Clinical phenotype of scabies by age

Scabies

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

Scabies, Bedbug, and Body Lice Infestations: A Review

Importance

Scabies, bedbug, and body lice infestations are caused by organisms that live on or in the skin, on clothing, or in the environment and commonly cause pruritus and rash. In 2021, approximately 622 million incident cases of scabies occurred globally. Data on bedbug infestations are limited. Body lice prevalence ranges from 4.1% to 35% among persons experiencing homelessness worldwide.

Observations

Scabies is caused by mites (Sarcoptes scabiei) that burrow into the epidermis. Transmission primarily occurs from prolonged skin-to-skin contact with an individual who has an infestation. Common scabies is characterized by excoriated pruritic papules, plaques, and pathognomonic burrows on finger/toe web spaces, volar wrists, ankles, axillae, buttocks, male genitalia, and areolae. Permethrin cream and oral ivermectin are first-line treatments for adults, with similar clearance rates by week 2 (74% with permethrin vs 68% with ivermectin; relative risk, 0.91; 95% CI, 0.76-1.08). Treatment failure can occur with oral ivermectin (11.8%; 95% CI, 8.4%-15.4%) and topical permethrin (10.8%; 95% CI, 7.5%-14.5%). Bedbugs (Cimex lectularius, Cimex hemipterus) are insects that live on mattresses and furniture and feed on blood nocturnally, causing linear pruritic erythematous papules. New skin lesions on waking, cohabitants with similar symptoms, and recently residing in a high-occupancy setting should raise suspicion. Treatment requires eradication with pest management. Body lice (Pediculus humanus humanus) are insects found on clothing that travel to the skin for blood meals. Body lice bites cause pruritic excoriated macules/papules and hyperpigmentation in areas where clothing seams contact skin. Treatment and prevention require at least once-weekly bathing and laundering of clothing and bedding.

Conclusions and Relevance

Scabies, bedbug, and body lice infestations are common. Accurate diagnosis requires taking a history, including social drivers of health (eg, housing status, living environment), and physical examination. First-line treatments include scabicides for patients with common scabies and their close contacts. Scabies, bedbug, and body lice infestations should be treated with decontamination measures.

Scabies in infants and children - a narrative review

Scabies is a human ectoparasitosis caused by Sarcoptes scabei var. hominis. World-wide around 300 million patients are affected. Infants and children have the highest incidence rates. Poverty and overcrowding are social factors contributing to a higher risk of transmission and treatment failure. The leading symptom of the infestation is itch. Complications are bacterial infections that are responsible for mortality. Diagnosis is clinical. Non-invasive imaging technologies like dermoscopy can be used. Polymerase chain reaction (PCR) is less sensitive and specific than microscopy of skin scrapings. Treatment of choice is topical permethrin 5%. Ivermectin is the only oral drug FDA-approved for scabies. It should be used in cases non-responsive to topical therapy and in case of high number of infested patients in addition to topical therapy. Pseudo-resistance to treatment is not uncommon. New drugs are on the horizon. What is Known: • Pruritus is the leading symptom causing sleep disturbances and scratching with the risk of secondary bacterial infections. • Treatment failure is related to inappropriate application of topical drugs and asymptomatic family members. What is New: • COVID-19 pandemic and migration are contributing to an increased incidence of scabies. • New compounds to treat scabies are on the horizon.

Scabies in Infants: Series of 51 Cases

We conducted a two-year retrospective evaluation of infants aged under two years with a confirmed, clinical, or suspected diagnosis of scabies in a healthcare center in Alicante (Spain) to determine possible factors associated with diagnostic delay and poor treatment response. We collected epidemiological, clinical, diagnostic, and treatment variables. After describing our findings as mean values and percentages, we compared categorical variables using the Student's t-test and the Mann-Whitney U test, and we compared continuous variables with the Chi2 test and Pearson's correlation coefficient. We included 51 infants (19 boys and 32 girls) with a mean age of 15 months. The main source of contagion was the family; half of the infants lived with four or more people. According to the International Consensus Criteria for the Diagnosis of Scabies, confirmed scabies was diagnosed in 45% of cases and clinical scabies in 47%, and 45% of cases had a diagnostic delay. Lesions mainly affected the hands, feet, and trunk, with papules in 92% of cases and burrows in 55%. The predominant symptoms were pruritus (94%) and irritability (69%). Regarding treatment, 98% of the infants received topical permethrin and 35% received oral ivermectin. Treatment failed in 76% of infants. Living in large family units was associated with a higher risk of contagion and therapeutic failure. Diagnostic delay was associated with previous misdiagnosis.

