Permethrin and ivermectin for scabies

Clinical practice guidelines for the diagnosis and treatment of scabies

Scabies, caused by the Sarcoptes scabiei var hominis mite burrowing into the skin, is a highly contagious disease characterized by intense nocturnal itching. Its global impact is considerable, affecting more than 200 million individuals annually and posing significant challenges to healthcare systems worldwide. Transmission occurs primarily through direct skin-to-skin contact, contributing to its widespread prevalence and emergence as a substantial public health concern affecting large populations. This review presents consensus-based clinical practice guidelines for diagnosing and managing scabies, developed through the fuzzy Delphi method by dermatology, parasitology, pediatrics, pharmacology, and public health experts. The presence of burrows containing adult female mites, their eggs, and excreta is the diagnostic hallmark of scabies. Definitive diagnosis typically involves direct microscopic examination of skin scrapings obtained from these burrows, although dermoscopy has become a diagnostic tool in clinical practice. Treatment modalities encompass topical agents, such as permethrin, balsam of Peru, precipitated sulfur, and benzyl benzoate. In cases where topical therapy proves inadequate or in instances of crusted scabies, oral ivermectin is recommended as a systemic treatment option. This comprehensive approach addresses the diagnostic and therapeutic challenges associated with scabies, optimizing patient care, and management outcomes.

Novel Patient-Friendly Orodispersible Formulation of Ivermectin is Associated With Enhanced Palatability, Controlled Absorption, and Less Variability: High Potential for Pediatric Use

Ivermectin has been used since the 1980s as an anthelmintic and antiectoparasite agent worldwide. Currently, the only available oral formulation is tablets designed for adult patients. A patient-friendly orodispersible tablet formulation designed for pediatric use (CHILD-IVITAB) has been developed and is entering early phase clinical trials. To inform the pediatric program of CHILD-IVITAB, 16 healthy adults were enrolled in a phase I, single-center, open-label, randomized, 2-period, crossover, single-dose trial which aimed to compare palatability, tolerability, and bioavailability and pharmacokinetics of CHILD-IVITAB and their variability against the marketed ivermectin tablets (STROMECTOL) at a single dose of 12 mg in a fasting state. Palatability with CHILD-IVITAB was considerably enhanced as compared to STROMECTOL. Both ivermectin formulations were well tolerated and safe. Relative bioavailability of CHILD-IVITAB compared to STROMECTOL was estimated as the ratios of geometric means for Cmax, AUC 0-∞, and AUC0-last, which were 1.52 [90% CI: 1.13-2.04], 1.27 [0.99-1.62], and 1.29 [1.00-1.66], respectively. Maximum drug concentrations occurred earlier with the CHILD-IVITAB formulation, with a median Tmax at 3.0 h [range 2.0-4.0 h] versus 4.0 h [range 2.0-5.0 h] with STROMECTOL (P = .004). With CHILD-IVITAB, variability in exposure was cut in half (coefficient of variation: 37% vs 70%) compared to STROMECTOL. Consistent with a more controlled absorption process, CHILD-IVITAB was associated with reduced variability in drug exposure as compared to STROMECTOL. Together with a favorable palatability and tolerability profile, these findings motivate for further clinical studies to evaluate benefits of such a patient-friendly ODT formulation in pediatric patients with a parasitic disease, including infants and young children <15 kg.

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.

One versus two doses of ivermectin-based mass drug administration for the control of scabies: A cluster randomised non-inferiority trial

BACKGROUND

Mass drug administration (MDA) based on two doses of ivermectin, one week apart, substantially reduces prevalence of both scabies and impetigo. The Regimens of Ivermectin for Scabies Elimination (RISE) trial assessed whether one-dose ivermectin-based MDA would be as effective.

METHODS

RISE was a cluster-randomised trial in Solomon Islands. We assigned 20 villages in a 1:1 ratio to one- or two-dose ivermectin-based MDA. We planned to test whether the impact of one dose on scabies prevalence at 12 and 24 months was non-inferior to two, at a 5% non-inferiority margin.

RESULTS

We deferred endpoint assessment to 21 months due to COVID-19. We enrolled 5239 participants in 20 villages at baseline and 3369 at 21 months from an estimated population of 5500. At baseline scabies prevalence was similar in the two arms (one-dose 17·2%; two-dose 13·2%). At 21 months, there was no reduction in scabies prevalence (one-dose 18·7%; two-dose 13·4%), and the confidence interval around the difference included values substantially greater than 5%. There was however a reduction in prevalence among those who had been present at the baseline assessment (one-dose 15·9%; two-dose 10·8%). Additionally, we found a reduction in both scabies severity and impetigo prevalence in both arms, to a similar degree.

CONCLUSIONS

There was no indication of an overall decline in scabies prevalence in either arm. The reduction in scabies prevalence in those present at baseline suggests that the unexpectedly high influx of people into the trial villages, likely related to the COVID-19 pandemic, may have compromised the effectiveness of the MDA. Despite the lack of effect there are important lessons to be learnt from this trial about conducting MDA for scabies in high prevalence settings.

TRIAL REGISTRATION

Registered with Australian New Zealand Clinical Trials Registry ACTRN12618001086257.

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.

[Translated article] Epidemic Scabies: New Treatment Challenges in an Ancient Disease

Scabies which is among the most prevalent diseases worldwide, is becoming more frequent in Spain. The problems of this epidemic can be explained by several factors: improper application or prescription of treatments, resistance or reduced sensitivity to topical treatments, and poor understanding of the parasite and contagion. We require a new evidence-based approach to therapy that takes these problems into consideration. If symptoms persist after proper treatment, it is important to identify the reason for failure and standardize our approach. In refractory cases, the prescriber should prioritize oral medication, indicate a higher dose, combine treatments, or evaluate the use of off-label treatments in certain populations. The availability of new medications, such as spinosad or, especially, moxidectin, offer hope for bringing this disease under control.

