Current treatments for scabies

Design, Synthesis and Bioactivity of Benzyl Propiolates with Broad-Spectrum Inhibition Activity on Phytopathogenic Fungi

As part of our continuing research on propiolic acid derivatives, a series of benzyl propiolate derivatives and analogues were designed, synthesized, and investigated for inhibition activity in vitro and in vivo on phytopathogenic fungi, structure-activity relationship (SAR) and action mechanism. The results showed that most of the compounds had potent and broad-spectrum antifungal activity in vitro at 50 μg/mL. Among the compounds, 2-bromobenzyl propiolate (3h) displayed the highest comprehensive activity with total activity index (TAI) of 4.57 against all the eight test fungi followed by 3-fluorobenzyl propiolate (3c) (TAI = 4.53), superior to positive fungicides thiabendazole (TAI < 4.12) and/or azoxystrobin (TAI < 2.90). Relative to the other fungi, Fusarium solani and Fusarium graminearum revealed higher total susceptibility indexes (TSI) of 11.1 and 8.98, respectively, for all compounds. 3h and 3g (4-chlorobenzyl propiolate) gave the smallest EC50 values of 0.86 and 0.67 μg/mL against F. solani and F. graminearum, respectively, superior or comparable with thiabendazole and azoxystrobin. As a representative, 3h at 200 μg/mL displayed 100% protection on F. solani infections on potatoes over 7 days and high safety for plant growth. In antifungal mechanism, 3h was able to change mycelial morphology, destroy the structures of both hypha and cell membrane, increase the intracellular ROS level, decrease the intracellular mitochondrial membrane potential level, and change the permeability of the cell membrane. The SAR showed that ethynyl is a key group for the activity, and the presence of halogen atoms at the 2-site of the benzene ring can significantly improve the activity in most cases. Thus, benzyl propiolate can be considered a novel antifungal lead compound, while 3h can be considered a promising fungicide candidate to develop new agricultural fungicides.

Comparison of topical permethrin 5% vs. benzyl benzoate 25% treatment in scabies: a double-blinded randomized controlled trial

BACKGROUND

Scabies is a pruritic parasitic infestation of the skin. High-income countries have reported an increasing incidence over the last few years. Studies have indicated a reduction in the sensitivity of scabies mites to the standard treatment of choice, topical permethrin 5%.

OBJECTIVES

To evaluate in a head-to-head manner the efficacy of two topical scabicides [permethrin 5% and benzyl benzoate 25% (BB)] in the treatment of scabies using the same administration modality; and to address potential confounding factors such as incorrectly performed treatment and hygiene measures.

METHODS

In total, 110 patients with dermoscopy-verified scabies infestation were enrolled and randomized into two equally sized groups in a double-blinded manner. Fifty-five received topical permethrin 5% and 55 received topical BB 25%, both for daily use over a period of three consecutive days. Treatment outcome was evaluated by dermoscopy at a 3-week follow-up visit.

RESULTS

Treatment resulted in a dermoscopy-verified cure rate of 27% in the permethrin group and 87% in the BB group. The tolerability and safety profile of permethrin 5% cream was excellent, while the BB emulsion produced a burning sensation in 43% of patients.

CONCLUSIONS

Topical permethrin demonstrated a lack of efficacy in the majority of scabies cases, whereas BB demonstrated an excellent cure rate and reasonable tolerability. Considering the reduced sensitivity of scabies mites to permethrin 5%, our results suggest that BB is an appropriate first-line therapy in the treatment of scabies.

Comparative analysis of the allergenic characteristics and serodiagnostic potential of recombinant chitinase-like protein-5 and -12 from Sarcoptes scabiei

Background

Scabies is caused by burrowing of the mite Sarcoptes scabiei into the stratum corneum. Currently, diagnosis via routine skin scraping is very difficult, and information on the allergenic identification of S. scabiei remains limited.

Methods

We performed comparative analysis of the serological diagnostic potential of recombinant S. scabiei chitinase-like protein-5 (rSsCLP5) and recombinant S. scabiei chitinase-like protein-12 (rSsCLP12) by measuring the levels of serum-specific IgG and IgE antibodies (Abs) as diagnostic markers. In addition, the allergenic characteristics of rSsCLP5 and rSsCLP12 were evaluated using IgE-binding experiments and skin tests.

