Lesson of the week: Norwegian scabies misdiagnosed as an adverse drug reaction

Severe Scabies: A French Multi-centre Study Involving 95 Patients with Crusted and Profuse Disease and Review of the Literature

The aim of this multi-centre French retrospective study was to identify severe, i.e. crusted and profuse, scabies patients. Records were retrieved from 22 Dermatology or Infectious Diseases departments in the Ile-de-France from January 2009 to January 2015 to characterize epidemiology, demography, diagnosis, contributing factors, treatment features, and outcomes in severe scabies. A total of 95 inpatients (57 crusted and 38 profuse) were included. A higher number of cases was observed among elderly patients (>75 years), mostly living in institutions. Thirteen patients (13.6%) reported a history of previously treated scabies. Sixty-three patients (66.3%) had been seen by a previous practitioner for the current episode (up to 8 previous visits). Initial misdiagnosis (e.g. eczema, prurigo, drug-related eruptions, psoriasis) was documented in 41 patients (43.1%). Fifty-eight patients (61%) had already received 1 or more previous treatments for their current episode. Forty percent received corticosteroids or acitretin for an initial diagnosis of eczema or psoriasis. Median time from the onset of symptoms to the diagnosis of severe scabies was 3 months (range 0.3-22). Itch was present in all patients at diagnosis. Most patients (n=84, 88.4%) had comorbidities. Diagnostic and therapeutic approaches varied. Complications occurred in 11.5% of cases. To date, there is no consensus for diagnosis and treatment, and future standardization of is required for optimal management.

Crusted Scabies Induced Hypereosinophilic Syndrome

Crusted scabies causes extensive hyperkeratotic skin lesions, crusting, and scaling and is common in elderly and institutionalized patients. We present a case of crusted scabies in a patient with encephalopathy and diffuse exfoliative erythroderma. After extensive workup, the patient’s condition was attributed to hypereosinophilic syndrome due to crusted scabies. Skin condition, mental status, and eosinophilia improved with high-dose steroids in conjunction with topical permethrin and oral ivermectin.

Norwegian Scabies management after prolonged disease course: A case report

Introduction

Scabies is a well – known, commonly recognized, and frequently diagnosed pathology especially in children, close quarters, living facilities, and immunocompromised patients. An accelerated severe infestation of traditional scabies with limited treatment options is known as the rare entity of Norwegian or Crusted Scabies.

Case presentation

We present the history, clinical manifestations, medical treatments and surgical interventions of a patient with Norwegian Scabies of his hands, which rendered them nonfunctional prior to intervention. The patient was initially misdiagnosed and underwent inappropriate treatments for several years prior to our assessment, and ultimately required surgical intervention that was therapeutic.

Discussion

Norwegian, or Crusted, Scabies is a severe infestation of S. scabiei in which the mite load is extreme in comparison to traditional scabies. This manifests as scaly plaques that are often misdiagnosed for other hyperkeratotic skin lesions. With this misdiagnosis, improper treatments are often recommended, and can even accelerate the manifestation. Traditional scabies therapies can be effective, however often due significant disease progression due to diagnostic delay, invasive measures, such as surgical debridement like presented here, are the only option.

Conclusion

The patient presented in this case harbored a rare infection, known as Norwegian Scabies, for several years, with inappropriate medical therapy. Due to his prolonged inadequate treatments, his disease became so pronounced that the recommended medical treatments were no longer adequate, thus he required surgical debridements which ultimately allowed him to regain function in his hands.

The effects of climate factors on scabies. A 14-year population-based study in Taiwan

Scabies is a common infectious disease and can cause severe outbreaks if not controlled quickly. Besides personal contact history, environmental factors are also important. This study analyzed the effects of environmental climate factors on the incidence of scabies in Taiwan. We conducted a 14-year nationwide population-based study: a total of 14,883 patients with scabies infestation were enrolled. Monthly climate data were collected from Taiwan’s Central Weather Bureau, including data on temperature, relative humidity, total rainfall, total rain days, and total sunshine hours. The linear relationships between these climate factors and scabies infestations or other risk factors were examined by Pearson’s correlation analysis. Overall, the incidence of scabies was negatively correlated with temperature (γ = −0.152, p < 0.001), while being positively correlated with humidity (γ = 0.192, p < 0.001). This useful information may provide evidence for lowering humidity at nursing facilities, hospitals, and military camps with scabies infestations, which may help to reduce its spread and prevent outbreaks.

