Control of large institutional scabies outbreaks

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.

[Scabies in old age]

Scabies is a frequent ectoparasitosis the prevalence of which also seems to increase in older patients. Correct and timely diagnosis of scabies in older age is hampered by atypical clinical manifestations, the potential lack of pruritus and a variety of differential diagnoses. Scabies crustosa, a highly contagious subtype due to the presence of innumerable mites, is of particular importance. It predominantly occurs in immunosuppressed patients as well as in mentally or physically disabled persons and is the most important source of scabies outbreaks in residential and nursing homes. This article reviews the diagnosis and treatment of scabies and the strategies for managing outbreaks with special reference to older patients.

Do we know how scabies outbreaks in residential and nursing care homes for the elderly should be managed? A systematic review of interventions using a novel approach to assess evidence quality

Currently no national guidelines exist for the management of scabies outbreaks in residential or nursing care homes for the elderly in the United Kingdom. In this setting, diagnosis and treatment of scabies outbreaks is often delayed and optimal drug treatment, environmental control measures and even outcome measures are unclear. We undertook a systematic review to establish the efficacy of outbreak management interventions and determine evidence-based recommendations. Four electronic databases were searched for relevant studies, which were assessed using a quality assessment tool drawing on STROBE guidelines to describe the quality of observational data. Nineteen outbreak reports were identified, describing both drug treatment and environmental management measures. The quality of data was poor; none reported all outcome measures and only four described symptom relief measures. We were unable to make definitive evidence-based recommendations. We draw on the results to propose a framework for data collection in future observational studies of scabies outbreaks. While high-quality randomised controlled trials are needed to determine optimal drug treatment, evidence on environmental measures will need augmentation through other literature studies. The quality assessment tool designed is a useful resource for reporting of outcome measures including patient-reported measures in future outbreaks.

Rate and factors for scabies recurrence in children in Saudi Arabia: a retrospective study

Background

Despite the fact that several scabies outbreaks emerged in schools in Saudi Arabia in 2018, no study has investigated the risk of scabies recurrence among children in Saudi Arabia. This study aimed to estimate the rate of scabies recurrence and identify factors that were associated with an increased risk of recurrence among children.

Methods

This is a multi-center retrospective study of children (age < 14 years) who were diagnosed between May 20, 2015 and September 12, 2018 with one or multiple recurrent scabies at the Ministry of National Guard Health Affairs (MNGHA) hospitals and clinics in Saudi Arabia. Data were obtained from an electronic health system, BestCare database.

Results

A sample of 264 children analyzed (mean age of 6.7 years) resulted in a cumulative number of 316 scabies diagnoses in which 86 (27.2%) experienced scabies recurrence (at least once). Independent factors associated with a high risk of scabies recurrence: older children (adjusted hazard ratio [aHR], 1.036; 95% CI, 1.002–1.072; P = 0.039), female gender (aHR, 1.734; 95% CI, 1.329–2.262; P = 0.001), Western region of Saudi Arabia (aHR, 1.548; 95% CI, 1.115–2.151; P = 0.009), and 2nd tertile season [May to August] (aHR, 2.368; 95% CI, 1.706–3.288; P = 0.001).

Conclusions

The study demonstrated that the recurrence rate of scabies among children is high. Older children, the female gender, the Western region of Saudi Arabia, and the seasonality were independently associated with an increased risk of scabies recurrence. High temperature and low humidity should be explored as leading factors for scabies infestations in Saudi Arabia. Findings derived from this study may be useful for clinicians and governments in optimizing clinical management of scabies cases and contacts.

Implementation and evaluation of an algorithm for the management of scabies outbreaks

Background

Infestations with scabies mites are a global burden affecting individuals of all ages, classes and ethnicities. As poor sanitation and overcrowding favor the transmission of this highly contagious disease, epidemic outbreaks are frequently observed among displaced persons and asylum seekers. Due to the growing influx of refugees during the last years, public health authorities in host countries are frequently confronted with the challenge to treat individuals with diagnosed or suspected scabies promptly and effectively to avoid further spreading of the infestation.

This study aimed to establish a straightforward and efficient algorithm for rapid screening and treatment of large numbers of patients with confirmed or suspected scabies infestations.

