A risk-benefit assessment of agents used in the treatment of scabies

Clinical practice guidelines for the diagnosis and treatment of scabies

Scabies, caused by the Sarcoptes scabiei var hominis mite burrowing into the skin, is a highly contagious disease characterized by intense nocturnal itching. Its global impact is considerable, affecting more than 200 million individuals annually and posing significant challenges to healthcare systems worldwide. Transmission occurs primarily through direct skin-to-skin contact, contributing to its widespread prevalence and emergence as a substantial public health concern affecting large populations. This review presents consensus-based clinical practice guidelines for diagnosing and managing scabies, developed through the fuzzy Delphi method by dermatology, parasitology, pediatrics, pharmacology, and public health experts. The presence of burrows containing adult female mites, their eggs, and excreta is the diagnostic hallmark of scabies. Definitive diagnosis typically involves direct microscopic examination of skin scrapings obtained from these burrows, although dermoscopy has become a diagnostic tool in clinical practice. Treatment modalities encompass topical agents, such as permethrin, balsam of Peru, precipitated sulfur, and benzyl benzoate. In cases where topical therapy proves inadequate or in instances of crusted scabies, oral ivermectin is recommended as a systemic treatment option. This comprehensive approach addresses the diagnostic and therapeutic challenges associated with scabies, optimizing patient care, and management outcomes.

Skin diseases in rural Nyala, Sudan (in a rural hospital, in 12 orphanages, and in two refugee camps)

Skin diseases are considered to be common in Nyala, Sudan. This study was carried out to verify the prevalence of skin diseases in Nyala. This prospective observational study included skin examination of a total of 1802 people: 620 patients who were evaluated in the outpatient clinics (OC) and 1182 people from orphanages and refugee camps (ORC) in Nyala, Sudan. χ² test was used. The total prevalence of skin disorders in the sample was 92.6% (1670/1802). One thousand and fifty of 1182 (88.8%) people from ORC had a skin disorder. The most common skin diseases in this community were: fungal infections (32.6%), dermatitis/eczema (10.5%), bacterial skin infections (10.3%), disorders of skin appendages (8.7%), parasitic infestations (7.7%), atrophic skin disorders (7.4%), disorders of pigmentation (7.4%), hypertrophic skin disorders (6.4%), viral infections (5.8), benign neoplasm (1.9%), dermatoses due to animal injury (0.4%), bullous dermatoses (0.1%), and malignant neoplasm (0.1%). Hypertrophic and atrophic disorders of the skin were mainly lesions of scarification (mostly atrophic) (5.7%) and keloids (5.6%). Fungal infection, bacterial infection, and parasitic infestation were more common in the ORC group, while dermatitis and eczema, disorders of skin appendages, hypertrophic and atrophic disorders of the skin, disorders of pigmentation, and benign neoplasm were more common in the OC group. The prevalence of skin diseases in the rural Nyala was more than our expectation and was dominated by infectious skin diseases. In addition, infectious skin diseases were more common in ORC rather than OC.

A chitinase-like protein from Sarcoptes scabiei as a candidate anti-mite vaccine that contributes to immune protection in rabbits

BACKGROUND

Scabies is caused by Sarcoptes scabiei burrowing into the stratum corneum of the host's skin and is detrimental to the health of humans and animals. Vaccines are an attractive alternative to replace the acaricides currently used in their control.

METHODS

In the present study, the S. scabiei chitinase-like protein 5 (SsCLP5) was characterized and recombinant SsCLP5 (rSsCLP5) was evaluated as a candidate vaccine protein for anti-mite protection in rabbits. The expression, characterization and immunolocalization of SsCLP5 were examined. Vaccination experiments were performed on three test groups (n = 12 per group) immunized with purified rSsCLP5. Control groups (n = 12 per group) were immunized with PBS, QuilA saponin or empty vector protein. After challenge, the inflammatory reaction and skin lesions were graded and rSsCLP5 indirect ELISA was used to detect antibody IgG levels in serum samples at the time of vaccination and post-challenge.

RESULTS

The results showed that rSsCLP5 had high immunoreactivity and immunogenicity. In S. scabiei, SsCLP5 had a wide distribution in the chewing mouthpart, legs and exoskeleton, especially the outer layer of the exoskeleton. Vaccination with rSsCLP5 resulted in 74.3% (26/35) of rabbits showing no detectable lesions after challenge with S. scabiei.

CONCLUSIONS

Our data demonstrate that rSsCLP5 is a promising candidate for a recombinant protein-based vaccine against S. scabiei. This study also provides a method for studying scabies vaccine using rabbit as an animal model and a basis for screening more effective candidate proteins.