Results

The IgE Abs-based indirect enzyme-linked immunosorbent assay (ELISA) methods showed high sensitivity and specificity: the rSsCLP5-based assay had 93.5% sensitivity and 94.4% specificity; the rSsCLP12-based assay had 100% sensitivity and 98.1% specificity. The specific IgE Abs in infested mouse sera could bind rSsCLP5 and rSsCLP12. In skin tests, rabbits in the rSsCLP5 and rSsCLP12 groups and positive control (histamine) groups exhibited allergic reactions. Most test sites in the rSsCLP12 group had edema, bleeding spots, and even ulcers or scabs, but such allergy symptoms were rare in the rSsCLP5 group. Moreover, the allergic history rabbit group had more severe allergic reactions and lower levels of IgE Abs compared to the healthy rabbit group in the same protein group.

Conclusions

These findings validate the use of IgE Abs to rSsCLP5 and rSsCLP12 as potentially useful markers for diagnosing scabies. Moreover, both rSsCLP5 and rSsCLP12 have allergenic properties, and the potential allergen rSsCLP12 is a stronger allergen than rSsCLP5.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04654-0.

A scabies outbreak in the North East Region of Ghana: The necessity for prompt intervention

Background

There is a dearth of data on scabies from Ghana. In September 2019, local health authorities in the East Mamprusi district of northern Ghana received reports of scabies from many parts of the district. Due to on-going reports of more cases, an assessment team visited the communities to assess the effect of the earlier individual treatment on the outbreak. The assessment team furthermore aimed to contribute to the data on scabies burden in Ghana and to demonstrate the use of the International Alliance for the Control of Scabies (IACS) diagnostic tool in a field survey in a resource limited setting.

Methodology/Principal findings

This was a cross sectional study. Demographic information and medical history was collected on all participants using a REDCap questionnaire. A standardised skin examination of exposed regions of the body was performed on all participants. Scabies was diagnosed based on the criteria of the International Alliance for the Control of Scabies (IACS). Participants were mostly female (61.5%) and had a median age of 18.8 years (IQR 13–25). Two hundred out of 283 (71%) of participants had scabies with most (47%) presenting with moderate disease. Impetigo was found in 22% of participants with scabies and 10.8% of those without scabies [RR 2.27 (95% CI 1.21–4.27)]. 119 participants who received scabies treatment in the past months still had clinical evidence of the disease. 97% of participants reported a recent scabies contact. Scabies was commoner in participants ≤16 years compared to those >16 years [RR 3.06 (95% CI 1.73–5.45)].

Conclusion/Significance

The prevalence of scabies was extremely high. The lack of a systematic approach to scabies treatment led to recurrence and ongoing community spread. The IACS criteria was useful in this outbreak assessment in Ghana. Alternative strategies such as Mass drug administration may be required to contain outbreaks early in such settings.

Scabies, recently categorised as a Neglected Tropical Disease by the WHO is caused by infestation with Sarcoptes scabiei and is characterised by intense pruritus and rash that typically involves the genitalia and the web spaces of the fingers and toes. It has a large global burden and is associated with significant morbidity and socio-economic burden. Secondary bacterial infections following scabies can lead to significant complications including chronic kidney disease from glomerulonephritis and possibly rheumatic heart disease. An outbreak of scabies was reported in Ghana’s East Mamprusi district in September 2019. Despite earlier treatment of individual cases, scabies prevalence was 71%. About 19% of participants had impetigo which was mostly mild in severity. Absence of a systematic approach to treat scabies led to recurrence and ongoing community spread. The recently published IACS criteria for diagnosing scabies proved useful in this outbreak assessment in Ghana. Alternative strategies such as Mass drug administration may be required to contain outbreaks in such settings.

Comparison of the efficacy of tea tree (Melaleuca alternifolia) oil with other current pharmacological management in human demodicosis: A Systematic Review

Various treatments are found to be moderately effective in managing Demodex-related diseases except tea tree oil (TTO) and terpinen-4-ol (T4O), which showed superior miticidal and anti-inflammatory effects in numerous clinical studies. Their possible effects include lowering mite counts, relieving Demodex-related symptoms, and modulating the immune system. This review summarizes the current clinical topical and oral treatments in human demodicosis, their possible mechanisms of action, side-effects and resistance in treating this condition. TTO (especially T4O) is found to be the most effective followed by metronidazole, ivermectin and permethrin in managing the disease. This is because TTO has anti-parasitic, anti-bacterial, anti-fungal, anti-inflammatory and wound-healing effects. Furthermore, nanoTTO can even release its contents into fungus and Pseudomonas biofilms. Combinations of different treatments are occasionally needed for refractory cases, especially for individuals with underlying genetic predisposal or are immuno-compromised. Although the current treatments show efficacy in controlling the Demodex mite population and the related symptoms, further research needs to be focused on the efficacy and drug delivery technology in order to develop alternative treatments with better side-effects profiles, less toxicity, lower risk of resistance and are more cost-effective.

