Risk factors for scabies in hospital: a systematic review.

BACKGROUND: Annually, 175.4 million people are infected with scabies worldwide. Although parasitic infections are important nosocomial infections, they are unrecognized compared to bacterial, fungal, and viral infections. In particular, nonspecific cutaneous manifestations of scabies lead to delayed diagnosis and frequent nosocomial transmission. Hospital-based studies on the risk factors for scabies have yet to be systematically reviewed. METHODS: The study followed the PRISMA guidelines and was prospectively registered in PROSPERO (CRD42023363278). Literature searches were conducted in three international (PubMed, Embase, and CINAHL) and four Korean (DBpia, KISS, RISS, and Science ON) databases. We included hospital-based studies with risk estimates calculated with 95% confidence intervals for risk factors for scabies infection. The quality of the studies was assessed using the Joanna Briggs Institute critical appraisal tools. Two authors independently performed the screening and assessed the quality of the studies. RESULTS: A total of 12 studies were included. Personal characteristics were categorized into demographic, economic, residential, and behavioral factors. The identified risk factors were low economic status and unhygienic behavioral practices. Being a patient in a long-term care facility or institution was an important factor. Frequent patient contact and lack of personal protective equipment were identified as risk factors. For clinical characteristics, factors were categorized as personal health and hospital environment. People who had contact with itchy others were at higher risk of developing scabies. Patients with higher severity and those with a large number of catheters are also at increased risk for scabies infection. CONCLUSIONS: Factors contributing to scabies in hospitals range from personal to clinical. We emphasize the importance of performing a full skin examination when patients present with scabies symptoms and are transferred from settings such as nursing homes and assisted-living facilities, to reduce the transmission of scabies. In addition, patient education to prevent scabies and infection control systems for healthcare workers, such as wearing personal protective equipment, are needed.

The most effective systemic treatment in dogs with sarcoptic mange: a critically appraised topic.

BACKGROUND: Sarcoptic mange is a common, pruritic parasitic skin disease of dogs. Due to its highly contagious character, it represents a potential veterinary and public health risk. Because of clinical similarity with other diseases, cross-antigenicity, and low sensitivity of available diagnostic methods, therapeutical trial is frequently used to confirm the disease. Considering the variety of available acaricidal molecules as well as the need to use the most effective treatment, the present paper reviews evidence comparing different types of systemic treatment of canine scabies. RESULTS: Analysis of the results showed that afoxolaner, fluralaner and sarolaner as well as several macrocyclic lactones such as selamectin, moxidectin and milbemycin oxime can lead to parasitological and clinical cure. CONCLUSION: The similarity in the clinical and parasitological efficacy of these substances enhances the need for comparative studies, which could allow the identification of the most efficacious product.

Immune mechanisms in human Sarcoptes scabiei (Acari: Sarcoptidae) infestations.

Scabies is a parasitic infestation of human and animal skin caused by different strains of the itch mite, Sarcoptes scabiei. The World Health Organization (WHO) has declared scabies in human as a neglected tropical disease, and today over 200 million people worldwide are affected. The two most commonly reported clinical manifestation of the condition are ordinary (OS) and crusted scabies (CS). CS, which can lead to fatal consequences due to secondary bacterial infections, is mostly observed in immunocompromised subjects but can also, although rarely, be detected in immunocompetent individuals. Innate and adaptive immune system components are involved in protection and pathogenesis of scabies, although with some differences between OS and CS. While the cutaneous immune response is dominated by CD4+ T-cells in OS, it is mainly mediated by CD8+ T-cells in CS. The two clinical conditions also differ in CD4+ T-cell-mediated immune responses with mixed TH 1/TH 2 (protective) and TH 2/TH 17 (non-protective) immunoprofiles in OS and CS, respectively. Moreover, the development of CS is associated with early immunosuppression that is followed by deleterious immune response to uncontrolled mite proliferation. However, the immune response to scabies still needs further attention due to inconsistent results in the literature. The aim of this study is to attract more attention to this area by summarizing the current literature on innate and adaptive immune responses triggered against S. scabiei mites.

Evidence underscoring immunological and clinical pathological changes associated with Sarcoptes scabiei infection: synthesis and meta-analysis.