Epidemic Scabies: New Treatment Challenges in an Ancient Disease

Scabies, which is among the most prevalent diseases worldwide, is becoming more frequent in Spain. The problems of this epidemic can be explained by several factors: improper application or prescription of treatments, resistance or reduced sensitivity to topical treatments, and poor understanding of the parasite and contagion. We require a new evidence-based approach to therapy that takes these problems into consideration. If symptoms persist after proper treatment, it is important to identify the reason for failure and standardize our approach. In refractory cases, the prescriber should prioritize oral medication, indicate a higher dose, combine treatments, or evaluate the use of off-label treatments in certain populations. The availability of new medications -such as spinosad or, especially, moxidectin- offer hope for bringing this disease under control.

Comparison of topical benzyl benzoate vs. oral ivermectin in treating scabies: A randomized study

BACKGROUND

Scabies is an itchy, parasitic infection of the skin. Recent reports indicate there is a decreasing efficacy of the standard treatment of choice, topical 5% permethrin cream.

OBJECTIVE

To evaluate the comparative efficacy, safety and tolerability of topical benzyl benzoate (BB) with oral ivermectin in the treatment of scabies.

METHODS

Patients with dermoscopy-verified scabies visiting the dermatologic outpatient clinic were assessed for enrolment in the study. In total, 224 patients were enrolled and sequentially randomized into two equally sized groups. Group A received topical 25% or 10% BB for the daily use over a period of three consecutive days, group B received oral ivermectin (200 μg/kg body weight) twice, 1 week apart. Treatment outcome was evaluated by dermoscopy at a 3-week follow-up visit.

RESULTS

Treatment resulted in a cure rate of 87% in group A and 86% in group B. After initial therapy failure in group A, six out of eight patients showed treatment response upon repeated application of BB, five of five when retreated with ivermectin and two of two with BB plus ivermectin, respectively. In group B, successful retreatment was observed in three out of three patients with ivermectin, two of two patients with BB and 11 of 11 patients with the combination of BB plus ivermectin, respectively. Tolerability and safety profile of oral ivermectin was excellent, while BB produced short burning sensations in 14%.

CONCLUSION

Topical BB and oral ivermectin have shown comparable good therapeutic efficacy. Therefore, both agents constitute an adequate first-line therapy in the treatment of scabies. A combination of both agents may be considered in recalcitrant and extensively infested cases, additionally to crusted scabies.

Permethrin inhibits tube formation and viability of endothelial cells

BACKGROUND

Exposure to environmental chemicals has been linked with endothelial dysfunction, which is a leading cause of human diseases, including atherosclerosis. Permethrin is a frequently used synthetic pyrethroid insecticide for which longer exposure may cause toxicity in several types of tissues and the development of metabolic diseases, including atherosclerosis, obesity and diabetes. The present study was designed to evaluate the potential adverse effect of permethrin on the function and activity of human endothelial cells.

RESULTS

Permethrin was found to repress migration and tube formation by human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner, as well as to significantly repress their viability after 24 and 48 h of treatment. Furthermore, increased reactive oxygen species (ROS) production was observed in cells treated with permethrin, and the permethrin-induced repression of cell viability was ROS-dependent. Permethrin did not influence apoptosis, necrosis or mitochondrial membrane potential in HUVECs.

CONCLUSION

The results of the present study suggest that permethrin represses angiogenesis and viability through ROS-dependent and cell growth-, apoptosis- and necrosis-independent means. © 2022 Society of Chemical Industry.

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.

Comparison of Permethrin-Based Treatment Strategies against Scabies in Infants and Young Children

OBJECTIVE

To optimize the permethrin-based therapies for scabies infestations in infants and young children, the efficacies of 3 different regimens were evaluated.

STUDY DESIGN

The retrospective analysis encompassed 85 infants and children aged <4 years with scabies. The children had received either topical permethrin 5% on the entire body on days 1/8, on days 1/8/15, on days 1/8/15 plus interim applications restricted to hands and feet on days 2/3/4//9/10/11, or alternative treatments.

RESULTS

The intensified regimen, consisting of full-body permethrin applied on days 1/8/15 and hands/feet on days 2/3/4//9/10/11, resulted in cure of scabies in 73.5% of the cases. The cure rates were significantly greater compared with full-body permethrin given on days 1/8, which led to eradication in 44%, and were greater compared with the clearance in children who had received full-body permethrin on days 1/8/15 (53.8%) or alternative treatments (60%). For patients in whom permethrin had previously been applied, the intensified regimen resulted in eradication of scabies in 71.4% of the cases, compared with 30% and 55.6% after full-body permethrin on days 1/8 and 1/8/15, respectively.

CONCLUSIONS

The intensified regimen of full-body permethrin plus interim applications on hands/feet, which aims at reducing the number of mites present on the frequently heavily infested palmoplantar sites in addition to the standard entire body application, appears efficacious in curing scabies in young children.

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.

