understood. This is largely due to limited access to clinical samples, and the difficulty in monitoring the progression of infestation in human patients. We have overcome this challenge by using a pig model of scabies infestation, since pigs and humans with scabies display clinical and immunological similarities. In this study, we undertook longitudinal analysis of clinical, histological and molecular immunological changes in pigs experimentally infected with scabies. We confirmed that disease severity was associated with a pronounced allergic, Th2 immune response, as previously reported. In a novel finding, we showed that the Th17 associated cytokines interleukin-17 and interleukin-23 were also associated with the development of crusted scabies. This may lead to new immunotherapeutic strategies to protect vulnerable subjects from contracting recurrent crusted scabies.

Parasitic mites of medical and veterinary importance--is there a common research agenda?

There are an estimated 0.5-1 million mite species on earth. Among the many mites that are known to affect humans and animals, only a subset are parasitic but these can cause significant disease. We aim here to provide an overview of the most recent work in this field in order to identify common biological features of these parasites and to inform common strategies for future research. There is a critical need for diagnostic tools to allow for better surveillance and for drugs tailored specifically to the respective parasites. Multi-'omics' approaches represent a logical and timely strategy to identify the appropriate mite molecules. Recent advances in sequencing technology enable us to generate de novo genome sequence data, even from limited DNA resources. Consequently, the field of mite genomics has recently emerged and will now rapidly expand, which is a particular advantage for parasitic mites that cannot be cultured in vitro. Investigations of the microbiota associated with mites will elucidate the link between parasites and pathogens, and define the role of the mite in transmission and pathogenesis. The databases generated will provide the crucial knowledge essential to design novel diagnostic tools, control measures, prophylaxes, drugs and immunotherapies against the mites and associated secondary infections.

Crusted scabies in remote Australia, a new way forward: lessons and outcomes from the East Arnhem Scabies Control Program

Crusted scabies is a highly infectious, debilitating and disfiguring disease, and remote Aboriginal communities of northern Australia have the highest reported rates of the condition in the world. We draw on monitoring data of the East Arnhem Scabies Control Program to discuss outcomes and lessons learnt through managing the condition in remote communities. Using active case finding, we identified seven patients with crusted scabies in three communities and found most had not presented to health services despite active disease. We compared presentations and hospitalisations for a cumulative total of 99 months during a novel preventive program with 99 months immediately before the program for the seven cases and seven sentinel household contacts. Our preventive long-term case management approach was associated with a significant 44% reduction in episodes of recurrent crusted scabies (from 36 to 20; P = 0.025) in the seven cases, and a non-significant 80% reduction in days spent in hospital (from 173 to 35; P = 0.09). It was also associated with a significant 75% reduction in scabies-related presentations (from 28 to 7; P = 0.017) for the seven sentinel household contacts. We recommend active surveillance and wider adoption of this preventive case management approach, with ongoing evaluation to refine protocols and improve efficiency. Contacts of children presenting with recurrent scabies should be examined to exclude crusted scabies. In households where crusted scabies is present, a diagnosis of parental neglect due to recurrent scabies and weight loss in children should be made with extreme caution. Improved coordination of care by health services, and research and development of new therapies including immunotherapies for crusted scabies, must be a priority.