Scabies in the developing world--its prevalence, complications, and management

Scabies remains one of the commonest of skin diseases seen in developing countries. Although its distribution is subject to a cycle of infection, with peaks and troughs of disease prevalence, this periodicity is often less obvious in poor communities. Scabies is a condition that affects families, particularly the most vulnerable; it also has the greatest impact on young children. Largely through the association with secondary bacterial infection caused by group A streptococci and Staphylococcus aureus, the burden of disease is compounded by nephritis, rheumatic fever and sepsis in developing countries. However, with a few notable exceptions, it remains largely neglected as an important public health problem. The purpose of this review is to provide an update on the current position of scabies with regard to its complications and control in resource-poor countries.

Macrocyclic Lactone Endectocides

The macrocyclic lactone endectocides such as ivermectin, abamectin, selamectin and moxidectin have revolutionized the treatment of parasitic diseases in animals, being active against internal and external parasites. Ivermectin was introduced into veterinary medicine in the 1980s and since that time a number of related compounds have been introduced. In the treatment of internal parasites they complement the use of levamisole and the benzimidazoles, but in recent years they have found utility in treating external insect parasites. These agents show very low levels of toxicity under most circumstances. However, they are neurotoxic particularly in subpopulations of animals with mutations in the MDR1 gene. Toxicity may be also seen during off-label use, possibly because the doses used have been extrapolated from use in other animals. Regardless of these considerations, the macrocyclic lactone endectocides are extremely effective and safe drugs in the treatment of parasitic diseases of animals.

The Scourge of Sarcoptes: Oral Ivermectin for Scabies

OBJECTIVE

To review the use of the oral antiparasitic ivermectin in the treatment of scabies, with an emphasis on its use in the elderly and in long-term care settings.

DATA SOURCE

A MEDLINE/PUBMED search was conducted to identify pertinent studies, case reports, letters, and reviews in the English language. All articles published from 1980 to October 2003 were reviewed. Additional references were obtained from the bibliographies of these articles.

STUDY SELECTION

All studies evaluating ivermectin in the context of scabies mite infestation.

DATA SYNTHESIS

The semisynthetic macrocyclic lactone ivermectin has been available since the early 1980s as a broad-spectrum antiparasitic agent in animals and humans. This agent, which works by suppressing motor nerve conduction leading to parasite paralysis and death, was first used in ectoparasitic diseases (i.e., those caused by lice and mites) shortly after commercial introduction. A large body of literature, mainly uncontrolled case reports and series, has since evolved. However, these reports and results of the small number of placebo- and/or active-controlled studies have demonstrated the favorable response of both classic and crusted scabies to single- and multiple-dose oral ivermectin. Adverse reactions to the drug are uncommon, with the exception of a transient, new onset, or mild increase in existing pruritus soon after drug ingestion, which is thought to be a hypersensitivity reaction to dead mites and/or their products.

CONCLUSION

Oral ivermectin may prove to be a time- and labor-saving alternative to topical scabicide treatments, especially in the institutional setting where labor shortages make the management of scabies outbreaks a true challenge. However, the use of this agent does not change the need to decontaminate the environment (clothing, bedding, bed clothes, and, in selected cases, floors and walls) in order to truncate an outbreak and prevent reinfestation.

Distribution of Lindane in Water, Sediment, and Fish from the Warri River of the Niger Delta, Nigeria

This paper is the first attempt to quantify the levels and the distribution pattern of lindane in the surface water, sediment and fish (Chrysichthys furcatus and Tilapia zilli). The samples were collected from three stations (Ovwian, Ekakpamre, and Ovu) of the Warri River in the western Niger Delta of Nigeria in 2006: during the dry (January-April) and wet seasons (May-August). The analysis included a total of 96 samples made up of 24 samples each for water, sediment, and fish. The pesticide levels were analysed using high performance liquid chromatography to elucidate its distribution in various environmental compartments. Residue levels in the matrices ranged from below the detection limit (BDL) to 1.37μg L-1 in water, BDL to 12.66 μg g-1 dry weight (dw) in sediment, BDL to 16.67 μg g-1dw in Chrysichthys furcatus, and BDL to 0.15 μg g-1dw in Tilapia zilli. The observed values were above the ecological benchmarks (0.01 μg L-1) recommended by the Nigerian Environmental Protection Agency and European Union. They were also relatively higher than in previous studies on the Nigerian environment, which calls for regular monitoring of the Niger Delta water bodies.

Interventions for treating scabies

BACKGROUND

Scabies is an intensely itchy parasitic infection of the skin caused by the Sarcoptes scabiei mite. It is a common public health problem with an estimated global prevalence of 300 million cases. Serious adverse effects have been reported for some drugs used to treat scabies.

OBJECTIVES

To evaluate topical and systemic drugs for treating scabies.

SEARCH STRATEGY

In February 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE, EMBASE, LILACS, and INDMED. In March 2007, we also searched the grey literature and sources for registered trials. We also checked the reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials of drug treatments for scabies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Results were presented as relative risks with 95% confidence intervals and data combined where appropriate.