Crusted scabies in the burned patient

The objectives of this study were 1) to describe a case of crusted scabies (CS) in a burned patient, which was primarily undiagnosed and led to a nosocomial outbreak in the burn unit; 2) to analyze and discuss the difficulties in diagnosing and treating this subset of patients with burn injury; and 3) to design a treatment strategy for future patients. Case analysis and literature review were performed. The index patient had undiagnosed crusted scabies (sive Scabies norvegica) with the ensuing mite hyperinfestation when admitted to the department with minor acute dermal burns. Conservative healing and autograft healing were impaired because of the condition. Successful treatment of the burns was only accomplished secondarily to scabicide treatment. An outbreak of scabies among staff members indirectly led to diagnosis. CS is ubiquitous, and diagnosis may be difficult. This is the first report of a burned patient with CS in the English language literature. CS is also highly contagious and may lead to a nosocomial outbreak. Furthermore, CS seems to have a detrimental impact on the burned patient's course of treatment. A scabicide treatment is necessary to guarantee successful treatment of the burns.

Scabies

Scabies is an ectoparasite caused by the mite Sarcoptes scabiei var hominis, an obligate human parasite. There are about 300 million cases of scabies in the world each year. Common predisposing factors are overcrowding, immigration, poor hygiene, poor nutritional status, homelessness, dementia, and sexual contact. Direct skin-to-skin contact between 15 and 20 minutes is needed to transfer the mites from one person to another. The diagnosis suspected with a clinical history of itch, worse at night, affecting other family members, clinical distribution, and appearance. Definite diagnosis relies on microscopic identification of the mites, eggs, or fecal pellets with 10% potassium hydroxide, ink enhancement, tetracycline fluorescence tests, or mineral oil; other methods include: epiluminescence light microscopy and S. scabiei DNA. The most commonly used treatment modalities are permethrin and ivermectin. Persistence of symptoms for 2-6 weeks after successful treatment is common. Most recurrences are because of reinfection from untreated contacts.

Atypically distributed cutaneous lesions of Norwegian scabies in an HIV-positive man in South India: a case report

INTRODUCTION

Immune-compromised subjects, especially those with underlying HIV disease, are prone to be infected with Norwegian scabies, where the cutaneous lesions are classically distributed over the extremities.

CASE PRESENTATION

We report the case of an HIV-positive 16-year-old man with severe crusted Norwegian scabies initially misdiagnosed as a dermal fungal infection. The patient had extensive, generalized, thick, hyperkeratotic, crusting, yellowish papule lesions distributed on the entire body from his scalp to his toes.The patient was started with Ivermectin and topical Permethrin, which eventually resulted in complete resolution. Interestingly, despite quarantining efforts, one of the patient's acquaintances and a healthcare worker acquired the symptoms of itching.

CONCLUSION

This atypical presentation of Norwegian scabies emphasizes the need to include scabies in the differential diagnosis when HIV-infected patients present with crusted, generalized cutaneous lesions.

Langerhans cell hyperplasia in scabies: a mimic of Langerhans cell histiocytosis

AIM

In the absence of mites, the histologic diagnosis of human scabies can be difficult. Scabies can mimic a variety of inflammatory and lymphoproliferative disorders. It is under-recognized that scabies can also mimic Langerhans cell histiocytosis.

METHODS

Sixteen examples of scabies were reviewed histologically and immunohistochemically (CD1a, CD3, CD20, CD30 and S100).

RESULTS

Immunohistochemical labeling showed florid CD1a and S100 positivity in most cases, indicative of Langerhans cell hyperplasia. Scattered CD30+ lymphocytes were also typically present, within a dense infiltrate, primarily composed of T lymphocytes and eosinophils.

CONCLUSION

Because of the prominent CD1a+/S100+ component, scabies can mimic Langerhans cell histiocytosis. This finding should be considered in conjunction with scattered CD30+ cells and clinical features to avoid misdiagnosis.