Drug dose and animal welfare: important considerations in the treatment of wildlife

A recent publication in Parasitology Research by (Old et al. Parasitol Res 120:1077-1090, 2021) raises the topical and often controversial issue of the treatment of wildlife by personnel with little or no formal scientific training (e.g. wildlife carers). In a valuable contribution to the subject, Old and colleagues document a wide range of topical (pour-on) application doses and frequencies of moxidectin (Cydectin®) administered in situ to bare-nosed wombats (Vombatus ursinus) by members of the wildlife carer/treater community in southeast Australia to treat sarcoptic mange disease. This treatment occurred under minor use permits issued by the Australian Pesticides and Veterinary Management Authority (APVMA). These permits do not require veterinary supervision, although carers are registered and are expected to comply with the guidelines of this permit.The prevalence and severity of sarcoptic mange in wildlife is influenced by a variety of factors including mite biology, environmental conditions, population density, animal behaviour and immune susceptibility (Browne et al. Bioscience, 2021). In bare-nosed wombats, combinations of these elements play a substantial role in making the treatment of an already difficult disease more complex. (Moroni et al. Parasit Vectors 13:471, 2020) comment that any pharmacological treatment of free-ranging wildlife must consider these factors when assessing their feasibility and implications, especially in the context of emerging drug resistance and potential long-term ecological impacts. As individuals with significant interest in sarcoptic mange and representing a range of professional research and veterinary expertise, we see value in providing expert commentary on this issue.

Mass drug administration for the control of scabies: a systematic review and meta-analysis

BACKGROUND

Scabies is a neglected tropical disease of the skin that can lead to impetigo, serious secondary bacterial infections and immune-mediated diseases. Mass drug administration (MDA) has been reported in several studies to reduce the prevalence of scabies and impetigo. We aimed to assess the efficacy of MDA for scabies on scabies and impetigo.

METHODS

We conducted a systematic review and meta-analysis of reports on the impact of MDA on scabies and impetigo. We included randomised control trials and observational evaluations reported from January 1970 to April 2021 and involving human participants. We searched PubMed, Ovid Medline, Embase and Cochrane. We considered MDA as treatment intended for the whole population, regardless of individual infection status or symptoms. The main outcome assessed was the change in scabies and impetigo prevalence following MDA. This review is registered with PROSPERO (CRD42020169839).

RESULTS

We identified 1110 records, of which 11 met inclusion criteria for the review and 9 were deemed suitable for meta-analysis for scabies and four for impetigo. Most studies were in small populations. There was a high degree of heterogeneity between studies (I 2 value 96·19%). The overall relative reduction of the impact of MDA on scabies prevalence was 79%. The effect size was comparable for MDA based on ivermectin and permethrin. MDA for scabies also led to a reduction in impetigo prevalence with a relative reduction of 66%.

CONCLUSIONS

MDA for scabies is highly effective in reducing the prevalence of scabies and impetigo. Further research is needed to determine the durability of impact, and the effectiveness of MDA regimens in larger populations.

Community control strategies for scabies: A cluster randomised noninferiority trial

BACKGROUND

Scabies is a neglected tropical disease hyperendemic to many low- and middle-income countries. Scabies can be successfully controlled using mass drug administration (MDA) using 2 doses of ivermectin-based treatment. If effective, a strategy of 1-dose ivermectin-based MDA would have substantial advantages for implementing MDA for scabies at large scale.

METHODS AND FINDINGS

We did a cluster randomised, noninferiority, open-label, 3-group unblinded study comparing the effectiveness of control strategies on community prevalence of scabies at 12 months. All residents from 35 villages on 2 Fijian islands were eligible to participate. Villages were randomised 1:1:1 to 2-dose ivermectin-based MDA (IVM-2), 1-dose ivermectin-based MDA (IVM-1), or screen and treat with topical permethrin 5% for individuals with scabies and their household contacts (SAT). All groups also received diethylcarbamazine and albendazole for lymphatic filariasis control. For IVM-2 and IVM-1, oral ivermectin was dosed at 200 μg/kg and when contraindicated substituted with permethrin. We designated a noninferiority margin of 5%. We enrolled 3,812 participants at baseline (July to November 2017) from the 35 villages with median village size of 108 (range 18 to 298). Age and sex of participants were representative of the population with 51.6% male and median age of 25 years (interquartile range 10 to 47). We enrolled 3,898 at 12 months (July to November 2018). At baseline, scabies prevalence was similar in all groups: IVM-2: 11.7% (95% confidence interval (CI) 8.5 to 16.0); IVM-1: 15.2% (95% CI 9.4 to 23.8); SAT: 13.6% (95% CI 7.9 to 22.4). At 12 months, scabies decreased substantially in all groups: IVM-2: 1.3% (95% CI 0.6 to 2.5); IVM-1: 2.7% (95% CI 1.1 to 6.5); SAT: 1.1% (95% CI 0.6 to 2.0). The risk difference in scabies prevalence at 12 months between the IVM-1 and IVM-2 groups was 1.2% (95% CI -0.2 to 2.7, p = 0.10). Limitations of the study included the method of scabies diagnosis by nonexperts, a lower baseline prevalence than anticipated, and the addition of diethylcarbamazine and albendazole to scabies treatment.

CONCLUSIONS

All 3 strategies substantially reduced prevalence. One-dose was noninferior to 2-dose ivermectin-based MDA, as was a screen and treat approach, for community control of scabies. Further trials comparing these approaches in varied settings are warranted to inform global scabies control strategies.

TRIAL REGISTRATION

Clinitrials.gov NCT03177993 and ANZCTR N12617000738325.

[Epidemiology of scabies in Germany: multisource analysis of primary and secondary data]

BACKGROUND

Scabies is one of the most common and, in terms of burden of disease, one of the most significant skin diseases worldwide. In Germany, an increase in cases is currently being discussed, for which reliable data have been lacking until now.

OBJECTIVES

The goal is to clarify the prevalence and treatment of scabies in Germany.

MATERIALS AND METHODS

Multisource analyses of treatment data from a nationwide statutory health insurance company, the Federal Statistical Office and company skin screenings.