Scabies: Immunopathogenesis and pathological changes

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

National survey in Switzerland calls for improved diagnosis and treatment in children with scabies

AIM OF THE STUDY

The global prevalence of scabies is estimated to be up to 200 million cases annually, with young children particularly affected. In Europe, most cases are thought to originate in migrant populations. Scabies management is challenging in children. To identify knowledge gaps and research needs, we aimed to descriptively evaluate the management of children with scabies by different Swiss healthcare providers.

METHODS

An invitation for an anonymous online survey (36 questions) was sent to members of Swiss societies of dermatologists, general practitioners, paediatricians, paediatric dermatologists, paediatric infectious diseases specialists, and tropical medicine specialists, inviting clinicians to participate from 25th May to 8th August 2020. One reminder invitation was sent. Hospital pharmacies and the distributor of permethrin were contacted to report consumption trends of scabicides in 2018 and 2019.

RESULTS

The survey was completed by 248 clinicians: 146 (59%) paediatricians, 47 (19%) dermatologists, 28 (11%) general practitioners, 6 (2%) paediatric dermatologists, 13 (5%) paediatric infectious diseases specialists, and 8 (3%) tropical medicine specialists. Most consulted up to 10 scabies cases within a 16-month period, with similar numbers in migrant and Swiss children. Dermoscopy was used by 24% of non-dermatologists. Non-dermatologists did not consider co-treatment of close contacts in up to 59% of cases. While permethrin was the first-line treatment, treatment failures were frequently reported in children aged <5 years. Up to 67% of paediatric dermatologists regularly used oral ivermectin off-label in children weighing <15 kg. None of the paediatric dermatologists, 15% of the dermatologists, and 9% of the non-dermatologists used only one treatment cycle.Scabicide consumption increased. Treatment studies on ivermectin use in children weighing <15 kg had the highest research priority.

CONCLUSION

In Switzerland, scabies is a frequent dermatosis in migrant and Swiss children. While accessible, optimal diagnostics are underutilised, and treatment is suboptimal. Permethrin resistance appears to be an increasing problem. Dermatologists regularly use ivermectin off-label in children weighing <15 kg. Treatment studies on ivermectin use in children weighing <15 kg, user-friendly diagnostic tools, new treatment protocols, and child-friendly dosage forms are needed to improve the diagnosis and treatment of children with scabies.

Neonatal Norwegian scabies

Norwegian scabies is a severe form of scabies usually seen in immunocompromised children and adults. It is rarely reported in the neonatal age group. We present such a case.

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.

Crusted scabies in children in France: a series of 20 cases

To evaluate the risk factors for crusted scabies in children in France. The retrospective multicenter study, conducted in France, of children (aged < 18 years) with profuse and/or crusted scabies confirmed by dermoscopy and/or microscopy. Data were obtained using a standardized questionnaire. We included 20 children. The mean age was 4.5 years, and 70% of the patients were girls. Their medical history revealed a neurological pathology (agenesis of the corpus callosum; n = 1, 5.0%), prematurity (n = 1, 5.0%), Down syndrome (n = 1, 5.0%), atopic dermatitis (n = 2, 10%), and asthma (n = 2, 10.0%). Fifteen (75.0%) children were treated with steroids before being diagnosed with scabies: 12 (60.0%) with topical steroids, one (5.0%) with a systemic steroid, and two (10.0%) with inhaled steroids. One child (5.0%) lived in a precarious environment. The mean duration of pruritus was 3.4 months, and that of the skin lesions was 3.1 months. The most commonly affected areas for crusted scabies were the palms/hands (66.7%) and the armpits (33.3%). Thirteen children (65.0%) were hospitalized, 14 (70.0%) were treated with ivermectin and all received topical treatments; 85.7% were cured within an average of 38 days, but one child had a relapse 3 months later in the form of common scabies.Conclusion: The main risk factor for developing crusted scabies in France was the misdiagnosis and the use of corticosteroids, especially topical forms typically used in "healthy" children. Management of the children was effective and similar to that used in adults. What is Known: • Crusted scabies is an extremely contagious disease which is rarely reported in infancy, especially in healthy children. • The main risk factors include immunosuppression, physical debilitation, and intellectual disability. What is New: • The main risk factor of severe scabies in this study was delayed diagnosis associated with the use of topical or systemic corticosteroids. • The treatment was successful in 85.7% of cases, and 65% of children needed to be hospitalized.