Methods

Forty-eight individuals (58% males, mean age 22.4 yrs.) from Syria with suspected scabies infestation were allocated to 3 colour-coded groups: (1) no signs or symptoms of infestation, (2) itch only, and (3) itch and typical skin lesions. Patients were treated with a single (group 1) or two doses of oral ivermectin at an interval of 7 days (group 2), or with a combination of 2 doses of ivermectin plus 2 applications of permethrin ointment at an interval of 7 days (group 3). Follow-ups were performed 4 weeks after initial treatments.

Results

All individuals with signs and/or symptoms of infestation had improved skin lesion; in 10/11 (90.9%) lesion had completely resolved. All individuals with initial itch only (n = 32) reported improvement of its intensity or complete resolution. None of the patients of group 1 developed itch or skin lesions. The algorithm was reapplied in 4 individuals (8.3%) after 4 weeks and the outbreak was completely controlled after 8 weeks. Colour-coding ensured fast flow of information between health-care providers at the interfaces of the algorithm.

Conclusions

Our algorithm proved to be both highly efficient for treatment of large numbers of patients with suspected or diagnosed scabies infestation as well as for prevention of spreading of the disease. Hence, this algorithm is well suited for the management of scabies mass outbreaks.

Infected with Scabies Again? Focus in Management in Long-Term Care Facilities

Scabies is a significant public health condition in long-term care facilities, plaguing even developed countries. Although treatments are available, eradication and control of scabies cases still remain a challenge due to delays in diagnosis and difficulties in maintaining preventive and surveillance measures. Prompt treatment of patients and their contacts that are affected, along with concomitant education of health staff and family members, are paramount. Environmental disinfestation is also a concern.

Scabies outbreak among healthcare workers in a German acute care hospital

BACKGROUND

This article reports on a scabies outbreak among healthcare workers (HCW) in an acute care hospital. The outbreak was associated with a patient suffering from a chronic skin disease that was later diagnosed as crusted scabies.

OBJECTIVE

The objective was to determine the outbreak drivers and define a prevention strategy against future outbreaks.

METHODS

All staff that had contact with the patient were treated with 5% permethrin ointment. An interdisciplinary outbreak investigation team was established. The team conducted a questionnaire-based case-control study.

FINDINGS

After the permethrin treatment, no further case was found. Twenty-seven HCWs who had contact with the index patient answered the questionnaire (response rate 73%). The outbreak questionnaire revealed 13 cases of secondary scabies among HCWs. In the multivariable analysis, a lack of glove use (odds ratio [OR], 9.8; P value = 0.036) and frequent close physical contact (OR, 8.151; P value = 0.038) were associated with increased risk of scabies acquisition.

DISCUSSION

The scabies outbreak was most likely driven by three factors: an index patient with crusted scabies; a delayed diagnosis of this patient; and close physical contact without gloves during his hospital stay. The use of disposable gloves for patients with unclear dermatological diagnosis have the potential to limit future scabies outbreaks.

[Scabies as an occupational disease]

Scabies is an infectious skin disease caused by the human itch mite (Sarcoptes scabiei var. hominis). It is mainly transmitted by direct skin-to-skin contact. The spread of scabies can cause major difficulties in healthcare institutions, particularly in residential homes for the elderly. The disease is characterized by intense nocturnal itching, erythematous papules arranged in a linear order, and scratching resulting in excoriations. The diagnosis is confirmed by identification of the mite or by finding one or more mite tunnels in the skin. An individually occurring case does not need to be reported. If two or more cases occur in the same institution, the company physician and the appropriate public health department are to be informed in Germany. In case of a suspected scabies infection in medical personnel due to exposure in their work setting, medical notification to the statutory occupational accidents' insurance (Nr. 3101) is to be issued in accordance with § 202, Volume VII of the German Social Code. First line treatment is topical therapy with 5 % permethrin. If scabies control is required in an institution, systemic treatment with ivermectin may be considered. In the case of a scabies outbreak, all patients, contact persons, and staff must be treated simultaneously.

Scabies: an ancient global disease with a need for new therapies

BACKGROUND

Scabies is an ancient disease (documented as far back as 2500 years ago). It affects about 300 million people annually worldwide, and the prevalence is as high as about 60% in Indigenous and Torres Strait Islander children in Australia. This is more than six times the rate seen in the rest of the developed world. Scabies 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. This causes a substantial social and economic burden especially in resource poor communities around the world.