Ivermectin and permethrin for treating scabies

BACKGROUND

Scabies is an intensely itchy parasitic infection of the skin. It occurs worldwide, but is particularly problematic in areas of poor sanitation, overcrowding, and social disruption. In recent years, permethrin and ivermectin have become the most relevant treatment options for scabies.

OBJECTIVES

To assess the efficacy and safety of topical permethrin and topical or systemic ivermectin for scabies in people of all ages.

SEARCH METHODS

We searched the following databases up to 25 April 2017: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, and IndMED. We searched the World Health Organization International Clinical Trials Registry Platform, the ISRCTN registry, CenterWatch Clinical Trials Listing, ClinicalTrials.gov, TrialsCentral, and the UK Department of Health National Research Register for ongoing trials. We also searched multiple sources for grey literature and checked reference lists of included studies for additional trials.

SELECTION CRITERIA

We included randomized controlled trials that compared permethrin or ivermectin against each other for people with scabies of all ages and either sex.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the identified records, extracted data, and assessed the risk of bias for the included trials.The primary outcome was complete clearance of scabies. Secondary outcomes were number of participants re-treated, number of participants with at least one adverse event, and number of participants withdrawn from study due to an adverse event.We summarized dichotomous outcomes using risk ratios (RR) with 95% confidence intervals (CI). If it was not possible to calculate the point estimate, we described the data qualitatively. Where appropriate, we calculated combined effect estimates using a random-effects model and assessed heterogeneity. We calculated numbers needed to treat for an additional beneficial outcome when we found a difference.We assessed the certainty of the evidence using the GRADE approach. We used the control rate average to provide illustrative clearance rates in the comparison groups.

MAIN RESULTS

Fifteen studies (1896 participants) comparing topical permethrin, systemic ivermectin, or topical ivermectin met the inclusion criteria. Overall, the risk of bias in the included trials was moderate: reporting in many studies was poor. Nearly all studies were conducted in South Asia or North Africa, where the disease is more common, and is associated with poverty.EfficacyOral ivermectin (at a standard dose of 200 μg/kg) may lead to slightly lower rates of complete clearance after one week compared to permethrin 5% cream. Using the average clearance rate of 65% in the trials with permethrin, the illustrative clearance with ivermectin is 43% (RR 0.65, 95% CI 0.54 to 0.78; 613 participants, 6 studies; low-certainty evidence). However, by week two there may be little or no difference (illustrative clearance of permethrin 74% compared to ivermectin 68%; RR 0.91, 95% CI 0.76 to 1.08; 459 participants, 5 studies; low-certainty evidence). Treatments with one to three doses of ivermectin or one to three applications of permethrin may lead to little or no difference in rates of complete clearance after four weeks' follow-up (illustrative cures with 1 to 3 applications of permethrin 93% and with 1 to 3 doses of ivermectin 86%; RR 0.92, 95% CI 0.82 to 1.03; 581 participants, 5 studies; low-certainty evidence).After one week of treatment with oral ivermectin at a standard dose of 200 μg/kg or one application of permethrin 5% lotion, there is probably little or no difference in complete clearance rates (illustrative cure rates: permethrin 73%, ivermectin 68%; RR 0.93, 95% CI 0.74 to 1.17; 120 participants, 1 study; moderate-certainty evidence). After two weeks of treatment, one dose of systemic ivermectin compared to one application of permethrin lotion may lead to similar complete clearance rates (extrapolated cure rates: 67% in both groups; RR 1.00, 95% CI 0.78 to 1.29; 120 participants, 1 study; low-certainty evidence).There is probably little or no difference in rates of complete clearance between systemic ivermectin at standard dose and topical ivermectin 1% lotion four weeks after initiation of treatment (illustrative cure rates: oral ivermectin 97%, ivermectin lotion 96%; RR 0.99, 95% CI 0.95 to 1.03; 272 participants, 2 studies; moderate-certainty evidence). Likewise, after four weeks, ivermectin lotion probably leads to little or no difference in rates of complete clearance when compared to permethrin cream (extrapolated cure rates: permethrin cream 94%, ivermectin lotion 96%; RR 1.02, 95% CI 0.96 to 1.08; 210 participants, 1 study; moderate-certainty evidence), and there is little or no difference among systemic ivermectin in different doses (extrapolated cure rates: 2 doses 90%, 1 dose 87%; RR 0.97, 95% CI 0.83 to 1.14; 80 participants, 1 study; high-certainty evidence).SafetyReporting of adverse events in the included studies was suboptimal. No withdrawals due to adverse events occurred in either the systemic ivermectin or the permethrin group (moderate-certainty evidence). Two weeks after treatment initiation, there is probably little or no difference in the proportion of participants treated with systemic ivermectin or permethrin cream who experienced at least one adverse event (55 participants, 1 study; moderate-certainty evidence). After four weeks, ivermectin may lead to a slightly larger proportion of participants with at least one adverse event (extrapolated rates: permethrin 4%, ivermectin 5%; RR 1.30, 95% CI 0.35 to 4.83; 502 participants, 4 studies; low-certainty evidence).Adverse events in participants treated with topical ivermectin were rare and of mild intensity and comparable to those with systemic ivermectin. For this comparison, it is uncertain whether there is any difference in the number of participants with at least one adverse event (very low-certainty evidence). No withdrawals due to adverse events occurred (62 participants, 1 study; moderate-certainty evidence).It is uncertain whether topical ivermectin or permethrin differ in the number of participants with at least one adverse event (very low-certainty evidence). We found no studies comparing systemic ivermectin in different doses that assessed safety outcomes.

