Paediatrics : how to manage scabies

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

Clinical Manifestations of Severe Scabies

Severe scabies, which includes crusted scabies, is an infectious ectoparasitic dermatosis with high mortality and is caused by a florid infestation with sarcoptes scabiei var. hominis. It is usually seen in patients with complex comorbidities, particularly patients with disease-related or iatrogenic dysregulation of cell-mediated immunity as well as those with motor or sensory disturbances of the central or peripheral nervous system. Classic/simple scabies is common worldwide; however, crusted scabies is rare with specific prevalence unknown. Although morphological features are relatively consistent, delayed recognition and implementation of treatment regimens is common, attributable to its infrequent and variable presentation. Complex comorbidities in the patient combined with the significant systemic complications from the disease itself lead to life-threatening disturbances in electrolyte/fluid balance and a high risk of bacterial sepsis due to overwhelming compromise of cutaneous integrity. In addition to the individual risk, severe scabies poses a significant environmental public health risk, with mite numbers in the thousands patients are highly likely to transmit to contacts. Disease recurrence and widespread transmission are common. It is imperative to diagnose and treat severe scabies as one index case can cause an endemic outbreak in communities or institutions

A systematic review of reported cases of pachyonychia congenita tarda

Pachyonychia congenita (PC) describes a group of genodermatoses manifesting as thickened nails, palmoplantar keratoderma (PPK) and increased risk of cutaneous infections. PC tarda (PCT) describes late-onset PC, and associated genetic polymorphisms have been identified. There has been discussion that PCT may not be a distinct entity but rather misdiagnosed ectodermal dysplasia (ED) or PPK. Clarification of this is important for appropriate diagnosis, management and patient and genetic counselling. We aimed to conduct a systematic review of all reported cases of PCT in the published literature and collate evidence of genetic polymorphisms and clinical features to compare with known features of PC, ED and PPK. PubMed (1946 to 1 July 2018), Scopus (1955 to 1 July 2018) and Web of Science (1990 to 1 July 2018) databases were searched for case reports of PCT with no search restrictions on date or language. The search strategy included the terms pachyonychia congenita tarda OR pachyonychia congenita AND (late onset OR delayed OR PCT). In total, 13 reports describing 19 individual cases of PCT were identified. Of the three identified genetic polymorphisms, the earliest identified has been shown to be highly probably pathogenic, with the second likely to result in a benign amino acid change, while the third has since been shown to be nonpathogenic,. No epigenetic studies have been performed on any reported cases. Previous authors have suggested that a number of cases of PCT may be misdiagnosed ED or PPK. The findings of our review cannot refute this suggestion, and highlight the need for thorough clinical documentation of suspected cases of PCT and thorough genetic screening of kindred to identify causative genetic polymorphisms. Further high-quality datasets and reporting are needed to give further insight into the nature of PCT as a unique entity

A retrospective cohort study of melanoma prevalence stratified by body site in a Regional Australian Population 1994-2017: Site-specific protective mechanisms

Background: Australia has the highest incidence of cutaneous melanoma worldwide. Previous studies have identified some body areas (forearms and dorsal hands) have lower rates of melanoma than expected when compared with other similarly exposed areas, leading to the suggestion that endogenous immunological protective mechanisms in certain body sites may exist. Aims and Methods: We hypothesise that examination of melanoma by body site in a regional Australian setting would demonstrate no significant variation in the incidence of melanoma across highly sun exposed areas including the head and neck and upper limbs. Results were stratified by body site and further examined by univariate correlation analysis by gender, age, body site, Breslow thickness and subtype. Polytomous logistic regression was used to test the difference in risk factors by location of melanoma. Results: A total of 772 melanomas were included in the analysis. Melanomas of the upper limb were more likely to affect females (OR = 2.415 95%CI: 1.433-4.072) and more likely to be thinner than other body sites. Compared to other international studies, statistically significant decreased rates of melanoma were seen on the upper limb compared to other areas of the body (X 2  = 16.29, P < 0.001). Examination of sites of melanoma on the upper limb showed significantly decreased rate on the distal upper limb given relative body surface areas (X 2  = 6.30 P = 0.04). Discussion and Conclusions: Our study was limited by its retrospective nature, and the findings require validation in a larger prospective cohort. Further exploration of such mechanisms may lead to new insights into the immunological mechanisms surrounding cutaneous melanoma

Secondary Syphilis with Eosinophilia Complicated by Severe Jarisch–Herxheimer Reaction

It has long been acknowledged that syphilis is a disease with a diverse range of presentations. We herein describe a case of a young man who presented with fever, rash, and eosinophilia following the commencement of allopurinol, only to be diagnosed with secondary syphilis on histopathology. His treatment was complicated by a severe exacerbation of his cutaneous eruption following the commencement of penicillin, likely secondary to a Jarisch–Herxheimer reaction, an entity often overlooked by clinicians managing syphilis

Cutaneous malignancies in Indigenous peoples of urban Sydney

Introduction: Despite 3% of Australians identifying as Indigenous, cutaneous malignancies in these patients, including incidence, risk factors and outcomes have not been investigated. This is despite recognition that cancer outcomes in this population are significantly poorer. Methods: We undertook a retrospective case series of Indigenous Peoples who presented to two urban cancer therapy centres for the management of cutaneous malignancies from 2003 to 2017. Risk factors, tumour‐specific characteristics, treatments and outcomes were reviewed. Results: Twenty‐two patients identified as Aboriginal and/or Torres Strait Islander. The median age at presentation was 61 years and the majority were male (63.6%) and had skin phototype III (86.4%). Patients presented with basal cell carcinoma (50%), squamous cell carcinoma (31.8%), melanoma (9.1%) and cutaneous sarcomas (9.1%). The majority (68.2%) presented with stage II or higher disease, and there were high rates of immunosuppression (45.5%). At the time of reporting, 68.2% patients were alive, 18.2% had died from their skin cancers and 13.6% had died from unrelated causes. Conclusion: This cohort has demonstrated late‐stage presentation of skin cancers, with substantial morbidity and mortality from potentially treatable cutaneous malignancies. This parallels other health conditions in Indigenous Australians and has highlighted the need for improved data collection of Indigenous status to better quantify the epidemiology of skin cancer in this population. There is an imperative to improve skin cancer awareness in this population to allow earlier detection and management to ensure better outcomes