RESULTS

In Germany, the number of cases of scabies has been rising since 2009 and especially since 2014. In the outpatient setting, there was an increase of 52.8% to around 128,000 treatment cases between 2010 and 2015. Currently, more than 11,000 inpatient cases are documented annually in Germany with scabies as the main diagnosis (ICD-10 B86). The increase between 2010 and 2016 was about 306%. The main outpatient specialist groups providing care are dermatologists and general practitioners, while in the inpatient sector treatment is provided by departments of dermatology, paediatrics and internal medicine.

CONCLUSION

Due to the aforementioned development of prevalence and incidence, the need for care will remain at a high level in the future, which suggests an increased need for education and early detection.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Sarcoptes Infestation. What Is Already Known, and What Is New about Scabies at the Beginning of the Third Decade of the 21st Century?

Currently, there are three known subtypes of scabies: ordinary, crusted, and bullous. The worldwide prevalence of scabies remains high in the 21st century. To decrease the social, economic, and psychological impact on the enormous population infected, a lot of important work has been completed over the last 20 years concerning the management of scabies. For example, a standardization of guidelines for the treatment of scabies has been completed and programs have been designed for the prevention and treatment in endemic populations, called mass drug administrations. Unfortunately, these only apply to the ordinary form of scabies. Moreover, resistance to the drugs currently used in treatment is growing, which imposes the need to search for new treatments. For this purpose, new acaricides are being developed to enhance the therapeutic options for the patients' benefit and effectively treat this disease. There is also the necessity for prevention before the development of scabies. An effective vaccine has the potential to protect people before this disease, especially in endemic areas. Unfortunately, there are no such vaccines against Sarcoptes yet.

A narrative review of the roles of topical permethrin and oral ivermectin in the management of infantile scabies

As standard treatments are not licensed for use in the infantile population, the treatment of scabies in this age group can be challenging. We review the relevant evidence to determine the roles of topical permethrin and oral ivermectin in the management of infantile scabies. Demographic and clinical data were collected from relevant English articles published from January 2000 to December 2020. Complete resolution was observed in 100% of infants younger than two months treated with permethrin, and 87.6% of infants aged 12 months or less and/or children weighing under 15 kg treated with ivermectin. Adverse effects from permethrin use were limited to local eczematous reactions. Adverse effects from ivermectin use included mildly elevated creatine kinase levels, eczema flare-ups, diarrhoea, vomiting, irritability, pruritus and pustular skin reactions. Overall, both permethrin and ivermectin appear to have an acceptable safety profile in infants. Permethrin is highly effective as a first-line therapy for scabies in infants younger than two months. Ivermectin use is recommended when authorised topical treatment has failed, in crusted scabies, in cases where compliance with topical agents may be problematic, and in infants with severely inflamed or broken skin where prescription of topical therapies would likely cause cutaneous and systemic toxicity. Additional high-quality studies are needed to guide best practice in the management of infantile scabies.

A facility and community-based assessment of scabies in rural Malawi

BACKGROUND

Scabies is a neglected tropical disease of the skin, causing severe itching, stigmatizing skin lesions and systemic complications. Since 2015, the DerMalawi project provide an integrated skin diseases clinics and Tele-dermatology care in Malawi. Clinic based data suggested a progressive increase in scabies cases observed. To better identify and treat individuals with scabies in the region, we shifted from a clinic-based model to a community based outreach programme.

METHODOLOGY/PRINCIPAL FINDINGS

From May 2015, DerMalawi project provide integrated skin diseases and Tele-dermatological care in the Nkhotakota and Salima health districts in Malawi. Demographic and clinical data of all patients personally attended are recorded. Due to a progressive increase in the number of cases of scabies the project shifted to a community-based outreach programme. For the community outreach activities, we conducted three visits between 2018 to 2019 and undertook screening in schools and villages of Alinafe Hospital catchment area. Treatment was offered for all the cases and school or household contacts. Scabies increased from 2.9% to 39.2% of all cases seen by the DerMalawi project at clinics between 2015 to 2018. During the community-based activities approximately 50% of the population was assessed in each of three visits. The prevalence of scabies was similar in the first two rounds, 15.4% (2392) at the first visit and 17.2% at the second visit. The prevalence of scabies appeared to be lower (2.4%) at the third visit. The prevalence of impetigo appeared unchanged and was 6.7% at the first visit and 5.2% at the final visit.

CONCLUSIONS/SIGNIFICANCE

Prevalence of scabies in our setting was very high suggesting that scabies is a major public health problem in parts of Malawi. Further work is required to more accurately assess the burden of disease and develop appropriate public health strategies for its control.

Scabies itch: an update on neuroimmune interactions and novel targets

Frequently described as 'the worst itch' one can ever experience scabies itch is the hallmark of Sarcoptes scabiei mite infestation. Notably, the itchiness often persists for weeks despite scabicides therapy. The mechanism of scabies itch is not yet fully understood, and effective treatment modalities are still missing which can severely affect the quality of life. The aim of this review is to provide an overview of the scope of itch in scabies and highlight candidate mechanisms underlying this itch. We herein discuss scabies itch, with a focus on the nature, candidate underlying mechanisms and treatment options. We also synthesize this information with current understanding of the mechanisms contributing to non-histaminergic itch in other conditions. Itch is a major problem in scabies and can lead to grave consequences. We provide the latest insights on host-mite interaction, secondary microbial infection and neural sensitization with special emphasis on keratinocytes and mast cells to better understand the mechanism of itch in scabies. Also, the most relevant current modalities remaining under investigation that possess promising perspectives for scabies itch (i.e. protease-activated receptor-2 (PAR-2) inhibitor, Mas-related G protein-coupled receptor X2 (MRGPRX2) antagonist) are discussed. Greater understanding of these diverse mechanisms may provide a rational basis for the development of improved and targeted approaches to control itch in individuals with scabies.