AUTHORS' CONCLUSIONS

We found that for the most part, there was no difference detected in the efficacy of permethrin compared to systemic or topical ivermectin. Overall, few and mild adverse events were reported. Our confidence in the effect estimates was mostly low to moderate. Poor reporting is a major limitation.

Expression and characterisation of a Sarcoptes scabiei protein tyrosine kinase as a potential antigen for scabies diagnosis

Scabies is a disease that harms humans and other animals that is caused by the itch mite Sarcoptes scabiei burrowing into the stratum corneum of the skin. In the early stages of scabies, symptoms are often subclinical and there are no effective diagnostic methods. Herein, we cloned, expressed and characterised an S. scabiei protein tyrosine kinase (SsPTK) and evaluated its diagnostic value as a recombinant antigen in rabbit during the early stages of Sarcoptes infestation. The SsPTK protein is ~30 kDa, lacks a signal peptide, and shares high homology with a PTK from the rabbit ear mite Psoroptes ovis cuniculi. The protein was widely distributed at the front end of mites, particularly in the chewing mouthparts and legs. Indirect ELISA using recombinant SsPTK showed good diagnostic value, with 95.2% (40/42) sensitivity and 94.1% (48/51) specificity for detecting anti-PTK antibody in serum samples from naturally-infested rabbits. More importantly, PTK ELISA could diagnose infection in the early stages (infestation for 1 week) with an accuracy of 100% (24/24). SsPTK therefore shows potential as a sensitive antigen for the early diagnosis of parasitic mite infestation.

Small Molecule Agonists of Cell Adhesion Molecule L1 Mimic L1 Functions In Vivo

Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery after injury, leading to severe disabilities in motor functions and pain. Peripheral nerve injury impairs motor, sensory, and autonomic functions, particularly in cases where nerve gaps are large and chronic nerve injury ensues. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration after acute injury. We screened libraries of known drugs for small molecule agonists of L1 and evaluated the effect of hit compounds in cell-based assays in vitro and in mice after femoral nerve and spinal cord injuries in vivo. We identified eight small molecule L1 agonists and showed in cell-based assays that they stimulate neuronal survival, neuronal migration, and neurite outgrowth and enhance Schwann cell proliferation and migration and myelination of neurons in an L1-dependent manner. In a femoral nerve injury mouse model, enhanced functional regeneration and remyelination after application of the L1 agonists were observed. In a spinal cord injury mouse model, L1 agonists improved recovery of motor functions, being paralleled by enhanced remyelination, neuronal survival, and monoaminergic innervation, reduced astrogliosis, and activation of microglia. Together, these findings suggest that application of small organic compounds that bind to L1 and stimulate the beneficial homophilic L1 functions may prove to be a valuable addition to treatments of nervous system injuries.

Ectoparasites of medical and veterinary importance: drug resistance and the need for alternative control methods

OBJECTIVES

Despite multiple attempts at eradication, many ectoparasites of humans and domestic livestock remain a persistent problem in the modern world. For many years, a range of pesticide drugs including organophosphates, organochlorides and synthetic pyrethroids provided effective control of these parasites; but intensive use of these drugs has led to the evolution of resistance in many target species. This paper aims to review the effectiveness of current control methods and discuss potential alternatives for the long term sustainable control of ectoparasites.

