Paediatrics: how to manage scabies

Escalating Threat of Drug-Resistant Human Scabies: Current Insights and Future Directions

Background: Scabies is a prevalent dermatological condition with significant public health implications. The recent rise in drug-resistant scabies presents new challenges for effective disease management and control. Methods: A comprehensive literature review was conducted using PubMed, Cochrane Library, and Web of Science. Studies published from 2000 to August 2024 were considered, focusing on those reporting drug-resistant scabies and advancements in treatment approaches. Results: Clinical studies, in vitro investigations, and case reports show significant resistance of human scabies to permethrin. Main resistance mechanisms involve genetic mutations in the mites' voltage-gated sodium channels (VGSCs) and enhanced activity or expression of the detoxifying enzyme glutathione S-transferase (GST). Resistance to ivermectin and benzyle benzoate, although suggested by some authors, seems less obvious. The clinical evidence of widespread ivermectin resistance in human scabies infestations is lacking, despite indications of increased tolerance in laboratory settings and anecdotal reports of resistance in patients with crusted scabies. Benzyl benzoate resistance in scabies mites remains unconfirmed. Conclusions: Permethrin-resistant scabies is an escalating threat requiring new management strategies and updated guidelines. Infection control measures, alternative treatments, and ongoing research into new therapeutics are crucial to mitigate the impact of drug-resistant scabies.

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.

The current available diagnostic tools and treatments of scabies and scabies variants: An updated narrative review

Scabies is a neglected tropical disease that continues to have global impacts and long-term health consequences. It is caused by the mite Sarcoptes scabei var. hominis, which is an obligate ectoparasite that lives in the epidermis of the human skin. Scabies is common in poor communities due to overcrowding in places like old age homes, prisons, and homeless and displaced children. However, developed countries are also susceptible to scabies infestations, such as in institutional outbreaks or small epidemics under war conditions or during natural disasters. The diagnosis of scabies may be assisted by invasive and noninvasive tools; However, the history and examination findings are usually adequate to confirm the clinical suspicion. Here, we present an updated review of scabies by focusing on the diagnostic approaches, treatment, and prevention of scabies.

Bugs, Bumps, and Bacteria: The Role of Virtual Collaborative Learning Network in Pediatric Dermatology

Patients in rural and underserved areas face significant barriers in accessing specialty care due to unavailability of services, geographic isolation, travel burden, and other cultural and socioeconomic factors.1 Pediatric dermatology is among the top three subspecialties that provides routine care for pediatric patients, however, shortage and maldistribution of pediatric dermatologists have remained a major hurdle for those living in remote and isolated areas.2 Pediatric dermatologists cluster in urban areas with high-patient volume and estimated wait times for new patients that often exceed 13 weeks, making access one of the major drivers of inequity for rural patients.2-4.

Disseminated scabies in a 2-month-old infant

Scabies is a skin disease caused by the mite Sarcoptes scabiei. We report disseminated scabies in a 2-month-old girl as well as eczematoid lesions in her mother. The diagnosis was made by skin scraping and microscopic examination of the crusts. The patients were successfully treated with permethrin cream (5%).

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.

MRSA Femoral Osteomyelitis from Superinfected Scabies Lesions: A Pediatric Case Report

Scabies is a skin infestation from the Sarcoptes scabiei. It is considered a public health issue causing concern in developing countries and is considered a “neglected tropical disease” by the World Health Organization (WHO). Scabies skin lesions may cause severe itching and can be the portal of entry for opportunistic and pathogenic bacteria, which can cause serious systemic infections. We report the case of a 3-year-old boy with recurrent scabies infections who presented to the emergency department because of a fever and refusal to walk. Blood tests showed neutrophilic leukocytosis and significantly increased C reactive protein (CRP) and procalcitonin. Upon medical examination, his right thigh was extremely painful upon palpation, knee flexion was lost and he was unable to stand, so magnetic resonance imaging (MRI) was performed. MRI showed osteomyelitis of metaphysis and distal diaphysis of the right femur with associated subperiosteal purulent collection and concomitant pyomyositis and fasciitis of the distal right thigh. Blood cultures were positive for methicillin-resistant Staphylococcus aureus (MRSA). The patient received a long course of intravenous antibiotic therapy and his condition slowly improved. Follow-up femur X-ray showed a mixed pattern of erosion and sclerosis at the meta-diaphyseal region and periosteal reaction at the diaphyseal region. This case highlights the importance of early scabies diagnosis even in Western countries where poverty and household overcrowding are uncommon. Early diagnosis, timely initiation of proper treatment and evidence of clinical resolution are important elements to prevent recurrence of infection and serious systemic superinfections even from multi-drug resistant bacteria. Clinical consequences from unrecognized disease or inadequate eradication are preventable.