BACKGROUND: Sarcoptes scabiei is one of the most impactful mammalian parasites. There has been much research on immunological and clinical pathological changes associated with S. scabiei parasitism across a range of host species. This rich body of literature is complex, and we seek to bring that complexity together in this study. We first (1) synthesise narrative reviews of immunopathological relationships to S. scabiei infection to construct overarching hypotheses; then (2) undertake a systematic meta-analysis of primary literature on immunological and clinical pathological changes; and lastly (3) contrast our findings from the meta-analysis to our synthesis from narrative reviews. METHODS: We synthesised 55 narrative reviews into two overarching hypotheses representing type I and type IV immune responses to S. scabiei infection. We then systematically extracted all literature reporting immunological variables, acute phase proteins, oxidant/antioxidant status, and erythrocytic, hepatological and nephrological changes, calculating 565 effect sizes between controls and sarcoptic mange affected groupings, refining (simplifying) hypotheses from narrative reviews. RESULTS: Immunological and clinical pathological parameters were most often studied in dogs (n = 12) and humans (n = 14). Combining immunological and clinical pathological information across mammalian species (n = 19) helped yield general insights into observed disease responses. This is evidenced by interspecific consensus in 27 immunological and clinical pathology variables (6/26 type I hypersensitivity, 3/20 type IV hypersensitivity, 6/10 oxidant/antioxidant status, 3/6 acute phase protein, 4/7 erythrocytic, and 5/10 hepatological/nephrological). CONCLUSIONS: Elevated IgE, eosinophils and mast cells in type I hypersensitivity response corresponded to what was described in narrative reviews. Results from type IV hypersensitivity response suggested typical antibody response, however cell-mediated response was less evident. Some consensus of acute phase protein response and shifted oxidant/antioxidant balance and slight evidence of anemia. We highlight the need for mange/scabies studies to more routinely compare immunological and clinical pathological changes against controls, and include collection of a more standardised suite of variables among studies.

Can we increase the success of scabies treatment? The effect of removing tunnels from patients in the success of scabies treatment.

Recently, there has been an increase in scabies infestations. Moreover, the number of patients who do not benefit from conventional treatment regimens is increasing rapidly worldwide. This situation leads clinicians to seek new treatments. To evaluate the contribution of mechanical parasite removal to treatment success when applied prior to topical permethrin 5% treatment. The mechanical removal process was applied once during diagnosis. Two groups of 30 people each were included in the study. Permethrin treatment was given directly to the first group without any procedure. In the second group, the maximum number of tunnels that could be detected were removed from patients. After this procedure, the group received permethrin treatment. All patients were called for control after 10 days, and treatment response rates were evaluated. Sixteen (53.3%) patients who received permethrin treatment directly without any procedure responded to the treatment. In the remaining 14 (46.6%) patients, tunnels and Sarcoptes mites were still present. In the second group, which underwent tunnel removal, complete recovery was observed in 26 (86.6%) patients. The patients who did not benefit from the treatment in the study group had relatively less tunnel removal from their bodies. Removing the tunnel from the patient before the treatment increases the success of the treatment. Considering that there are 8-10 parasites on average in scabies patients, it has been determined that the tunnel removal method is not difficult and contributes to therapeutic success.

The genetic characteristics of Sarcoptes scabiei from Chinese serow (Capricornis milneedwardsii) and goral (Naemorhedus goral arnouxianus) compared with other mites from different hosts and geographic locations using ITS2 and cox1 sequences.

Scabies is a common parasitic disease in many mammalian species, caused by the infestation of Sarcoptes scabiei. There is no consistent conclusion on whether Sarcoptes mites from different hosts or geographic locations have apparent genetic divergence. In this study, we collected and morphologically identified S. scabiei from Chinese serow and goral, and we described the genetic diversity of S. scabiei and other mites based on phylogenetic analyses of the ITS2 and cox1 sequence fragments, including data available in GenBank. The mites isolated from Chinese serow and goral were S. scabiei, and they were morphologically similar. The phylogenetic trees and haplotype networks showed that S. scabiei from other locations worldwide did not cluster according to host divergence or geographical distribution. Additionally, the Fst values were - 0.224 to 0.136 and - 0.045 to 1 between S. scabiei from different hosts, including humans and domestic and wild animals, based on partial ITS and cox1 sequences. Worldwide S. scabiei samples formed three clusters (with H2, H5, and H12 at their centers) in the ITS and one cluster (with C9 at the center) in the cox1 haplotype phylogenetic network. The S. scabiei collected from Chinese serow and goral were morphologically similar and had the same genotype. A study on the genetic characteristics of S. scabiei from Chinese serow and goral together with other mites from different hosts and geographic locations around the world showed no obvious divergence. These findings indicated that scabies likely is a zoonotic disease and that the global prevalence of scabies is probably related to the worldwide trade of domestic animals.