KEY FINDINGS

Important medical ectoparasites such as scabies mites, head lice and bed bugs present a significant public health problem, and so adequate control methods are essential. Ectoparasites of domestic livestock and farmed fish (for example sheep scab mites, poultry mites and sea lice) are also of concern given the increasing strain on the world's food supply. These parasites have become resistant to several classes of pesticide, making control very difficult. Recently, an increasing amount of research has focussed on alternative control methods such as insect growth regulators, biological control using essential oils or fungi, as well as vaccine development against some ectoparasites of medical and veterinary importance.

SUMMARY

Drug resistance is prevalent in all of the ectoparasites discussed in this review. A wide variety of alternative control methods have been identified, however further research is necessary in order for these to be used to successfully control ectoparasitic diseases in the future.

Scabies and bedbugs in hospital outbreaks

Scabies and bedbugs are two emerging ectoparasitic infections reported in crowded areas, including hospitals. Skin involvement is the main presenting initial manifestation for both infections, and the diagnosis is yet challenging for both. Topical permethrin is considered the first-line therapy for scabies except for crusted scabies which is mainly treated with oral ivermectin. To the contrary, treatment of bedbugs is mainly symptomatic. Avoiding close contact, early diagnosis and treatment of infected persons as well as decontamination of the involved environment play an essential role in controlling outbreaks in healthcare settings.

Diagnosis, prevention, and treatment of scabies

Scabies remains a public health problem, especially in developing countries, with a worldwide incidence of approximately 300 million cases each year. Prolonged skin-to-skin contact is necessary to allow the transmission of the causative mite, Sarcoptes scabiei. Classic scabies presents with burrows, erythematous papules, and generalized pruritus. Clinical variants include nodular scabies and crusted scabies, also called Norwegian scabies. The diagnosis is based mainly on history and physical examination, but definitive diagnosis depends on direct visualization of the mites under microscopy. Alternative diagnostic methods include the burrow ink test, video-dermatoscopy, newly serologic tests like PCR/ELISA, and specific IgE directed toward major mite components. Treatment of scabies consists of either topical permethrin or oral ivermectin, although the optimal regimen is still unclear.

Disease burden and health-care clinic attendances for young children in remote aboriginal communities of northern Australia

OBJECTIVE

To determine the frequency of presentations and infectious-disease burden at primary health care (PHC) services in young children in two remote Aboriginal communities in tropical northern Australia.

METHODS

Children born after 1 January 2001, who were resident at 30 September 2005 and for whom consent was obtained, were studied. Clinic records were reviewed for all presentations between 1 January 2002 and 30 September 2005. Data collected included reason for presentation (if infectious), antibiotic prescription and referral to hospital.

FINDINGS

There were 7273 clinic presentations for 174 children aged 0-4.75 years, 55% of whom were male. The median presentation rate per child per year was 16 (23 in the first year of life). Upper-respiratory-tract infections (32%) and skin infections (18%) were the most common infectious reasons for presentation. First presentations for scabies and skin sores peaked at the age of 2 months. By 1 year of age, 63% and 69% of children had presented with scabies and skin sores, respectively.

CONCLUSION

These Aboriginal children average about two visits per month to PHC centres during their first year of life. This high rate is testament to the disease burden, the willingness of Aboriginal people to use health services and the high workload experienced by these health services. Scabies and skin sores remain significant health problems, with this study describing a previously undocumented burden of these conditions commencing within the first few months of life. Appropriate prevention and treatment strategies should encompass early infancy to reduce the high burden of infectious diseases in this population.

Characterisation of recombinant immunoreactive antigens of the scab mite Sarcoptes scabiei

Sarcoptic mange (or scabies) is an important skin disease which can affect a variety of species including humans, cattle, goats, sheep, horses, pigs, rabbits, and dogs. Approximately 300 million people are affected worldwide and in lifestock animals the infestation may lead to substantial economic losses caused by depression in growth and feed conversion rates. Diagnosis of Sarcoptes infestation is difficult and only a few serological tests have been developed using whole mite antigen for diagnosis of mange in animals. Here we describe the isolation and characterisation of cDNAs of several immunoreactive clones and their recombinant expression in Escherichia coli. Three of the proteins contain repetitive sequences which suggests that they might be involved in immune evasion. The application of these antigens in serodiagnosis and the suitability for diagnosis is discussed.