Paediatrics: how to manage scabies

This narrative review addresses scabies, a highly contagious, pruritic infestation of the skin caused by the mite Sarcoptes scabiei var hominis. Scabies is a common disorder that has a prevalence worldwide estimated to be between 200 and 300 million cases per year. Infestation is of greatest concern in children, the elderly, immunocompromised people and resource-poor endemic populations at risk of chronic complications. A diagnosis of scabies involves a clinical suspicion, a detailed targeted history, clinical examination and contact tracing. Dermoscopy and microscopy, where available, is confirmatory. Due to its infectivity and transmissibility, the management for scabies requires a multimodal approach: topical antiscabetic agents are the first line for most cases of childhood classic scabies and their contacts, which must also be identified and treated to prevent treatment failure and reacquisition. Environmental strategies to control fomite-related reinfestation are also recommended. Oral ivermectin, where available, is reserved for use in high-risk cases in children or in mass drug administration programmes in endemic communities. The prevention of downstream complications of scabies includes surveillance, early identification and prompt treatment for secondary bacterial infections, often superficial but can be serious and invasive with associated chronic morbidity and mortality. Post-scabetic itch and psychosocial stigma are typical sequelae of the scabies mite infestation. The early identification of patients with scabies and treatment of their contacts reduces community transmission. Although time consuming and labour intensive for caregivers, the implementation of appropriate treatment strategies usually results in prompt cure for the child and their contacts. Here, we provide a summary of treatments and recommendations for the management of paediatric scabies.

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.

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.

Host-Parasite Interaction in Sarcoptes scabiei Infestation in Porcine Model with a Preliminary Note on Its Genetic Lineage from India

Simple Summary

Scabies or mange caused by Sarcoptess cabiei is the latest addition of WHO’s list oftropical neglected diseases. It causes severe itching to the host. It has a wide host range including humans, farm animals, companion animals, and wild animals. It is anemerging/re-emerging disease with high prevalence in underdeveloped and developing countries. The disease has zoonotic importance and is of significant public health concern as cross-transmission or species jumping is very common. To date, fifteen Sarcoptes varieties have been reported as per host origin. Differential diagnosis at variety level is very crucial for epidemiological study and scratching future eradication program of the disease. As morphotaxonomy fails to differentiate varieties, use of molecular markers is crucial. Moreover, it is very important to understand the host-parasite interaction at the systemic level for a better understanding on the pathogenicity of the disease. Here, we report the genetic characterization of S. scabiei from India and host-parasite interaction in a porcine model.

Abstract

The burrowing mite Sarcoptes scabiei causes scabies in humans or mange in animals. It infests a wide range of mammalian species including livestock, companion animals, wild animals, and humans. Differential diagnosis of Sarcoptes varieties is key for epidemiological studies and for formulation of an eradication program. Host-parasite interaction at the systemic level is very important to understand the pathogenicity of the mite. This communication deals with the preliminary report on the genetic characterization of S. scabiei from India. Moreover, the effect of S. scabiei infestation on host physiology with special emphasis on serum biochemical parameters, lipid profile, oxidant/antioxidant balance, stress parameters, and immune responses were evaluated in a porcine model. Cytochrome C oxidase 1 and voltage-sensitive sodium channel based phylogenetic study could distinguish human and animals isolates but could not distinguish host or geographical specific isolates belonging to animal origin. An absence of host-specific cluster among animal isolates argues against the hypothesis of delineating S. scabiei as per host origin. Elevated levels of markers of liver function such as albumin, AST, ALT, ALP, and LDH in infested animals indicated impaired liver function in infested animals. S. scabiei infestation induced atherogenic dyslipidemia indicated by elevated levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides, and a decreased level of high-density lipoprotein cholesterol. Oxidative stress in infested animals was indicated by a high level of nitric oxide and serum MDA as oxidative stress markers and low antioxidant capacity. S. scabiei triggered stress response and elevated levels of serum cortisol and heat shock proteins were recorded in infested animals. S. scabiei infestation increased the serum concentration of immunoglobulins and was associated with up-regulation of IL-2, IFN-γ, IL-1β, and IL-4 indicating both Th1 and Th2 response. The results of the study will be helpful for a better understanding of host-parasite interaction at the systemic level in crusted scabies in pigs.

High-quality nuclear genome for Sarcoptes scabiei-A critical resource for a neglected parasite

The parasitic mite Sarcoptes scabiei is an economically highly significant parasite of the skin of humans and animals worldwide. In humans, this mite causes a neglected tropical disease (NTD), called scabies. This disease results in major morbidity, disability, stigma and poverty globally and is often associated with secondary bacterial infections. Currently, anti-scabies treatments are not sufficiently effective, resistance to them is emerging and no vaccine is available. Here, we report the first high-quality genome and transcriptomic data for S. scabiei. The genome is 56.6 Mb in size, has a a repeat content of 10.6% and codes for 9,174 proteins. We explored key molecules involved in development, reproduction, host-parasite interactions, immunity and disease. The enhanced 'omic data sets for S. scabiei represent comprehensive and critical resources for genetic, functional genomic, metabolomic, phylogenetic, ecological and/or epidemiological investigations, and will underpin the design and development of new treatments, vaccines and/or diagnostic tests.

Scabies: Diagnostic and Therapeutic Update

BACKGROUND

Scabies is globally ubiquitous and is a significant health issue for institutions, the economically disenfranchised, resource-poor areas, and for those with weakened immune systems. Topicals are usually effective, but are cumbersome and expensive to use in large populations and for those nonadherent to topicals. Oral ivermectin became available in Canada for the off-label treatment of scabies in the fall 2018.