Scabies: Epidemiology, Diagnosis, and Treatment

BACKGROUND

Scabies is a skin infestation whose incidence is apparently rising.

METHODS

This review is based on pertinent articles retrieved by a selective search of PubMed on diagnosis and treatment strategies.

RESULTS

Thread-like papules (burrows), new, intense pruritus, and dermatitis guide the suspected diagnosis which is confirmed by the microscopic or dermatoscopic demonstration of scabies mites. The first line therapy is topical application of permethrin, in accordance with the current recommendations for its use. Other treatment options include systemic ivermectin and topical crotamiton or benzyl benzoate. A combination of permethrin and ivermectin is used to treat otherwise intractable cases and is generally indicated for the treatment of crusted scabies. Known causes of treatment failure include improper application of the external agents, failure of repeated treatment with ivermectin, incomplete decontamination of furnishings and clothes, failure to simultaneously treat contact persons, absence of written documents explaining treatment modalities, and the patient's belonging to a risk group. Even though there has not yet been any direct proof of resistance of scabies mites to permethrin, there is a rising number of welldocumented cases of poor response to this agent. Moxidectin is a new substance now undergoing clinical testing.

CONCLUSION

Treatment of scabies according to the guidelines and the additional recommendations reported here should result in effective curing, even in cases that are thought to be intractable.

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.

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.

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.

Itch in Scabies-What Do We Know?

Scabies is a common parasitic skin infestation characterized by severe itch and a heterogenous clinical presentation. Itch, as the cardinal symptom of scabies, is imposing a high burden on affected patients and is often difficult to manage. Decreased life quality and secondary complications, caused by an itch-related disruption of the epidermal barrier and subsequent superinfections, illustrate the need to treat scabies and to understand the underlying mechanisms of itch in respective patients. This review summarizes available data on itch in scabies with a special focus on the clinical aspects and its underlying pathomechanisms.

Prevalence of scratching during examination among patients with scabies and among patients with other pruritic dermatoses

BACKGROUND

Scabies is a parasitic skin disease. Its clinical diagnosis may be challenging.

METHODS

In a prospective observational study, we enrolled all consecutive patients ≥16 years of age with a presumptive diagnosis of scabies and all patients ≥16 years of age with a diffuse itchy dermatosis lasting for more than 1 week. We investigated whether patients with scabies were more prone to scratch themselves during the consultation than patients with other pruritic dermatoses.

RESULTS

We observed that a significant proportion of patients (25/62, 40%) with scabies had to scratch while talking or being examined. This clinical sign was less frequently noticed in patients with pruritic dermatoses of other origins (26/196, 13%) (P < 0.001).

CONCLUSIONS

The observation of a patient scratching himself during the consultation should prompt serious consideration of scabies. This easily observable clinical sign may be especially useful in low-resource settings, where scabies is known to be very prevalent.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A comparative study of topical tacrolimus and topical triamcinolone acetonide in nodular scabies

The aim of this study was to compare the efficacy and safety of 0.1% triamcinolone acetonide and 0.03% tacrolimus ointment for the treatment of nodular lesions of scabies. In this double-blind randomized controlled trial, 50 Indian men with postscabeitic persistent nodular lesions (labelled to have nodular scabies (NS)/postscabies prurigo (PSP)) over the external genitalia, were enrolled. They were randomized into two groups to receive either a mid-potency topical corticosteroid (TCS); triamcinolone acetonide 0.1% ointment twice daily, or topical calcineurin inhibitor (CNI); tacrolimus ointment 0.03% twice daily over the nodular lesions for 2 weeks. All patients were followed up on three visits: 1, 2, and 6 weeks, for assessment. Efficacy was evaluated by 5-point range investigator-assessed VAS, and a 4-point severity of pruritus scale (SPS) score. The mean VAS score was higher in triamcinolone group compared to tacrolimus group at both follow-ups, although statistically significant only at 2nd week visit. The fall in mean SPS at both follow-ups was also higher in the steroid group, but the difference was not statistically significant. While, the overall tolerance to either ointment was excellent, mild hypopigmentation, and epidermal atrophy were detected on dermoscopic evaluation of the treated areas at the 2nd week visit in a small subset of patients in the triamcinolone group. The frequency of relapse of lesions and/or pruritus after four weeks of the 2-week therapy was high in both the groups (higher in tarolimus group). Conclusively, although both treatment options provided safe and satisfactory short term improvement, the results from this study suggest an overall higher efficacy of a mid-potency TCS like triamcinolone 0.1% over topical CNI like tacrolimus 0.03%, in the short-term treatment of nodular lesions of NS/PSP. Topical CNIs may be considered for maintenance of effect, if prolonged therapy is warranted.