Scabies: molecular perspectives and therapeutic implications in the face of emerging drug resistance

Limited effective treatments, coupled with recent observations of emerging drug resistance to oral ivermectin and 5% permethrin, raise concerns regarding the future control of scabies, especially in severe cases and in endemic areas where repeated community treatment programs are in place. There is consequently an urgent need to define molecular mechanisms of drug resistance in scabies mites and to develop and assess alternative therapeutic options, such as tea tree oil, in the event of increasing treatment failure. Molecular studies on scabies mites have, until recently, been restricted; however, recent advances are providing new insights into scabies mite biology and genetic mechanisms underlying drug resistance. These may assist in overcoming many of the current difficulties in monitoring treatment efficacy and allow the development of more sensitive tools for monitoring emerging resistance.

Escabiose na cabeça e pescoço: nós a estamos reconhecendo?

Apesar de o acometimento de cabeça e pescoço de crianças mais velhas e adultos na escabiose ser conhecido, a literatura é pobre em sua descrição. Estudados 124 pacientes com escabiose clássica com cinco anos de idade ou mais, para pesquisa, descrição e registro fotográfico das lesões de cabeça e pescoço. Esses locais foram acometidos em 35,8% dos casos, e as lesões mais encontradas foram crostas hemáticas, pápulas eritematosas com e sem escoriações ou crostas sobrepostas e descamação adjacente.

Comparative effect of topical application of lindane and permethrin on oxidative stress parameters in adult scabies patients

OBJECTIVES

The insecticides lindane and permethrin are commonly used for treatment of scabies. Animal studies have shown the presence of insecticide induced oxidative stress. Hence, this study was undertaken to assess and compare the effects of topical application of lindane and permethrin on oxidative stress parameters in scabies patients.

DESIGN AND METHODS

Patients were alternatively assigned to treatment by either 1% lindane lotion or 5% permethrin cream. Blood samples were collected before and 12-14 h after the application of the drugs and evaluated for oxidative stress parameters and compared with healthy controls.

RESULTS

Serum malondialdehyde (MDA) levels, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activity were significantly increased while blood glutathione (GSH) levels were significantly decreased in the lindane group as compared to controls and the permethrin group. The permethrin treated group showed a non significant alteration in the oxidative stress parameters.

CONCLUSION

Topical application of lindane induced significant oxidative stress as compared to permethrin which appears to be a safer option for the treatment of scabies.

Interventions for treating scabies

BACKGROUND

Scabies is an intensely itchy parasitic infection of the skin caused by the Sarcoptes scabiei mite. It is a common public health problem with an estimated global prevalence of 300 million cases. Serious adverse effects have been reported for some drugs used to treat scabies.

OBJECTIVES

To evaluate topical and systemic drugs for treating scabies.

SEARCH STRATEGY

In February 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE, EMBASE, LILACS, and INDMED. In March 2007, we also searched the grey literature and sources for registered trials. We also checked the reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials of drug treatments for scabies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Results were presented as relative risks with 95% confidence intervals and data combined where appropriate.

MAIN RESULTS

Twenty small trials involving 2392 people were included. One trial was placebo controlled, 16 compared two or more drug treatments, two compared treatment regimens, and one compared different drug vehicles.Fewer treatment failures occurred by day seven with oral ivermectin in one small trial (55 participants). Topical permethrin appeared more effective than oral ivermectin (85 participants, 1 trial), topical crotamiton (194 participants, 2 trials), and topical lindane (753 participants, 5 trials). Permethrin also appeared more effective in reducing itch persistence than either crotamiton (94 participants, 1 trial) or lindane (490 participants, 2 trials). One small trial did not detect a difference between permethrin (a synthetic pyrethroid) and a natural pyrethrin-based topical treatment (40 participants). No significant difference was detected in the number of treatment failures between crotamiton and lindane (100 participants, 1 trial), lindane and sulfur (68 participants, 1 trial), benzyl benzoate and sulfur (158 participants, 1 trial), and benzyl benzoate and natural synergized pyrethrins (240 participants, 1 trial); all were topical treatments. No trials of malathion were identified. No serious adverse events were reported. A number of trials reported skin reactions in participants randomized to topical treatments. There were occasional reports of headache, abdominal pain, diarrhoea, vomiting, and hypotension.

AUTHORS' CONCLUSIONS

Topical permethrin appears to be the most effective treatment for scabies. Ivermectin appears to be an effective oral treatment. More research is needed on the effectiveness of malathion, particularly when compared to permethrin, and on the management of scabies in an institutional setting and at a community level.