OBJECTIVES

To review the diagnosis and management of scabies. Dose schedules and concomitant management measures are outlined for scabies simplex and for crusted scabies. Ivermectin use is outlined.

METHODS

Medline, colleague discussions, practice review, and experience from managing scabies in institutions.

RESULTS

Oral ivermectin is safe, easier to use, cheaper, more effective, and more economical than topicals in widespread institutional scabies, for those nonadherent to topicals, and in crusted scabies.

CONCLUSIONS

Oral ivermectin is the treatment of choice in large populations, the nonadherent, and for crusted scabies. Oral ivermectin is produced by Merck Canada as Stromectol 3 mg. The treatment dose for noncrusted scabies is 200 µg/kg, taken in a single dose with food. For example, 15 mg (5 tablets) for a 70 kg person. Retreat in 10-14 days to enhance effectiveness, and perhaps to reduce scabicide resistance.

Importance of Follow-Up Microscopic Examination in Hospitalized Patients with Confirmed Scabies

We investigated the duration of positive microscopic examination in hospitalized patients with confirmed scabies in an acute care hospital. We included hospitalized patients who were diagnosed with scabies between January 2015 and June 2019. From the study period, a total of 31 patients with confirmed scabies were identified. Median age was 75 years. Of a total of 31 patients with confirmed scabies, six were discharged or transferred before getting a negative microscopic test result. Of the remaining 25 patients with negative microscopic test results, the median duration from diagnosis to a negative microscopic test result was 14 days (interquartile range, 9-17). Given that nosocomial outbreaks lead to high workload and considerable resource consumption, adequate treatment, sufficient follow-up examination, and confirmation of cure are warranted before releasing contact isolation.

Protocol for a cluster-randomised non-inferiority trial of one versus two doses of ivermectin for the control of scabies using a mass drug administration strategy (the RISE study)

INTRODUCTION

Scabies is a significant contributor to global morbidity, affecting approximately 200 million people at any time. Scabies is endemic in many resource-limited tropical settings. Bacterial skin infection (impetigo) frequently complicates scabies infestation in these settings. Community-wide ivermectin-based mass drug administration (MDA) is an effective control strategy for scabies in island settings, with a single round of MDA reducing population prevalence by around 90%. However, current two-dose regimens present a number of barriers to programmatic MDA implementation. We designed the Regimens of Ivermectin for Scabies Elimination (RISE) trial to investigate whether one-dose MDA may be as effective as two-dose MDA in controlling scabies in high-prevalence settings.

METHODS AND ANALYSIS

RISE is a cluster-randomised non-inferiority trial. The study will be conducted in 20 isolated villages in Western Province of Solomon Islands where population prevalence of scabies is approximately 20%. Villages will be randomly allocated to receive either one dose or two doses of ivermectin-based MDA in a 1:1 ratio. The primary objective of the study is to determine if ivermectin-based MDA with one dose is as effective as MDA with two doses in reducing the prevalence of scabies after 12 months. Secondary objectives include the effect of ivermectin-based MDA on impetigo prevalence after 12 and 24 months, the prevalence of scabies at 24 months after the intervention, the impact on presentation to health facilities with scabies and impetigo, and the safety of one-dose and two-dose MDA.

ETHICS AND DISSEMINATION

This trial has been approved by the ethics review committees of the Solomon Islands and the Royal Children's Hospital, Australia. Results will be disseminated in peer-reviewed publications and in meetings with the Solomon Islands Ministry of Health and Medical Services and participating communities.

TRIAL REGISTRATION DETAILS

Australian New Zealand Clinical Trials Registry: ACTRN12618001086257. Date registered: 28 June 2018.

The scabicide effect of moxidectin in vitro and in experimental animals: Parasitological, histopathological and immunological evaluation

Scabies is considered one of the commonest dermatological diseases that has a global health burden. Current treatment with ivermectin (IVM) is insufficient and potential drug resistance was noticed. Moxidectin (MOX), with a better pharmacological profile may be a promising alternative. The efficacy of moxidectin against Sarcoptes scabiei was assessed both in vitro and in vivo in comparison with ivermectin. For the in vitro assay, both drugs were used in two concentrations (50 μg/ml and 100 μg/ml). For the in vivo assay, twenty rabbits infected with Sarcoptes scabiei were divided into three groups: untreated, moxidectin-treated and ivermectin-treated with the same dose of 0.3 mg/kg once. Another four rabbits were used as a normal control non-infected group. Treatment efficacy was evaluated by clinical assessment, parasitological evaluation and histopathological examination of skin samples using Hematoxylin and eosin and toluidine blue for mast cell staining. Immune response was also assessed by immunohistochemical staining of CD3 T cells in skin samples. Our results showed that moxidectin had a high efficacy (100%) in killing mites when used in both concentrations (50 μg/ml, 100 μg/ml) in the in vitro assay. Concerning the in vivo assay, on day 14 post-treatment, all MOX-treated rabbits were mite-free with full clinical cure by the end of the study (D21) showing (100%) reduction of mites count. Also, marked improvement in the epidermis with absence of mites in skin samples were shown. Poor clinical and parasitological improvements were noted in the ivermectin-treated rabbits, when given as a single dose with a percentage reduction (60.67%) in the 2nd week and progressive increase in lesions and mites count in the 3rd week post-treatment. Regarding the immune response, MOX-treated group showed mild infiltration with both mast cells and CD3 T cells in comparison to severe infiltration with both types of cells in the untreated and IVM-treated group. On conclusion, our results demonstrated that a single dose of MOX was more effective than IVM, supporting MOX as a valuable therapeutic approach for scabies therapy.