Scabies: A comprehensive review and current perspectives

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

[Increase of scabies and therapy resistance among German military personnel : An 8-year follow-up study in the Department of Dermatology of the Armed Forces Hospital Berlin, Germany (2012-2019)]

BACKGROUND

The diagnosis of scabies has become surprisingly frequent in Germany in recent years and the use of scabicides has risen significantly.

OBJECTIVE

The aim of our survey was to determine whether this trend can also be detected among military personnel of the German Armed Forces (Bundeswehr).

METHODS

The study was conducted as a retrospective single-center study over a period of 8 years from 2012 to 2019 in the Department of Dermatology of the Armed Forces Hospital Berlin, Germany. Data were generated from the hospital information system (KIS), which was searched for all scabies-coded diagnoses according to ICD10 code B86 both as outpatients and inpatients. Only first presentations with scabies diagnosis confirmed by dermoscopy or microscopy by a dermatologist were included. Inpatient treatment was required if a patient was not cured after at least three antiscabies treatment cycles in the outpatient setting.

RESULTS

The data show that there has been a steady increase in the diagnosis of scabies in Bundeswehr personnel. Moreover, our data show that the number of unsuccessfully treated outpatients increased and required in-hospital treatment.

CONCLUSION

We observed an increase of scabies among German military personnel who represent a typical at-risk group. These results support the observations of an increased incidence of scabies in Germany in general and especially in an at-risk population. With the general increase in scabies cases, there are also increasing numbers of German military personnel who are refractory to treatment, which was largely attributed to inadequate treatment of contact persons and individual treatment errors. Nevertheless, the data also emphasize the low overall prevalence of scabies; therefore, all diagnoses should be confirmed by dermoscopy or microscopy after 14 days whenever possible to rule out the bias of overreporting due to false-positive cases diagnosed only by clinical examination.

Infestations, Bites, and Insect Repellents

Infestations and arthropod bite reactions in children are common reasons for presentation to pediatric health care providers. Infestations in children include head lice, scabies, and other mites. Fleas and bed bugs are common causes of bite reactions in children, and papular urticaria is a chronic, recurrent eruption resulting from delayed hypersensitivity to a variety of insect bites. Both infestations and bite reactions may result in severe pruritus with associated sleep disturbance and can be a source of significant distress for patients and families. In this review, we discuss infestations and bite reactions affecting pediatric patients, along with the approach to treatment and prevention of these conditions. [Pediatr Ann. 2020;49(3):e124-e131.].

Prevalence of scabies and impetigo in the Solomon Islands: a school survey

BACKGROUND

Scabies, a parasitic disease of the skin, is a major public health problem, largely affecting children. Scabies is often complicated by impetigo which can result in serious complications including invasive infections and immune mediated diseases. Scabies and impetigo are reported to have high prevalence in tropical settings including the Solomon Islands.

METHODS

We conducted a cross-sectional prevalence survey at Gizo Primary School in the Western Province of the Solomon Islands in August 2018. The diagnosis of scabies was based on criteria developed by the International Alliance for the Control of Scabies in 2018. Population attributable risk was calculated to determine the effect of scabies on the prevalence of impetigo, and both adjusted and unadjusted risk ratios were calculated to identify differences between sexes and age groups.

