Diagnosis, prevention, and treatment of scabies

Evidence underscoring immunological and clinical pathological changes associated with Sarcoptes scabiei infection: synthesis and meta-analysis

Background

Sarcoptes scabiei is one of the most impactful mammalian parasites. There has been much research on immunological and clinical pathological changes associated with S. scabiei parasitism across a range of host species. This rich body of literature is complex, and we seek to bring that complexity together in this study. We first (1) synthesise narrative reviews of immunopathological relationships to S. scabiei infection to construct overarching hypotheses; then (2) undertake a systematic meta-analysis of primary literature on immunological and clinical pathological changes; and lastly (3) contrast our findings from the meta-analysis to our synthesis from narrative reviews.

Methods

We synthesised 55 narrative reviews into two overarching hypotheses representing type I and type IV immune responses to S. scabiei infection. We then systematically extracted all literature reporting immunological variables, acute phase proteins, oxidant/antioxidant status, and erythrocytic, hepatological and nephrological changes, calculating 565 effect sizes between controls and sarcoptic mange affected groupings, refining (simplifying) hypotheses from narrative reviews.

Results

Immunological and clinical pathological parameters were most often studied in dogs (n = 12) and humans (n = 14). Combining immunological and clinical pathological information across mammalian species (n = 19) helped yield general insights into observed disease responses. This is evidenced by interspecific consensus in 27 immunological and clinical pathology variables (6/26 type I hypersensitivity, 3/20 type IV hypersensitivity, 6/10 oxidant/antioxidant status, 3/6 acute phase protein, 4/7 erythrocytic, and 5/10 hepatological/nephrological).

Conclusions

Elevated IgE, eosinophils and mast cells in type I hypersensitivity response corresponded to what was described in narrative reviews. Results from type IV hypersensitivity response suggested typical antibody response, however cell-mediated response was less evident. Some consensus of acute phase protein response and shifted oxidant/antioxidant balance and slight evidence of anemia. We highlight the need for mange/scabies studies to more routinely compare immunological and clinical pathological changes against controls, and include collection of a more standardised suite of variables among studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07635-5.

Efficacy and side effects of Blacksoap® as adjuvant therapy of scabies: a randomized control trial

BACKGROUND Blacksoap® is recognized as adjuvant therapy for scabies, but there has been no significant study on its effectiveness. This study aimed to compare the efficacy and safety between Blacksoap® and placebo on standard treatment for pruritus visual analog scale (VAS) and transepidermal water loss (TEWL) scores before and after receiving therapy. METHODS This single-blind randomized controlled trial was held in a boarding school in West Java in 2018. Subjects were recruited consecutively by random cluster sampling. Both groups received standard permethrin 5% cream therapy. The intervention group (n = 37) obtained Blacksoap®, while the control (n = 41) received baby soap. During the initial assessment, pruritus VAS and TEWL scores were taken. The cure rate, scores of pruritus VAS and TEWL, as well as side effects were assessed and compared during the first and fourth weeks. Data were analyzed using SPSS software version 20 (IBM Corp., USA) by a third party, mostly using non-parametric tests. RESULTS The cure rate of the intervention group was lower than the control in the first week with 75% versus 81% but higher in the fourth week with 97% versus 92%. There was no significant difference in the scores of pruritus VAS and TEWL, as well as side effects between the two groups. CONCLUSIONS The efficacy and safety of scabies treatment were similar between Blacksoap® and placebo adjunctive to standard treatment. Blacksoap®, on top of standard scabies treatment, might benefit patients by providing a higher cure rate in 4 weeks without any considerable adverse effects.

Crusted Scabies, a Neglected Tropical Disease: Case Series and Literature Review

Crusted scabies is a rare form of scabies that presents with more severe symptoms than those of classic scabies. It is characterized by large crusted lesions, extensive scales, thick hyperkeratosis, and contains a large number of highly contagious itch mites. Crusted scabies is more prevalent in immunocompromised, malnourished, and disabled individuals. This disease has been linked to a variety of health problems, including delayed diagnosis, infection risk, and high mortality, mainly from sepsis, and it has the potential to cause an outbreak due to its hyper-infestation, which makes it highly infectious. This article reports three cases of crusted scabies in North Sulawesi, Indonesia. Recent updates and a comprehensive review of the literature on the disease are also included, emphasizing the critical importance of early diagnosis and effective medical management of patients, which are necessary to prevent the complications and spread in communities.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Scabies: Application of the Novel Identify-Isolate-Inform Tool for Detection and Management