DISCUSSION

Very few treatment options are currently available for the management of scabies infection. In this manuscript we briefly discuss the clinical consequences of scabies and the problems found (studies conducted in Australia) with the currently used topical and oral treatments. Current scabies treatment options are fairly ineffective in preventing treatment relapse, inflammatory skin reactions and associated bacterial skin infections. None have ovicidal, antibacterial, anti-inflammatory and/or anti-pruritic properties. Treatments which are currently available for scabies can be problematic with adverse effects and perhaps of greater concern the risk of treatment failure. The development of new chemical entities is doubtful in the near future. Though there may be potential for immunological control, the development of a vaccine or other immunotherapy modalities may be decades away. The emergence of resistance among scabies mites to classical scabicides and ineffectiveness of current treatments (in reducing inflammatory skin reactions and secondary bacterial infections associated with scabies), raise serious concerns regarding current therapy. Treatment adherence difficulties, and safety and efficacy uncertainties in the young and elderly, all signal the need to identify new treatments for scabies.

Development of Conventional and Real-Time Quantitative PCR Assays for Diagnosis and Monitoring of Scabies

Scabies remains the most prevalent, endemic, and neglected ectoparasitic infestation globally and can cause institutional outbreaks. The sensitivity of routine microscopy for demonstration of Sarcoptes scabiei mites or eggs in skin scrapings is only about 50%. Except for three studies using conventional or two-tube nested PCR on a small number of cases, no systematic study has been performed to improve the laboratory diagnosis of this important infection. We developed a conventional and a real-time quantitative PCR (qPCR) assay based on the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of S. scabiei. The cox1 gene is relatively well conserved, with its sequence having no high levels of similarity to the sequences of other human skin mites, pathogenic zoonotic mites, or common house dust mite species. This mitochondrial gene is also present in large quantities in arthropod cells, potentially improving the sensitivity of a PCR-based assay. In our study, both assays were specific and were more sensitive than microscopy in diagnosing scabies, with positive and negative predictive values of 100%. The S. scabiei DNA copy number in the microscopy-positive specimens was significantly higher than that in the microscopy-negative specimens (median S. scabiei DNA copy number, 3.604 versus 2.457 log10 copies per reaction; P = 0.0213). In the patient with crusted scabies, the qPCR assay performed on lesional skin swabs instead of scrapings revealed that the parasite DNA load took about 2 weeks to become negative after treatment. The utility of using lesional skin swabs as an alternative sample for diagnosis of scabies by PCR should be further evaluated.

Scabies in the nursing home

Scabies infection is antediluvian and ubiquitous both in developing and developed countries, yet often neglected. Scabies has a predilection to infect vulnerable subsets of population in crowding conditions, typically applicable to residents in the nursing home. The mite incites a unique immunological response from human hosts. Scabies does not manifest as a singular skin condition and may present atypically in older adults, the majority of nursing home residents, where delay has deleterious consequences. Further, pruritus or itching, the hallmark of scabies infection, is a common complaint from a variety of causes among older adults. Hence, the diagnosis is often delayed or missed. There are several pharmacological treatment options; long-term care practitioners need to understand the characteristics of each agent before selection. Even more relevant is the importance of nonpharmacological aspects of management, crucial in the success of averting spread or outbreaks in long-term care settings.

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.

Control of scabies outbreaks in an Italian hospital: an information-centered management strategy

BACKGROUND

Scabies is a dermatologic infestation caused by Sarcoptes scabiei. In industrialized countries, hospitals and other health structures can sometimes be hit. The optimal management of scabies outbreaks still has to be established, mass prophylaxis being one possible option.

METHODS

To identify the optimal approach to containing this re-emerging disease, a local health authority in Lombardy, Northern Italy, carried out an epidemiologic study into 2 scabies epidemics that took place from September to December 2012 in a 600-bed hospital with 26,000 admissions a year.

RESULTS

Over a 3-month period, there were 12 cases of scabies on 4 wards; 43 contacts received prophylaxis. When the first cases were identified, an information campaign involving all hospital personnel was immediately set up. Regular staff meetings were organized, and information leaflets were distributed to patients. Family doctors of discharged patients were informed of the outbreak.

CONCLUSION

A management model based on an information-centered strategy was used in place of mass prophylaxis to deal with scabies epidemics. The success of this approach was confirmed by the managers of the hospital involved (reduced expenditure for prophylactic drugs) and by hospital staff who did not have to deal with potential drug adverse effects.