RESULTS

A total of 324 students were assessed (47.5% of those enrolled at the school). The prevalence of scabies was 54.3% (95% confidence interval [CI] 48.7-59.8) and most disease was mild (68.8%). The prevalence was higher in males (63.5%; adjusted risk ratio [ARR] 1.4, 95% CI 1.1-1.7), and in those aged 10-12 years (61.4%; ARR 1.8, 95% CI 1.1-2.9 when compared to those aged 4-6 years). The prevalence of impetigo was 32.1%, with males more likely to be affected (41.7%, ARR 1.7, 95% CI 1.2-2.4) but with no significant differences between age groups. 63.5% of those with impetigo had scabies, corresponding to a population attributable risk of 11.8%.

CONCLUSIONS

There is a very high burden of scabies and impetigo among primary school students in Gizo. There is a critical need for the development and implementation of control programs in areas where scabies is endemic.

The diagnosis of scabies by non-expert examiners: A study of diagnostic accuracy

Background

Although scabies is estimated to be one of the most common skin conditions globally, prevalence data is not available in most settings. Disease mapping is required to develop and monitor successful control programs. Non-expert health workers are likely to play an important role in scabies mapping activities in endemic settings.

Methodology

Four non-expert health workers were trained in the diagnosis of scabies and impetigo. The health worker diagnosis was compared to a reference consensus diagnosis of two doctors experienced in diagnosis. The study was conducted in a primary school in Gizo, Solomon Islands, in August 2018. The six examiners consecutively assessed school students, blinded to each other’s findings. Training and diagnostic procedures followed criteria for scabies diagnosis established by the International Alliance for the Control of Scabies in 2018.

Principal findings

Amongst the 171 students who underwent clinical assessment the prevalence of scabies and impetigo according to the reference standard was 55% and 45% respectively. Sensitivity of the non-expert health workers’ diagnosis compared to the reference standard was 55.3% for scabies (95% confidence interval [CI], 50.1–60.4) with a specificity of 89.9% (95% CI 86–93.1) and 52.6% for impetigo (95% CI 46.9–58.3) with a specificity 97.8% (95% CI 95.7–99). Sensitivity for moderate to severe scabies was 93.5% (95% CI 86.3–97.6) with a specificity of 74% (95% CI 70.2–77.5).

Conclusions

Following brief training, the diagnostic accuracy of non-expert health workers for scabies and impetigo was promising, especially for moderate to severe disease. Modifications to training and processes are recommended to further improve accuracy. The diagnosis by non-expert health workers may be acceptable for scabies and impetigo mapping in endemic areas.

Scabies is a parasitic infection that leads to significant morbidity worldwide. Mapping of scabies prevalence would improve the understanding of the true burden of disease and the need for control programs in specific countries and regions. The diagnosis of scabies in low resource settings, where the disease is most prevalent, is reliant on clinical examination. A task shifting approach, utilizing local health staff, could substantially increase the feasibility to undertake mapping surveys in low-resource settings. In this study, we aimed to evaluate the diagnostic accuracy of clinical assessment of local health workers following brief training. Our study found that these non-expert health workers could diagnose scabies with moderate accuracy and diagnose more severe disease with high accuracy. Further work is needed to develop standardized training packages to ensure a high level of diagnostic accuracy by non-expert health workers.

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.

Increase of scabies in Germany and development of resistant mites? Evidence and consequences

Scabies has been diagnosed surprisingly frequently in Germany in recent years, and the use of acaricides has risen markedly. Present figures indicate an increase in the prevalence/incidence of scabies, but do not prove or quantify it for the following reasons: (a) scabies is not a notifiable disease in Germany; (b) the diagnosis is not always confirmed lege artis by means of light microscopy or dermatoscopy (which may lead to a comparatively high proportion of false‐positive diagnoses due to the low overall prevalence of scabies); (c) repeated treatments of the same patient and treatment of contact persons are included in the total number of prescriptions. Therefore, there are no valid data on disease occurrence, either in the current situation or from previous periods. Observations of ineffective treatment with permethrin have led to speculations that Sarcoptes mites are developing resistance to this drug. However, there is little evidence for this assumption. We discuss risk groups (children, elderly people in need of care, migrant health personnel in nursing institutions, refugees, sexually active young adults) and evaluate their possible contribution, albeit in the absence of evidence. None of the groups would be solely responsible for an increased frequency. We have compiled recommendations on how the management of scabies could be improved, and present a way of differentiating permethrin resistance from application errors and/or lack of compliance. The goal is to solve the epidemiological and parasitological questions mentioned above.