Effects of Sarcoptes scabiei Translationally Controlled Tumor Protein (TCTP) on Histamine Release and Degranulation of KU812 Cells.

Scabies is a common parasitic dermatological infection worldwide that is often neglected. Scabies mites stimulate host inflammatory symptoms via secreted and excreted proteins, which induce basophil and mast cell degranulation and host histamine release. However, the mechanism of degranulation and histamine release is unclear. Moreover, the Sarcoptes scabiei translationally controlled tumor protein (TCTP) is predicted as an excreted protein, which may be involved in host inflammatory response regulation. First, we evaluated S. scabiei TCTP gene (SsTCTP) transcription in larvae, nymphs, and adults by qRT-PCR, and SsTCTP transcription was highest in larvae, followed by nymphs. Second, we found that the S. scabiei TCTP recombinant protein (rSsTCTP) promoted mice histamine release in vivo by Evans blue Miles assay. Therefore, to further explore the possible role of S. scabiei TCTP in host inflammatory response regulation, we established a degranulation model of KU812 cells. The results of the degranulation model suggested that rSsTCTP could induce enhanced degranulation of KU812 cells and increase the secretion of histamine and the expression of IL-4, IL-6, and IL-13 in vitro. In conclusion, we speculate that scabies mites could stimulate host histamine release and Th2 response by excreting S. scabiei TCTP.

Evidence that Transcriptional Alterations in Sarcoptes scabiei Are under Tight Post-Transcriptional (microRNA) Control.

Here, we explored transcriptomic differences among early egg (Ee), late egg (Le) and adult female (Af) stages of the scabies mite, Sarcoptes scabiei, using an integrative bioinformatic approach. We recorded a high, negative correlation between miRNAs and genes with decreased mRNA transcription between the developmental stages, indicating substantial post-transcriptional repression; we also showed a positive correlation between miRNAs and genes with increased mRNA transcription, suggesting indirect post-transcriptional regulation. The alterations in mRNA transcription between the egg and adult female stages of S. scabiei were inferred to be linked to metabolism (including carbohydrate and lipid degradation, amino acid and energy metabolism), environmental information processing (e.g., signal transduction and signalling molecules), genetic information processing (e.g., transcription and translation) and/or organismal systems. Taken together, these results provide insight into the transcription of this socioeconomically important parasitic mite, with a particular focus on the egg stage. This work encourages further, detailed laboratory studies of miRNA regulation across all developmental stages of S. scabiei and might assist in discovering new intervention targets in the egg stage of S. scabiei.

Essential Oils against Sarcoptes scabiei.

Herbal remedia are widely employed in folk medicine, and have been more and more often studied and considered in the treatment of several infections. Sarcoptic mange (scabies, when referring to human patients) is a highly contagious skin disease caused by Sarcoptes scabiei (sarcoptiformes, Sarcoptinae), an astigmatid mite which burrows into the epidermis, actively penetrating the stratum corneum. This parasitosis negatively affects livestock productions and represents a constraint on animal and human health. The treatment relies on permethrine and ivermectine but, since these molecules do not have ovicidal action, more than a single dose should be administered. Toxicity, the possible onset of parasite resistance, the presence of residues in meat and other animal products and environmental contamination are the major constraints. These shortcomings could be reduced by the use of plant extracts that have been in vitro or in vivo checked against these mites, sometimes with promising results. The aim of the present study was to review the literature dealing with the treatment of both scabies and sarcoptic mange by plant-derived agents, notably essential oils.

Parasites of wombats (family Vombatidae), with a focus on ticks and tick-borne pathogens.

Ticks (Arachnida: Acari) are vectors for pathogens and the biggest threat to animal health. Many Australian ticks are associated with pathogens that impact humans, domestic animals and livestock. However, little is known about the presence or impact of tick-borne pathogens in native Australian wildlife. Wombats are particularly susceptible to the effects of the ectoparasite Sarcoptes scabiei which causes sarcoptic mange, the reason for which is unknown. Factors such as other ectoparasites and their associated pathogens may play a role. A critical understanding of the species of ectoparasites that parasitise wombats and their pathogens, and particularly ticks, is therefore warranted. This review describes the ectoparasites of wombats, pathogens known to be associated with those ectoparasites, and related literature gaps. Pathogens have been isolated in most tick species that typically feed on wombats; however, there are minimal molecular studies to determine the presence of pathogens in any other wombat ectoparasites. The development of next-generation sequencing (NGS) technologies allows us to explore entire microbial communities in ectoparasite samples, allowing fast and accurate identification of potential pathogens in many samples at once. These new techniques have highlighted the diversity and uniqueness of native ticks and their microbiomes, including pathogens of potential medical and veterinary importance. An increased understanding of all ectoparasites that parasitise wombats, and their associated pathogens, requires further investigation.