Percepção da doença e automedicação em pacientes com escabiose

FUNDAMENTOS: A situação de alta prevalência da escabiose, associada ao baixo grau de autodiagnóstico e à estigmatização dos parasitados, contribui para a automedicação. OBJETIVOS: Verificar a percepção dos pacientes com escabiose em relação à doença, às possibilidades diagnósticas consideradas, à automedicação realizada e os sentimentos diante do conhecimento do diagnóstico. MÉTODOS: Em estudo prospectivo de série de casos, foram entrevistados 65 pacientes com diagnóstico clínico de escabiose atendidos no ambulatório de Dermatologia do Hospital das Clínicas da Universidade Federal de Pernambuco, em Recife, Brasil. RESULTADOS: Apenas 47,7% deles acreditavam que seus sintomas fossem devidos à escabiose, e 86% achavam que esses poderiam ser devidos a outras enfermidades, como infecções, picada de insetos e alergia a contactantes. Como automedicação, observada em 55,4% dos pacientes, os produtos mais utilizados foram os sabões e as plantas. O diagnóstico da escabiose levou a sentimentos negativos em 56,7% dos casos. CONCLUSÕES: O estudo evidenciou ser baixo o grau de suspeição de escabiose entre os infestados. A automedicação foi utilizada em mais da metade dos pacientes, geralmente com produtos inadequados para o tratamento da parasitose. É freqüente o diagnóstico da escabiose levar a sentimentos negativos, indicando a importância da atenção integral ao paciente.

Scabies

Scabies is a neglected parasitic disease that is a major public health problem in many resource-poor regions. It causes substantial morbidity from secondary infections and post-infective complications such as acute post-streptococcal glomerulonephritis. Disease control requires treatment of the affected individual and all people they have been in contact with, but is often hampered by inappropriate or delayed diagnosis, poor treatment compliance, and improper use of topical compounds such as permethrin, lindane, or benzyl benzoate. In addition to concerns over toxicity with such compounds, parasite resistance seems to be increasing. Oral ivermectin is an alternative that has been used successfully in community control programmes. Plant derivatives such as turmeric, neem, and tea tree oil are also promising future treatments. The disease is strongly associated with poverty and overcrowding, and the associated stigma can ostracise affected individuals. Treatment of scabies in poor countries needs to integrate drug treatment programmes with efforts to improve the socioeconomic conditions and education programmes to reduce stigma. We expect the future to bring more sensitive and specific clinical and laboratory-based diagnostic methods, as well as new therapeutic strategies.

Scabies, pediculosis, bedbugs, and stinkbugs: uncommon presentations

Parasitic agents determine some of the most common skin disorders. Although well known, they could present different manifestations or be modified by individual or external factors that make their diagnosis or treatment difficult. This review will discuss some of the most prevalent parasitic infections, scabies, and pediculosis and also mention reactions determined by contact with certain insects that, although rarely found, could induce important skin reactions.

Characterization of an atypical antigen fromSarcoptes scabieicontaining an MADF domain

We have cloned a cDNA encoding a novel antigen from aSarcoptes scabiei(Acari) cDNA library by immunoscreening with sera fromS. scabiei-infected dogs. The antigen is encoded by a 2157 bp mRNA with a predicted open reading frame of 719 amino acids (molecular weight 79 kDa). Our sequence analysis identified the presence of a MADF domain in the N-terminus, and downstream of this domain there was a region of low sequence complexity. This latter region contained several blocks of triplets and quadruplets of polar amino acids (Asn, Gln and Ser), and these 3 amino acids represented 39·7% of all amino acids. The antigen was named Atypical Sarcoptes Antigen 1 (ASA1) since the MADF domain normally is found in proteins involved in transcriptional regulation. In addition, 15 out of 62S. scabiei-infected dogs reacted with a purified recombinant version of ASA1 in Western blot analysis. With immunohistochemistry we could show that ASA1 is expressed throughout the parasite, and that IgG specific for ASA1 binds to the inside wall of the mite's burrow. To our knowledge, this is the first description of an antigen containing an MADF domain.

Ethosuximide and valproate display high efficacy against lindane-induced seizures in mice

Both lindane (gamma-hexachlorocyclohexane), an organochlorine ectoparasiticide and pentylenetetrazol, used as a model of experimental epilepsy, produce convulsive seizures resulting from the blockade of the gamma-aminobutyric acid (GABAA) receptor. In the present study we established the protective effects of ethosuximide and valproate against seizures induced by lindane and compared them with the well-known protective effects of these drugs against pentylenetetrazol-induced seizures in mice. Both ethosuximide and valproate afforded complete and dose-dependent protection against seizures induced by lindane. However, the potencies of these drugs were lower than those obtained against pentylenetetrazol seizures. Nevertheless, the protective efficacy of ethosuximide and valproate against experimentally induced lindane seizures may suggest possible efficacy of these drugs against seizures in lindane-poisoned patients.