MAIN RESULTS

Twenty small trials involving 2392 people were included. One trial was placebo controlled, 16 compared two or more drug treatments, two compared treatment regimens, and one compared different drug vehicles.Fewer treatment failures occurred by day seven with oral ivermectin in one small trial (55 participants). Topical permethrin appeared more effective than oral ivermectin (85 participants, 1 trial), topical crotamiton (194 participants, 2 trials), and topical lindane (753 participants, 5 trials). Permethrin also appeared more effective in reducing itch persistence than either crotamiton (94 participants, 1 trial) or lindane (490 participants, 2 trials). One small trial did not detect a difference between permethrin (a synthetic pyrethroid) and a natural pyrethrin-based topical treatment (40 participants). No significant difference was detected in the number of treatment failures between crotamiton and lindane (100 participants, 1 trial), lindane and sulfur (68 participants, 1 trial), benzyl benzoate and sulfur (158 participants, 1 trial), and benzyl benzoate and natural synergized pyrethrins (240 participants, 1 trial); all were topical treatments. No trials of malathion were identified. No serious adverse events were reported. A number of trials reported skin reactions in participants randomized to topical treatments. There were occasional reports of headache, abdominal pain, diarrhoea, vomiting, and hypotension.

AUTHORS' CONCLUSIONS

Topical permethrin appears to be the most effective treatment for scabies. Ivermectin appears to be an effective oral treatment. More research is needed on the effectiveness of malathion, particularly when compared to permethrin, and on the management of scabies in an institutional setting and at a community level.

Safety of benzyl benzoate lotion and permethrin in pregnancy: a retrospective matched cohort study

OBJECTIVE

To assess the safety of benzyl benzoate lotion (BBL) and permethrin, topical treatments for scabies, during pregnancy.

DESIGN

A retrospective controlled cohort study.

POPULATION

Refugee and migrant women attending antenatal clinics (ANC) on the Thai-Burmese border between August 1993 and April 2006.

METHODS

Women treated with either BBL (25%) or permethrin (4%) were identified from a manual search of antenatal records. Each case of scabies was matched with four scabies-free controls for gravidity, age, smoking status, malaria, period of treatment and gestational age at treatment. Conditional Poisson regression was used to estimate risk ratios for outcomes of pregnancy (proportion of abortions, congenital abnormalities, neonatal deaths, stillbirths and premature babies), mean birthweight and estimated median gestational age, for scabies and scabies-free women, independently for BBL and permethrin.

RESULTS

There were no statistically significant differences in pregnancy outcomes between women who were treated with either BBL (n = 444) compared with their matched controls (n = 1,776) or permethrin (n = 196) treated women and their matched controls (n = 784). Overall, only 10.9% (n = 66) of treatments were in the first trimester. Retreatment rates were higher with BBL 16.4%, than permethrin 9.7%, P = 0.038. Scabies was more common during cooler periods.

CONCLUSION

We found no evidence of adverse effects on pregnancy outcome due to topical 25% BBL or 4% permethrin.

Scabies and Pediculosis Pubis: An Update of Treatment Regimens and General Review

Ectoparasites continue to be a common cause of skin disease throughout the world. The present article dissects the epidemiological profile and treatment of both Sarcoptes scabiei variant hominis and pediculosis pubis.

Scabies

Scabies is a neglected parasitic disease that is a major public health problem in many resource-poor regions. It causes substantial morbidity from secondary infections and post-infective complications such as acute post-streptococcal glomerulonephritis. Disease control requires treatment of the affected individual and all people they have been in contact with, but is often hampered by inappropriate or delayed diagnosis, poor treatment compliance, and improper use of topical compounds such as permethrin, lindane, or benzyl benzoate. In addition to concerns over toxicity with such compounds, parasite resistance seems to be increasing. Oral ivermectin is an alternative that has been used successfully in community control programmes. Plant derivatives such as turmeric, neem, and tea tree oil are also promising future treatments. The disease is strongly associated with poverty and overcrowding, and the associated stigma can ostracise affected individuals. Treatment of scabies in poor countries needs to integrate drug treatment programmes with efforts to improve the socioeconomic conditions and education programmes to reduce stigma. We expect the future to bring more sensitive and specific clinical and laboratory-based diagnostic methods, as well as new therapeutic strategies.

Dermal absorption of permethrin following topical administration

OBJECTIVE

Permethrin is an insecticide used in the treatment of lice and scabies infections. Although its efficacy and safety have been well documented, pharmacokinetic data are sparse. The objective of this study was to determine the systemic exposure of permethrin and the duration of residence in the human body following topical administration.