Treatment of sarcoptic and chorioptic mange in an alpaca (Vicugna pacos) herd with a combination of topical amitraz and subcutaneous ivermectin.

Clinical history: An outbreak of intense pruritus and weight loss in a herd of 40 alpacas (Vicugna pacos) in the south-west of France was investigated after the death of 14 adults. One alpaca was referred to a veterinary teaching hospital for diagnosis and treatment but died soon after and one of the dead alpacas was submitted for necropsy. Clinical findings: The remaining alpacas were intensely pruritic with variably severe and extensive alopecia, erythema, lichenification and crusting on the face, ventral abdomen and distal limbs. Superficial skin scrapes from five animals revealed large numbers of Sarcoptes scabiei mites, and less frequent and numerous Chorioptes bovis mites. Coproscopic examinations revealed a median of 1,350 (min 500, max 8800) strongyle epg. The alpaca admitted for treatment was anaemic and hypoalbuminaemic. Skin scrapes revealed copious S. scabiei and C. bovis mites. The two alpacas examined post-mortem had similar skin lesions to those examined on-farm and were cachexic. One had lung lesions attributed to protostrongylid infestation and its liver contained numerous Dicrocoelium spp. adults. Diagnosis: Sarcoptic and chorioptic mange with secondary superficial bacterial skin infection, associated with severe internal parasitism and underfeeding. Treatment and outcome: All 25 alpacas were treated topically with a 3% chlorhexidine shampoo followed by a 0.025% amitraz wash at the initial visit and then 1, 2, 3, 7 and 9 weeks later. A systemic treatment with S/C 500 µg/kg ivermectin was administered at the initial visit and then 2, 7 and 9 weeks later. The alpacas were treated orally with 50 mg/kg praziquantel to control dicrocoeliosis. Nutritional measures, including increased pasture area and supplemental feeding were simultaneously implemented. Pruritus was reduced 1 week after the start of treatment and had resolved after 2 weeks. After 9 weeks, skin lesions were markedly improved. Six months after the initial visit, skin lesions entirely resolved and superficial skin scrapes, taken from half of the animals, were negative for mites. Clinical relevance: This is the first report of the use of two acaricides combined with a chlorhexidine shampoo to successfully treat simultaneous sarcoptic and chorioptic mange in alpacas.

Prevalence and associated factors of scabies in Ethiopia: systematic review and Meta-analysis.

BACKGROUND: Scabies is an infectious disease that affects the skin caused by the mite Sarcoptes scabiei and it transmitted through close personal contact. Even though it is easily treatable disease, its prevalence is high and continuous as neglected tropical disease of resource-poor settings, and particularly affects young age groups. Despite of these facts, studies conducted in Ethiopia regarding to the prevalence and associated factors for scabies infestation have been highly variable and didn't well compiled. Due to that, the aim of this systematic review and meta-analysis was to estimates the overall prevalence of scabies and associated factors in all age groups in Ethiopia. METHODS: International databases (PubMed/PMC/Midline, EMBASE, CINAHL, Web of Science, Google Scholar, Google and Science Direct) were systematically searched from December 1, 2019, to January 18, 2020. All observational studies noted the prevalence of human scabies and associated factors in Ethiopia were included. Two authors (AG and G.T) independently extracted all necessary data using a standardized data extraction format. The data which is extracted each study were analyzed using STATA Version 14.1. Heterogeneity among the included studies was assessed through the Cochrane Q test statistics and I2 test. Lastly, a random effects meta-analysis model was computed to fix overall prevalence and associated factors of scabies. RESULTS: Twelve studies were included in this meta-analysis after 410 articles retrieved. Of these, eight studies were analyzed for prevalence estimation. The overall prevalence of scabies infestation was 14.5% (95%CI: 1.5, 27.6%) in Ethiopia. Furthermore, the subgroup analysis revealed the highest prevalence was 19.6% in Amhara region. A person from a large family size (OR: 3.1, 95% CI: 1.76, 5.67), and sharing a bed (OR: 3.59, 95%CI: 2.88, 4.47) were significantly associated with scabies. CONCLUSION: This study revealed the prevalence of scabies infestation was 14.5% in Ethiopia which was high. Persons from high family size and any contact with scabies case were factors associated with scabies.

