Scabies and pyodermas--diagnosis and treatment

Optimal Control and Cost-Effective Analysis of a Scabies Model with Direct and Indirect Transmissions

Scabies is caused by sarcoptes scabiei var. hominis, which is also referred to as itch mice. The disease is transmitted through direct contact with an infected person, or from contact with infested bedding or clothing. In this paper, a mathematical model for the spread of scabies was proposed and analyzed. Sensitivity analysis of the model parameters was carried out. Optimal control theory was applied to our proposed model, with the controls representing treatment and vaccination. Our aim was to minimize cumulative infectious cases and susceptible individuals through treatment and vaccination, respectively. Pontryagin’s maximum principle was utilized to characterize the optimal levels of the two controls. The resulting optimality system was then solved numerically. The optimal control result was further highlighted by applying the results realized from the cost objective functional, the IAR, and the ICER.

Treatment of scabies using a tea tree oil-based gel formulation in Australian Aboriginal children: protocol for a randomised controlled trial

INTRODUCTION

In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their first birthday. This is more than six times the rate seen in the rest of the developed world. Scabies infestation is frequently complicated by bacterial infection, leading to the development of skin sores and other more serious consequences, such as septicaemia and chronic heart and kidney diseases. Tea tree oil (TTO) has been used as an antimicrobial agent for several decades with proven clinical efficacy. Preclinical investigations have demonstrated superior scabicidal properties of TTO compared with widely used scabicidal agents, such as permethrin 5% cream and ivermectin. However, current data are insufficient to warrant a broad recommendation for its use for the management of scabies because previous studies were small or limited to in vitro observations.

METHODS AND ANALYSIS

A pragmatic first trial will examine the clinical efficacy of a simple and low-cost TTO treatment against paediatric scabies and the prevention of associated secondary bacterial infections, with 1:1 randomisation of 200 participants (Aboriginal children, aged 5-16 years and living in remote Australia) into active control (permethrin 5% cream) and treatment (5% TTO gel) groups. The primary outcome for the study is clinical cure (complete resolution). Secondary outcome measures will include relief of symptoms, recurrence rate, adverse effects, adherence to treatment regimen and patient acceptability.

ETHICS AND DISSEMINATION

The project has received approvals from the University of Canberra Human Research Ethics Committee (HREC 16-133), Wurli-Wurlinjang Health Service Indigenous subcommittee and the Aboriginal Medical Services Alliance Northern Territory reference group. The results of this study will be published in core scientific publications, with extensive knowledge exchange activities with non-academic audiences throughout the duration of the project.

TRIAL REGISTRATION

ACTRN12617000902392; Pre-results.

Therapeutic Potential of Tea Tree Oil for Scabies

Globally, scabies affects more than 130 million people at any time. In the developed world, outbreaks in health institutions and vulnerable communities result in a significant economic burden. A review of the literature demonstrates the emergence of resistance toward classical scabicidal treatments and the lack of effectiveness of currently available scabicides in reducing the inflammatory skin reactions and pyodermal progression that occurs in predisposed patient cohorts. Tea tree oil (TTO) has demonstrated promising acaricidal effects against scabies mites in vitro and has also been successfully used as an adjuvant topical medication for the treatment of crusted scabies, including cases that did not respond to standard treatments. Emerging acaricide resistance threatens the future usefulness of currently used gold standard treatments (oral ivermectin and topical permethrin) for scabies. The imminent development of new chemical entities is doubtful. The cumulative acaricidal, antibacterial, antipruritic, anti-inflammatory, and wound healing effects of TTO may have the potential to successfully reduce the burden of scabies infection and the associated bacterial complications. This review summarizes current knowledge on the use of TTO for the treatment of scabies. On the strength of existing data for TTO, larger scale, randomized controlled clinical trials are warranted.

Common skin problems in children

Childhood dermatological problems contribute about one-third of all consultations in the setting of both pediatrics and dermatology outpatient services. Skin disorders in children may cause anxiety to parents. General Practitioners should be familiar with the common prevalent skin problems as immediate pediatric dermatology consultation may not be possible. Infections, infestations and dermatitis are the most prevalent diseases among Indian children. The scope of this review is to briefly highlight these common and other important dermatological problems in children.

Skin disorders among travellers returning from tropical and non-tropical countries consulting a travel medicine clinic

OBJECTIVE

To evaluate the causes and risks for imported skin disorders among travellers.

METHODS

Data of 34,162 travellers returning from tropical and non-tropical countries and presenting at the outpatient travel medicine clinic of the University of Munich, Germany, between 1999 and 2009 were analyzed for this study. Of these, 12.2% were diagnosed with skin disorders.

RESULTS

Main destinations visited were Asia (40%), Africa (27%) and Latin America (21%). Tourism in the form of adventure travel/backpacking (47%) and package holidays (23%) was the most common purpose of travel. The leading causes of skin disorders were arthropodal (23%), bacterial (22%), helminthic (11%), protozoan (6%), viral (6%), allergic (5%) and fungal (4%). The 10 most frequently diagnosed specific skin diseases associated with specific destinations were insect bites (17%, Southern Europe), cutaneous larva migrans (8%, Asia and Latin America), cutaneous leishmaniasis (2.4%, Mediterranean Region/Middle East), dengue fever (1.5%, Asia), rickettsioses (1.3%, Southern Africa), myiasis (0.8%, Central America), filarioses (0.7%, Africa), tick bites (0.6%, Central/Eastern Europe), schistosomiasis (0.6%, Africa) and tungiasis (0.6%, Africa). Travellers in sub-Saharan Africa had the highest relative risk of acquiring skin disorders.

CONCLUSION

As more than 20% of all skin disorders among returned travellers were caused by arthropods and about 50% by infectious pathogens, pre-travel consultations should include specific prophylaxis and consider the most important risk factor for the travel destination.

Skin infections in developing countries

PURPOSE OF REVIEW

In developing countries, where the majority of people have a low income and live in resource-poor settings, skin infections are prevalent. Data from recent studies provide insight into the most common skin infections and their management.

RECENT FINDINGS

Several studies confirm that skin infections account for the majority of pediatric mortality and morbidity in developing countries. They are prevalent in resource-poor settings and rural areas in certain parts of the world. Also, hot, humid climates and overcrowding predispose to skin infections. Most of the skin infections are curable with effective medication.

SUMMARY

Skin infections are of particular importance in developing countries. This review focuses on the most common skin infections and summarizes the most recent knowledge on the epidemiology, morbidity, and treatment in resource-poor settings.