Insight into scabies

Scabies, an infectious disease caused by the scabies mite, manifests as an intensely pruritic skin rash. Children, the underprivileged, and patients with immunocompromise are at a higher risk of acquiring this contagious disease. Infectivity occurs worldwide in patients of all races, ages, and sex. The classical appearance of papular burrows between the webbed spaces of digits or along the wrists can help distinguish scabies from other dermatologic diseases. Practitioners need to be familiar with how scabies may present so that patients can be treated and taught how to prevent spread of the disease.

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

Background

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

Methods

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

Findings

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

Interpretation

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

Funding

Public Health England and British Skin Foundation.

Prevalence of Nail Scabies: A French Prospective Multicenter Study

INTRODUCTION

To assess the prevalence of nail involvement in children <16 years old with a confirmed diagnosis of scabies.

STUDY DESIGN

Observational, prospective study in 7 French dermatology departments between June 2015 and January 2017. Children were included if they had scabies confirmed by dermoscopy and/or microscopy and if nails could be sampled. The first toenails and thumbnails as well as clinically affected nails were systematically sampled for microscopic examination. Individual data were recorded via a standardized questionnaire.

RESULTS

A total of 47 children with scabies were included (26 females [55.3%], mean age 3.6 ± 4.0 years). Pruritus was present in 42 children (89.3%); the relapse rate was 38.3% (n = 18). In 3 infants (6.4%), Sarcoptes mites were revealed by dermoscopy or microscopy of the first toenails (2 cases) and a thumbnail (1 case), but nails were normal in 2 children. Two of the 3 infants had already received treatment for scabies in the previous weeks.

CONCLUSION

Prevalence of nail involvement in children with confirmed scabies was 6.4%. Nails should not be overlooked during scabies treatment.

Scabies in babies

The clinical manifestations of scabies infestation vary according to age, making the diagnosis challenging, particularly for primary care providers and dermatologists who do not routinely care for young children. We present seven cases of newborns and infants who developed inflammatory burrows and nodules early in the course, which is not typical of the eruption seen in older children and adults. We review the cutaneous features, differential diagnosis, and treatment recommendations for scabies in different age groups.

Case Report: Bullous Scabies in Two Children below 10 Years

Bullous scabies is an infrequent and atypical presentation of scabies, with predilection for elderly and males. Its median age of presentation is 70 years. We report two male cases of bullous scabies who were 7 years and 6 months old. Both patients had excellent response to sulfur 10% ointment alone and have had no recurrence in more than 3 months of follow-up.

Infections and skin diseases mimicking diaper dermatitis

Diaper dermatitis is a common condition that often prompts parents to seek medical attention. Irritant diaper dermatitis is by far the most common cause, but numerous potentially serious diseases can present with changes of the skin in the diaper area. The differential diagnosis can include psoriasis, metabolic disorders, rare immune diseases and infection. Clinical examination can be helpful in distinguishing the underlying cause. General screening laboratory tests, as well as select testing when a specific condition is suspected, can be used to challenge or confirm the putative diagnosis.

[Scabies of the nail unit in an infant]

BACKGROUND

There are no guidelines regarding the management of scabies in infants and recurrence is common at this age. We report the case of an infant with subungual hyperkeratosis and ungual lesions subsequent to classic scabies.

PATIENTS AND METHODS

A 7-month-girl, treated 6 weeks earlier with esdepallethrin for scabies, consulted for acquired lesions on 3 toe nails. These nails were thickened and displayed subungual hyperkeratosis. Physical examination of the skin, the finger nails and mucous membranes was otherwise normal. Fungal analyses were negative, but direct microscopic examination revealed numerous larvae of Sarcoptes scabiei as well as ovular debris. The child was treated with urea 40% to obtain chemical avulsion of the nails, and with topical esdepallethrin and a quarter tablet of ivermectin orally; there was no follow-up of the child.

DISCUSSION

Ungual scabies has already been reported in crusted scabies and very rarely in classic scabies. Subungual and ungual locations of S. scabiei may constitute a source of reinfestation with scabies in infants. Treatment is not well defined and currently involves chemical avulsion of the nails and the application of topical antiscabies treatment.