Scabies is a highly contagious, globally prevalent, parasitic skin infestation caused by Sarcoptes scabiei var. hominis, also known as the itch mite. There have been outbreaks not only in the developing world, but also in the developed world among refugees and asylum seekers. Once infested with scabies mites, symptomatic patients, as well as asymptomatic carriers, quickly spread the disease through direct skin-to-skin contact. Typically, symptoms of scabies are characterized by an erythematous, papular, pruritic rash associated with burrows. Treatment of scabies involves using topical or systemic scabicides and treating secondary bacterial infections, if present. Given the prevalence and contagiousness of scabies, measures to prevent its spread are essential. Through application of the novel Identify-Isolate-Inform (3I) Tool, emergency medical providers can readily identify risk factors for exposure and important symptoms of the disease, thus limiting its spread through prompt scabicide therapy; isolate the patient until after treatment; and inform local public health authorities and hospital infection prevention, when appropriate. Ultimately, these three actions can aid public health in controlling the transmission of scabies cases, thus ensuring the protection of the general public from this highly contagious skin infestation.

Scabies: A Neglected Global Disease

BACKGROUND

Scabies is a skin disease caused by an obligate human parasite mite Sarcoptes scabiei var. hominis. Children under the age of two and elderly individuals are at the greatest risk. Knowledge of this condition is important for an early diagnosis to be made and treatment to be initiated.

OBJECTIVE

The review aimed to familiarize physicians with the clinical manifestations, diagnosis, evaluation, and management of scabies.

METHODS

A search was conducted using Pubmed with the built-in "Clinical Queries" tool. The search term "Scabies" was used. The categories of "epidemiology", "diagnosis", "therapy", "prevention" and "prognosis" had a limited scope for primary clinical studies. Meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews were included. Only papers published in the English language were included. A descriptive, narrative synthesis was provided of the retrieved articles.

RESULTS

Worldwide, scabies affects 200 to 300 million individuals annually. The average prevalence is estimated to be 5 to 10% in children of developing countries. Transmission usually occurs after close prolonged skin-to-skin contact. Classic scabies is characterized by an erythematous papular eruption, serpiginous burrows, and intense pruritus. Sites of predilection include the webs of the fingers, volar wrists, lateral aspects of fingers, extensor surfaces of elbows and knees, waist, navel, abdomen, buttocks, groins, and, genitals. A clinical diagnosis of classic scabies can be made on the basis of the history and clinical findings. Other clinical variants include crusted scabies, nodular scabies, and bullous scabies. Finding the mite, ova, or fecal pellets on microscopic examination of scrapings taken from skin lesions confirms the diagnosis of scabies infestation. For eradication of scabies mites, the drugs of choice are topical permethrin and oral ivermectin.

CONCLUSION

Scabies is a highly contagious parasitic cutaneous disease that is stigmatising and debilitating. Increased awareness, accurate diagnosis, and prompt treatment are essential for the effective control of scabies and for the prevention of the spread of the disease.

Risk factors for treatment failure in scabies: a cohort study

BACKGROUND

Treatment failure, which occurs in about one-third of cases, is considered as a major factor in the increasing incidence of scabies in developed countries.

OBJECTIVES

To identify predictors of treatment failure of scabies in ambulatory populations.

METHODS

This multicentre study compared the clinical characteristics and treatment modalities between a group of patients with scabies treated successfully and another group who were not cured 3 months after antiscabies treatment.

RESULTS

In total 210 patients with a diagnosis of scabies were included, comprising 98 patients in the treatment success group and 112 in the treatment failure group. The main risk factors for treatment failure were (i) the use of only one type of treatment, topical benzyl benzoate (BB) or oral ivermectin, vs. the combination of both treatments [odds ratio (OR) 2·15, 95% confidence interval (CI) 1·22-3·77]; (ii) the use of a single intake (vs. two) of oral ivermectin (OR 10·2. 95% CI 4·49-23·2); (iii) intake of ivermectin during a meal vs. on an empty stomach (OR 4·31, 95% CI 1·89-9·84); (iv) absence of decontamination of furnishings (OR 8·72, 95% CI 3·50-21·8), in particular sofa and cushions (OR 5·90, 95% CI 2·34-14·9), mattresses (OR 4·16, 95% CI 1·35-12·8) or car seats (OR 6·57, 95% CI 3·27-13·2) and (v) absence of written documents explaining treatment modalities (OR 5·18, 95% CI 2·57-10·4). In multivariate analysis, treatment failure was mainly associated with (i) use of a single intake (vs. two) of ivermectin (OR 6·62, 95% CI 2·71-16·2); (ii) use of BB alone vs. two intakes of ivermectin (OR 3·51, 95% CI 1·55-7·95) and (iii) absence of decontamination of furniture with acaricides (OR 5·81, 95% CI 1·96-16·7).