The in vitro antibacterial effect of permethrin and formaldehyde on Staphylococcus aureus

Antibiotic‐resistant strains of bacteria such as methicillin‐resistant Staphylococcus aureus are a threat to human health, and effective treatment options against them are needed. This study aimed to determine whether the insecticide permethrin was capable of inhibiting the growth of S. aureus or if some other component of a permethrin cream was responsible for a decrease in scabies associated bacterial infection previously observed. Ten S. aureus strains were grown in the presence of permethrin and formaldehyde both alone and in combination with percent inhibition determined by viable counts. Also, a time‐kill assay was conducted on S. aureus exposed to the same conditions. Finally, the morphology of S. aureus grown in the presence of permethrin was examined by scanning electron microscopy. Bacterial inhibition by permethrin ranged from 0% to 41% whereas inhibition by formaldehyde was 100%. The time‐kill curves of permethrin exposed cells were very similar to the positive growth control while the formaldehyde and combination exposure showed complete inhibition even at the 0‐hr time point. The scanning electron micrographs of permethrin grown S. aureus showed healthy cocci cells with no sign of cell damage. Our results show that permethrin is not capable of inhibiting the growth of bacteria enough for it to be termed bactericidal. Formaldehyde is a known antiseptic and therefore was responsible for the antibacterial effect observed after the use of permethrin cream.

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.

Risk Factors for Acute Rheumatic Fever: Literature Review and Protocol for a Case-Control Study in New Zealand

Acute rheumatic fever (ARF) and its sequela, rheumatic heart disease (RHD), have largely disappeared from high-income countries. However, in New Zealand (NZ), rates remain unacceptably high in indigenous Māori and Pacific populations. The goal of this study is to identify potentially modifiable risk factors for ARF to support effective disease prevention policies and programmes. A case-control design is used. Cases are those meeting the standard NZ case-definition for ARF, recruited within four weeks of hospitalisation for a first episode of ARF, aged less than 20 years, and residing in the North Island of NZ. This study aims to recruit at least 120 cases and 360 controls matched by age, ethnicity, gender, deprivation, district, and time period. For data collection, a comprehensive pre-tested questionnaire focussed on exposures during the four weeks prior to illness or interview will be used. Linked data include previous hospitalisations, dental records, and school characteristics. Specimen collection includes a throat swab (Group A Streptococcus), a nasal swab (Staphylococcus aureus), blood (vitamin D, ferritin, DNA for genetic testing, immune-profiling), and head hair (nicotine). A major strength of this study is its comprehensive focus covering organism, host and environmental factors. Having closely matched controls enables the examination of a wide range of specific environmental risk factors.

Review of Scabies in the Elderly

Scabies, an ectoparasitic infestation of the skin by the mite Sarcoptes scabiei, is a clinical problem of particular significance in the elderly population because of unique vulnerability factors. Such factors include reduced mobility, residency in grouped living facilities, and difficulty with implementation of certain treatments. There is also risk of transmission to nearby caretakers and cohabitants. Furthermore, the diagnosis of scabies can be difficult, as this condition can closely resemble other dermatologic diseases. Complicating the diagnosis in this group is the variety of medical settings in which these patients are evaluated, some of which may not be equipped to follow diagnostic guidelines. The diagnosis itself can be complex because of varying clinical presentation and mite burden. Finally, the transmissibility of scabies, especially in grouped living arrangements, makes prompt and proper treatment of this condition paramount. All of these factors present a unique challenge for the clinician treating elderly patients. This article aims to describe the susceptibility factors, clinical presentation, diagnosis, and management considerations specific to elderly adults with scabies.

Formaldehyde as an alternative to antibiotics for treatment of refractory impetigo and other infectious skin diseases

Introduction: Antibiotic-resistant strains of bacteria are an increasing problem in hospitals and in the community. This has resulted in bacterial infections such as impetigo becoming difficult to treat. Alternative treatment options are needed. Areas covered: In this paper, a past study that assessed the health burden of scabies in North Queensland is described and from it, the potential for formaldehyde as an alternative antimicrobial treatment is discussed. In doing so, antibiotic resistance, impetigo, permethrin, and formaldehyde are introduced and the current understanding and limitations of the effects of formaldehyde on humans are outlined. The limited cases of formaldehyde resistance in bacteria are also discussed. Expert opinion: Formaldehyde is currently used as a preservative in cosmetics and medicinal creams due to its antibacterial activity. It, therefore, has the potential to be used as an alternative antibacterial treatment for infections with antibiotic-resistant bacteria. The harmful side effects of airborne formaldehyde and exposure in allergic individuals have been extensively studied. Significantly less research has been conducted on formaldehyde skin contact in healthy individuals. If formaldehyde is safe for topical use in humans, it has the potential to assist with combating antibiotic resistance.

Dermatologic Problems Commonly Seen by the Allergist/Immunologist

Allergists/immunologists see a variety of skin disorders, some of which have a known immunologic basis whereas others do not. We review the prevalence, etiology, clinical presentation, and effective and low-cost care of common dermatologic conditions seen in outpatient practices. Conditions discussed include pityriasis alba, seborrheic dermatitis, rosacea, acne, tinea infections, intertrigo, lichen planus, tinea versicolor, lichen simplex chronicus, scabies, pityriasis rosea, keratosis pilaris, and seborrheic keratosis. An understanding of frequently encountered cutaneous diseases and their therapies will help provide immediate access to treatment and improve the experience for both the affected patient and the clinician.