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.

Therapeutic potential of medicinal plants for the management of scabies.

Sarcoptes scabiei (S. scabiei), a parasite mite which causes scabies disease resulting in serious public health concern. The long-term scabies disease can lead to complications such as septicemia, acute post-streptococcal glomerulonephritis, heart disease, and secondary infections. Timely treatment to the affected patients is required to control the disease and get rid of the causative agent. Delayed diagnosis and inappropriate treatment can lead to serious consequences. The most common treatment strategy is the use of allopathic medicines which can immediately relieve the patient but have the drawback of side effects. The safe and cost-effective alternative treatment strategy is the use of medicinal plants which have beneficial therapeutic potential against variety of diseases due to the presence of many bioactive phytoconstituents with no or minimal side effects. For the present review, the published articles describing scabies disease and its phytotherapeutic modalities were searched through different data bases including Google Scholar, PubMed, Medline, and ScienceDirect using the keywords like S. scabiei, prevalence of scabies disease, and phytotherapy of scabies. A large number of medicinal plants, such as Melaleuca alternifolia, Curcuma longa, Azadirachta indica, Rosmarinus officinalis, Capsicum annuum, Cinnamomum camphor, Solanum nigrum, and Eupatorium perfoliatum, have been reviewed for the promising future treatments of scabies. All the studied plants have many bioactive compounds with potential therapeutic effects against scabies and can be utilized for therapeutic purposes for this disease. This literature study has limitations because of the lack of sufficient data due to limited pre-clinical trials in this particular area. This review provides a baseline to explore the therapeutic potential of these medicinal plants against skin diseases. However, extensive studies are required to identify, authenticate, and characterize the bioactive compounds present in these plants which may lead to value addition in pharmaceutical industries providing the cost-effective way of treatment with minimal side effects.

A Tissue Digestion Protocol for Measuring Sarcoptes scabiei (Astigmata: Sarcoptidae) Density in Skin Biopsies.

Sarcoptic mange is a parasitic skin disease caused by the burrowing mite Sarcoptes scabiei that affects a diversity of mammals, including humans, worldwide. In North America, the most commonly affected wildlife includes wild canids, such as coyotes and red foxes, and more recently American black bears in the Mid-Atlantic and Northeast United States. Currently, surveillance for sarcoptic mange in wildlife is syndromic, relying on detection of clinical signs and lesions, such as alopecia and crusting of skin. When possible, skin scrapes are used to identify the causative mite. While skin scrapes are a valuable diagnostic tool to identify mites, this approach has significant limitations when used for quantification of mite burden. To further investigate mite burden in cases of sarcoptic mange, 6-mm punch biopsies were collected from affected skin of red foxes (Vulpes vulpes Linnaeus [Carnivora: Canidae]), a species historically affected by sarcoptic mange, frequently with high mite burdens and severe skin disease, and validated on skin tissue from mange-affected American black bears (Ursus americanus Pallas [Carnivora: Ursidae]) and coyotes (Canis latrans Say [Carnivora: Canidae]). Biopsies were digested by incubating the tissue in potassium hydroxide (KOH) at 55°C. The greatest tissue clearance and lowest mite degradation resulted after 12 h of tissue digestion. The purpose of this manuscript is to describe a methodology for host tissue digestion and mite quantification in cases of sarcoptic mange. This method will provide a valuable surveillance and research tool to better understand sarcoptic mange in wild and domestic animals, with applications to a diversity of other ectoparasitic diseases.

First Infestation Case of Sarcoptic Mange from a Pet Rabbit Oryctolagus Cuniculus in Republic of Korea.

In November 2019 a 5-month-old mixed-breed rabbit presented to Chungbuk National University Veterinary Teaching Hospital, Cheongju-si, Chungbuk, Republic of Korea (Korea) with symptoms comprising pruritus, crusts on skin, poor appetite and reduced defecation. The rabbit was purchased 2 months prior from a pet shop located in a big market, and that the symptoms were first observed about 2 weeks prior to the hospital visit. Physical examination revealed that the patient had crust formation and alopecia on the nose together with lesions on the digits. A skin scraping test was performed using mineral oil and a high density of mites was observed by microscopy. Each mite showed a round, tortoise-like body with 4 comparatively short pairs of legs. The anus was located at the terminal unlike with suspected pathogen, Notoedres cati. Based on morphological characteristics, we identified the mite as Sarcoptes sp. Ivermectin was administered weekly by subcutaneous injection at a dosage of 0.4 mg/kg, and 4 weeks of follow-up study revealed the patient was fully recovered. And no more mites were detected from the case. This is the first case report of sarcoptic mange in a pet rabbit in Korea.