Therapy of tungiasis: a double-blinded randomized controlled trial with oral ivermectin

Tungiasis is an ectoparasitosis causing considerable pathology in endemic areas. Standard therapy consists of removing the embedded parasite with a sterile needle. There is no effective chemotherapy at hand. To fill this gap, a double-blinded randomized controlled trial with oral ivermectin was conducted. A total of 54 individuals (27 in the placebo group, 27 in the ivermectin group) was followed up for seven days. They presented a total of 192 lesions. Patients received either ivermectin (300 microg/kg body weight at a single dose, repeated after 24 h) or placebo. Outcome measures included the clinical stage of lesion, presence of erythema, pain, itching, signs of viability of the parasite, and total lysis of flea. The ratio of fleas with total lysis per total number of fleas was slightly higher in the ivermectin group; however, this difference was not statistically significant. There was no significant difference in any of the other outcome measures between the treatment and the placebo group. The results show that oral ivermectin is without any clinically significant efficacy against embedded sand fleas at the dose given.

Controlling scabies in institutional settings: a review of medications, treatment models, and implementation

Scabies is a global problem and a significant source of morbidity in nursing home residents and workers because of its highly contagious nature. It is also a problem in hospitals that care for the elderly, the debilitated, and the immunocompromised. New outbreaks continue to occur, despite controlling the recurrent epidemics. Scabies manifests as papules, pustules, burrows, nodules, and occasionally urticarial papules and plaques. Most of the patients with scabies experience severe pruritus. A subset of patients have crusted or Norwegian scabies. These patients, who are usually debilitated or immunocompromised, do not experience the urge to scratch, and therefore do not scratch their own skin. Diagnosis of scabies is based on patient history, physical examination, and demonstration of mites, eggs, or scybala (black or brown football-shaped masses of feces of scabies) on microscopic examination. Scabies can be treated with topical or oral therapies. Topical treatments include 5% permethrin cream, 1% lindane (gamma benzene hexachloride) lotion, 6% precipitated sulfur in petrolatum, crotamiton, malathion, allethrin spray, and benzyl benzoate. Ivermectin, the only oral treatment, is not approved for scabies in the US. Most authorities advocate using a scabicide several times, specifically once a week over a period of 2-3 weeks. In an outbreak of scabies in a nursing home, residents, staff, and frequent visitors should all be treated even if they are not symptomatic. Ivermectin is useful in treating patients with Norwegian or crusted scabies, or who are debilitated. Ivermectin has no serious reported adverse effects. Model treatment plans to stop scabies epidemics have been developed. These plans coordinate treatment of all persons exposed (including ivermectin for debilitated patients), isolation of infected patients, disinfection of objects that patients have come into contact with, and education and reassurance of the medical staff. Failure to coordinate notification, education, treatment, and disinfection leads to failure to control scabies epidemics. Control of epidemics of institutional scabies requires attention to treatment effects and logistics. Treatment is low risk, but cumbersome because many individuals need be treated. It is advisable to restrict, where possible, the number of staff members that deal with scabies patients to limit the spread of the scabies. Prolonged surveillance is required for the eradication of institutional scabies. While the foregoing plans require coordination of all involved personnel and sustained efforts, they are necessary to halt the spread of scabies to patients and staff, to enhance their morale, and to prevent deterioration of labor and public relations.

Utilisation de 1' ivermectine en médecine tropicale

Ivermectin is a major breakthrough for the treatment of onchocerciasis, strongyloidosis, scabies and cutaneous larva migrans. Combined with albendazole, ivermectin is highly efficient for treating lymphatic filariasis and intestinal worms. Ivermectin shows very few side-effects but its use in children below 5 and during pregnancy is discussed. Ivermectin tolerance could be related to mdr1 gene expression. Additional studies are needed to assess its efficiency for pediculosis.

Cost-benefit analysis of ivermectin, permethrin and benzyl benzoate in the management of infantile and childhood scabies

In the US, 6% sulfur in petrolatum has been the most frequently administered treatment for infantile scabies. It appears to be safe but there is no literature containing a large series of patients on which to base that determination. In the UK, benzyl benzoate is the approved product. Benzyl benzoate is rarely used in the US at the present time. 5% Permethrin is an excellent substitute and has many advantages. It appears to be quite safe in infants, although it is more expensive than other products. It remains present on the skin for several days, therefore protecting against reinfestation. Ivermectin is a systemic drug which is assumed to be safe in infants, although it requires repeated doses and does not protect against reinfestation. In the opinion of the author, 5% permethrin is the best treatment for scabies in infants and young children.