CONCLUSIONS

Use of topical BB alone and a single intake (vs. two) of ivermectin are predictors of treatment failure.

Atypical crusted scabies in a patient with chronic liver disease caused by hepatitis B and D viruses

Crusted scabies is a less common variant of scabies that is highly contagious, difficult to treat and involves infestation by Sarcoptes scabiei var. hominis. The classical clinical presentation includes crusted, scaly and generally non-pruritic lesions usually located on the head, neck, palmar, plantar and periungual region. It was first described in Norway in 1848 in patients with leprosy who presented with crusted lesions. In this study, we report the case of a patient with crusted scabies with florid clinical manifestations and chronic liver disease due to hepatitis B and delta virus infection.

Molecular characteristics and serodiagnostic potential of chitinase-like protein from Sarcoptes scabiei

Scabies, caused by the mite Sarcoptes scabiei, is an allergic skin disease that affects millions of people and other mammals worldwide. This highly contagious parasitic disease is among the top 50 epidemic disease and is regarded as a neglected tropical disease. Diagnosis of scabies is difficult in the early stage, and the pathogenesis of scabies is not currently clear. Here, we expressed, identified and located the chitinase-like protein of S. scabiei (SsCLP), and evaluated its potential as an early-stage diagnostic antigen for rabbit scabies. Indirect ELISA using recombinant SsCLP (rSsCLP) exhibited diagnostic sensitivity of 94.4% (17/18) and specificity of 86.7% (26/30). Early diagnostic test after artificial infection of rabbits with S. scabiei for 1 week showed a positive detection rate of 96.7% (29/30). Immunolocalization assays showed that fluorescence signals were localized on the surface of mites and, in infected rabbits, were observed in keratinized skin and embedded mites. Intradermal skin tests of rabbits by injecting rSsCLP showed a wheal, flare and erythema reaction. These results suggest that S. scabiei chitinase-like protein is conducive to host invasion, participates in inducing the allergic response of the host, and is an effective antigen for the diagnosis of S. scabiei.

Parasitic infections in travelers and immigrants: part II helminths and ectoparasites

Travel and migration contribute to the emergence of certain parasites which may be imported into nonendemic areas. Noncontrolled importation of food products and animals may also contribute to the diagnosis of infections caused by helminths in nonendemic countries. Some helminth infections such as strongyloidiasis may be life-threatening, especially in immunocompromised patients, and outcome depends on correct diagnosis and treatment. Other helminth infections are neglected tropical diseases associated with chronic disease and/or disability. Major challenges concern the development of improved diagnostic techniques, safer and more effective drug therapies and identification of markers of response to treatment. The study of these imported infections in travelers and immigrants may provide opportunities for research which may not be readily available in resource-poor endemic countries. Updated reviews and guidelines are necessary as new data become available. The second part of this review focuses on infections in travelers and immigrants caused by helminths and ectoparasites.

Superiority of ivermectin 1% cream over metronidazole 0·75% cream in treating inflammatory lesions of rosacea: a randomized, investigator-blinded trial

BACKGROUND

Few therapeutic alternatives currently exist in the treatment of papulopustular rosacea (PPR).

OBJECTIVES

To demonstrate superiority of once-daily ivermectin 1% cream (IVM 1%) once daily vs. twice-daily metronidazole (MTZ 0·75%) cream, regarding percentage reduction of inflammatory lesions in subjects with moderate to severe PPR.

METHODS

In this Phase 3, investigator-blinded, randomized, parallel-group study, subjects received IVM 1% once daily, or MTZ 0·75% twice daily over 16 weeks. Efficacy assessments were inflammatory lesion counts and Investigator's Global Assessment (IGA). Safety assessments included incidence of adverse events (AEs) and local tolerance parameters. Subjects evaluated their disease following a 5-grade scale and completed questionnaires.

RESULTS

A total of 962 subjects were randomized to receive IVM 1% (n = 478) or MTZ 0·75% (n = 484). At week 16, IVM 1% was significantly superior to MTZ 0·75% in terms of reduction from baseline in inflammatory lesions (83·0% vs. 73·7%; P < 0.001), observed as early as week 3 (Last Observation Carried Forward, LOCF). IGA results (subjects 'clear' or 'almost clear') also favoured IVM 1%: 84·9% vs. 75·4%, respectively (P < 0.001). Incidence of AEs was comparable between groups and local tolerability was better for IVM 1%. More subjects receiving IVM rated their global improvement as 'excellent' or 'good.'

CONCLUSIONS

Ivermectin 1% cream was significantly superior to MTZ 0·75% cream and achieved high patient satisfaction.

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.