USE OF FLUMETHRIN-IMPREGNATED COLLARS TO MANAGE AN EPIDEMIC OF SARCOPTIC MANGE IN AN URBAN POPULATION OF ENDANGERED SAN JOAQUIN KIT FOXES (VULPES MACROTIS MUTICA).

Sarcoptic mange epidemics can have long-lasting impacts on susceptible wildlife populations, potentially contributing to local population declines and extirpation. Since 2013, there have been 460 reported cases of sarcoptic mange in an urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, CA, with many of them resulting in fatality. As part of a multifaceted response to mitigate mange-caused mortalities and reduce this conservation threat, a 2-yr randomized field trial was conducted to assess the efficacy of long-acting flumethrin collars against sarcoptic mange in kit foxes. Thirty-five kit foxes living in a high-density population on a college campus were captured, examined, administered selamectin, and each fox randomly assigned to either receive a flumethrin collar placed within a VHF radio collar or a VHF radio collar without flumethrin. The survival and mange-infestation status of study animals was monitored via radio telemetry, remote cameras, and periodic recapture examinations and compared among treated and control kit foxes using a Cox proportional hazards model. The average time to onset of mange for treated kit foxes (176 days) was similar to controls (171 days) and treatment with flumethrin did not significantly reduce mange risk for all kit foxes. Kit foxes that had a mild mange infestation at the beginning of the study were four times more likely to develop mange again, regardless of flumethrin treatment, compared with kit foxes that had no signs at initial recruitment. This study demonstrates an approach to evaluating population-level protection and contributes to the limited literature on efficacy, safety, and practicality of acaricides in free-ranging wildlife.

Sarcoptic Mange of Fox Origin in Multiple Farm Animals and Scabies in Humans, Switzerland, 2018.

Fox-derived Sarcoptes scabiei mites caused an outbreak of mange on a farm in Switzerland in 2018. Pruritic skin lesions suggestive of S. scabiei mite infestation developed in 4 humans who had direct contact with affected farm animals but not foxes. Sarcoptic mange is continuously spreading; such outbreaks affecting humans could start occurring more frequently.

Risk factors for treatment failure in scabies: a cohort study.

BACKGROUND: Treatment failure, which occurs in about one-third of cases, is considered as a major factor in the increasing incidence of scabies in developed countries. OBJECTIVES: To identify predictors of treatment failure of scabies in ambulatory populations. METHODS: This multicentre study compared the clinical characteristics and treatment modalities between a group of patients with scabies treated successfully and another group who were not cured 3 months after antiscabies treatment. RESULTS: In total 210 patients with a diagnosis of scabies were included, comprising 98 patients in the treatment success group and 112 in the treatment failure group. The main risk factors for treatment failure were (i) the use of only one type of treatment, topical benzyl benzoate (BB) or oral ivermectin, vs. the combination of both treatments [odds ratio (OR) 2·15, 95% confidence interval (CI) 1·22-3·77]; (ii) the use of a single intake (vs. two) of oral ivermectin (OR 10·2. 95% CI 4·49-23·2); (iii) intake of ivermectin during a meal vs. on an empty stomach (OR 4·31, 95% CI 1·89-9·84); (iv) absence of decontamination of furnishings (OR 8·72, 95% CI 3·50-21·8), in particular sofa and cushions (OR 5·90, 95% CI 2·34-14·9), mattresses (OR 4·16, 95% CI 1·35-12·8) or car seats (OR 6·57, 95% CI 3·27-13·2) and (v) absence of written documents explaining treatment modalities (OR 5·18, 95% CI 2·57-10·4). In multivariate analysis, treatment failure was mainly associated with (i) use of a single intake (vs. two) of ivermectin (OR 6·62, 95% CI 2·71-16·2); (ii) use of BB alone vs. two intakes of ivermectin (OR 3·51, 95% CI 1·55-7·95) and (iii) absence of decontamination of furniture with acaricides (OR 5·81, 95% CI 1·96-16·7). CONCLUSIONS: Use of topical BB alone and a single intake (vs. two) of ivermectin are predictors of treatment failure.