Nosocomial scabies

Scabies is a parasitic dermatosis with a worldwide distribution. This infestation affects millions of people annually and may cause large nosocomial outbreaks with considerable morbidity among patients and healthcare workers. Immunocompromised or elderly institutionalized patients admitted with unrecognized crusted scabies are the main source of nosocomial transmission. Factors that facilitate the development of hospital-acquired scabies and nosocomial epidemics are: poor knowledge of scabies epidemiology, unfamiliarity of healthcare workers with atypical presentations, long incubation period, diagnostic delay and incomplete monitoring. Within hospitals, containment of an outbreak relies on the strict implementation of appropriate infection control measures and treatment administration to contacts. It is associated with a considerable working and economic burden.

Scabies, pediculosis, bedbugs, and stinkbugs: uncommon presentations

Parasitic agents determine some of the most common skin disorders. Although well known, they could present different manifestations or be modified by individual or external factors that make their diagnosis or treatment difficult. This review will discuss some of the most prevalent parasitic infections, scabies, and pediculosis and also mention reactions determined by contact with certain insects that, although rarely found, could induce important skin reactions.

Unusual laboratory findings in a case of Norwegian scabies provided a clue to diagnosis

The diagnosis of Norwegian scabies was missed for a year for an elderly long-term-care facility resident. Serpiginous tracks were noted on the surface of Sabouraud dextrose agar used for fungal culture of the skin scrapings. This unusual laboratory manifestation must alert clinical microbiologists to the possible diagnosis of scabies.

Crusted scabies in a healthy infant

Crusted scabies is generally seen in mentally retarded and immunosuppressed individuals. We report the case of a patient with crusted scabies with neither systemic disease nor immunosuppression; all the lesions were cured with applications of 5% permethrin lotion.

Scabies incognito presenting as urticaria pigmentosa in an infant

Misdiagnosis is frequent in scabies of infants and children because of a low index of suspicion, secondary eczematous changes, and inappropriate therapy. Topical or systemic corticosteroids may modify the clinical presentation of scabies and that situation is referred to as scabies incognito. We describe a 10-month-old infant with scabies incognito mimicking urticaria pigmentosa.

Interventions for treating scabies

BACKGROUND

Scabies is a common public health problem with an estimated prevalence of 300 million. Infestation can cause considerable discomfort and intense itching. Severe adverse effects have been reported for some drugs used to treat scabies.

OBJECTIVES

The objective of this review is to assess the effects and toxicity of topical and systemic drug treatment for scabies.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline, Embase, military records, traditional medicine databases. We also contacted international specialist centres and drug manufacturers.

SELECTION CRITERIA

Randomised controlled trials of any drug treatment for scabies. Tolerability and toxicity were sought in any study of humans taking any drug treatments for scabies.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data.

MAIN RESULTS

Eleven trials were included (7 compared drug treatments, 2 compared treatment regimes, 1 compared the drug vehicle and 1 was a community intervention). Compared with placebo in one small trial, ivermectin was associated with a significant higher clinical cure rate at seven days. Permethrin appeared to be more effective than crotamiton for clinical and parasitic cure rates. Permethrin appeared to be better than gamma benzene hexachloride for clinical cure rates in two small trials but had no advantage in the largest trial (test for heterogeneity p< 0.001). Permethrin also appeared more effective in reducing itch persistance than gamma benzene hexachloride. There appeared to be no difference in clinical cure rates between crotamiton and gamma benzene hexachloride. Single trials assessed: the effectiveness of oral versus topical treatment (ivermectin versus benzyl benzoate); treatment vehicle (pork fat versus cold cream); and mass community treatment (ivermectin) but were too small to demonstrate an effect. No randomised trials of malathion were identified. Serious adverse drug reactions (including death and convulsions) have been reported in other studies of scabies drugs, most notably gamma benzene hexachoride and ivermectin.

REVIEWER'S CONCLUSIONS

The evidence that permethrin is more effective than gamma benzene hexachloride is inconsistent. Permethrin appears to have less potential serious drugs reactions than gamma benzene hexachloride although this is not derived from trial data. More research is needed of the safety and effectiveness of ivermectin and malathion compared to permethrin, on community management, and on different regimes and vehicles for topical treatment.