Ivermectin Impairs the Development of Sexual and Asexual Stages of Plasmodium falciparum In Vitro

Ivermectin is the drug of choice for many parasitic infections, with more than one billion doses being distributed in onchocerciasis programs. The drug has been put into focus recently by the malaria community because of its potential to kill blood-sucking mosquitoes, thereby reducing malaria transmission. However, the activity of ivermectin against the malaria parasite itself has been only partly investigated. This study aimed to investigate the in vitro activity of ivermectin against asexual and sexual stages of Plasmodium falciparum Both asexual and late-stage gametocytes were incubated with ivermectin and control drugs in vitro The growth-inhibiting effects were assessed for asexual stages of different Plasmodium falciparum laboratory strains and culture-adapted clinical isolates using the histidine-rich protein 2 enzyme-linked immunosorbent assay technique. The effect against stage IV/V gametocytes was evaluated based on ATP quantification. Ivermectin showed activities at nanomolar concentrations against asexual stages (50% inhibitory concentration of ∼100 nM) and stage IV/V gametocytes (500 nM) of P. falciparum Stage-specific assays suggested that ivermectin arrests the parasite cycle at the trophozoite stage. Ivermectin might add a feature to its "wonder drug" properties with activity against asexual stages of the malaria parasite Plasmodium falciparum The observed activities might be difficult to reach with current regimens but will be more relevant with future high-dose regimens under investigation. Further studies should be performed to confirm these results in vitro and in vivo.

Crusted scabies in a renal transplant recipient treated with daily ivermectin: A case report and literature review

Crusted scabies is a rare disease variant associated with T-cell dysregulation. Transplant patients are at risk of developing crusted scabies as a consequence of their immunosuppressive regimens. We report a case of crusted scabies presenting with recurrent septicemia in a 65-year-old renal transplant recipient, treated with daily ivermectin for 7 days after initial failure of weekly ivermectin dosing. A literature review of crusted scabies in transplant recipients consisting of 19 cases reports was summarized. Pruritus was common, and initial misdiagnosis was frequent. Most were treated with topical therapy, with one-third receiving ivermectin. Three of seven cases presenting with a concomitant infection died. Crusted scabies is commonly misdiagnosed in transplant recipients owing to its rarity, varied appearance, and different skin distributions. It should be considered in the differential diagnosis of transplant recipients presenting with rash and pruritus, given its association with secondary infection and subsequent mortality.

A systematic review of scabies transmission models and data to evaluate the cost-effectiveness of scabies interventions

Background

Scabies is a common dermatological condition, affecting more than 130 million people at any time. To evaluate and/or predict the effectiveness and cost-effectiveness of scabies interventions, disease transmission modelling can be used.

Objective

To review published scabies models and data to inform the design of a comprehensive scabies transmission modelling framework to evaluate the cost-effectiveness of scabies interventions.

Methods

Systematic literature search in PubMed, Medline, Embase, CINAHL, and the Cochrane Library identified scabies studies published since the year 2000. Selected papers included modelling studies and studies on the life cycle of scabies mites, patient quality of life and resource use. Reference lists of reviews were used to identify any papers missed through the search strategy. Strengths and limitations of identified scabies models were evaluated and used to design a modelling framework. Potential model inputs were identified and discussed.

Findings

Four scabies models were published: a Markov decision tree, two compartmental models, and an agent-based, network-dependent Monte Carlo model. None of the models specifically addressed crusted scabies, which is associated with high morbidity, mortality, and increased transmission. There is a lack of reliable, comprehensive information about scabies biology and the impact this disease has on patients and society.

Discussion

Clinicians and health economists working in the field of scabies are encouraged to use the current review to inform disease transmission modelling and economic evaluations on interventions against scabies.

Scabies is a neglected tropical disease affecting more than 130 million people, with major costs on health care systems worldwide. While effective treatments exist, it is unknown which treatment strategies result in the best outcomes against the lowest costs, and to what extent this differs between communities. Health economic modelling can help answer these questions, but has rarely been used in this disease area. This review discusses all available scabies transmission models (n = 4), and uses them to create a new, comprehensive modelling framework. This framework can be used as aid for creating a scabies transmission model, the details of which will be determined by the context (population) and the question being addressed. The current paper also reviews the data that is needed to inform scabies modelling: on scabies biology, quality of life and resource use. Unfortunately, available data is limited and particularly data on crusted scabies (associated with high morbidity and mortality rates) is rare. With this review, we hope to assist researchers and policy makers to predict and/or evaluate the cost-effectiveness of interventions against scabies in their population(s) of interest. To tackle scabies, it is key to use effective treatment strategies in a cost-effective and sustainable way. The models and data described in this review, may help researchers, clinicians and funding bodies to facilitate this.

Cyclooctatetraene: A Bioactive Cubane Paradigm Complement

Cubane was recently validated as a phenyl ring (bio)isostere, but highly strained caged carbocyclic systems lack π character, which is often critical for mediating key biological interactions. This electronic property restriction associated with cubane has been addressed herein with cyclooctatetraene (COT), using known pharmaceutical and agrochemical compounds as templates. COT either outperformed or matched cubane in multiple cases suggesting that versatile complementarity exists between the two systems for enhanced bioactive molecule discovery.

Infected with Scabies Again? Focus in Management in Long-Term Care Facilities

Scabies is a significant public health condition in long-term care facilities, plaguing even developed countries. Although treatments are available, eradication and control of scabies cases still remain a challenge due to delays in diagnosis and difficulties in maintaining preventive and surveillance measures. Prompt treatment of patients and their contacts that are affected, along with concomitant education of health staff and family members, are paramount. Environmental disinfestation is also a concern.

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.