METHODS

The study consisted of three parts. In six young healthy men (part 1), 50 ml of an ethanolic solution containing 215 mg permethrin (cis/trans: 25/75) was administered to the hair of the head. In another six young healthy men (part 2) and in six male or female scabies patients (part 3), 60 g of cream containing 3 g permethrin was administered to the skin of the whole body. Urine was collected up to 168 h post-dose. Urinary excretion of the main metabolite of permethrin, 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, and its conjugates was measured using a gas chromatography/electron capture detection method.

RESULTS

Pharmacokinetics were similar in all study parts. The time of maximal urinary excretion rate was 12.3, 20.0 and 14.6 h, terminal elimination half-life was 32.7, 28.8 and 37.8 h and urinary recovery of the metabolite reached 0.35, 0.47 and 0.52 M percent of the permethrin dose, respectively, in parts 1, 2 and 3 (means). The treatment was well tolerated.

CONCLUSIONS

The extent of systemic exposure following external therapeutic administration of permethrin is very low compared with doses used for preclinical toxicity studies, and elimination is virtually complete after 1 week. These data provide the pharmacokinetic basis for the clinical safety of topical permethrin.

Scabies: more than just an irritation

Human scabies, caused by skin infestation with the arthropod mite, Sarcoptes scabiei, typically results in a papular, intensely pruritic eruption involving the interdigital spaces, and flexure creases. Recent research has led to a reassessment of the morbidity attributable to this parasite in endemic communities, particularly resulting from secondary skin sepsis and postinfective complications including glomerulonephritis. This has led to studies of the benefits of community based control programmes, and to concerns regarding the emergence of drug resistance when such strategies are employed. The renewed research interest into the biology of this infection has resulted in the application of molecular tools. This has established that canine and human scabies populations are genetically distinct, a finding with major implications for the formulation of public health control policies. Further research is needed to increase understanding of drug resistance, and to identify new drug targets and potential vaccine candidates.

Arthropods in dermatology

Arthropods are important in medicine for a multitude of reasons. Their bites and stings may induce allergic reactions, ranging from annoying to life-threatening. Many arthropod products are also capable of inciting allergic responses in sensitized persons. In recent years, bites and stings have gained greater attention owing to increased concern about disease transmission. A common hypersensitivity response to arthropod bites, stings, and products is papular urticaria. This eruption occurs primarily in children, who eventually "outgrow" this disease, probably through desensitization after multiple arthropod exposures. Papular urticaria is most often caused by fleas or bedbugs, but virtually any arthropod is capable of inducing such a reaction. Two arthropod classes of medical importance are the Arachnida (spiders, scorpions, ticks, and mites) and the Insecta (lice, fleas, bedbugs, flies, bees, and ants). Animals in these two classes are probably responsible for more morbidity and mortality worldwide than are any other group of venomous creatures. In general, the diagnosis of arthropod bites and stings is dependent on maintenance of a high index of suspicion and familiarity with the arthropod fauna not only in one's region of practice, but also in the travel regions of one's patients. Learning objective At the completion of this learning activity, participants should be familiar with the clinical manifestations caused by a variety of arthropods as well as the treatment and possible sequelae of arthropod attacks.

Prevalence of skin diseases in Ibadan, Nigeria

AIM

To study the pattern of skin diseases in patients attending the skin clinic of the University College Hospital, Ibadan, Nigeria, and to compare our findings with studies performed earlier in the same clinic.

PATIENTS AND METHODS

The study involved 1091 new patients who had attended the skin clinic of the University College Hospital, Ibadan, Nigeria, between January 1994 and December 1998. The patients were examined by the authors, and laboratory investigations were ordered when necessary to make a diagnosis.

RESULTS

An increased prevalence of eczema, idiopathic pruritus, urticaria, connective tissue diseases, and fixed drug eruptions was observed. Infections, such as scabies, candidiasis, and tinea versicolor, had also increased. Pyoderma, leprosy, onchocerciasis, and dermatophytoses showed a decline. Psoriasis was uncommon, although there was a slight increase in prevalence. Vitiligo and alopecia were stable. Cutaneous tuberculosis, such as lupus vulgaris, was rare.

CONCLUSIONS

Allergic conditions have increased; connective tissue disorders, such as systemic lupus erythematosus, scleroderma, and discoid lupus erythematosus, have also increased. Cutaneous disorders associated with human immunodeficiency virus infection, such as seborrheic dermatitis, have increased. Health workers need to be educated on the management and treatment of these conditions, and should be advised to refer patients to appropriate health facilities when necessary.

Controlling scabies in institutional settings: a review of medications, treatment models, and implementation

Scabies is a global problem and a significant source of morbidity in nursing home residents and workers because of its highly contagious nature. It is also a problem in hospitals that care for the elderly, the debilitated, and the immunocompromised. New outbreaks continue to occur, despite controlling the recurrent epidemics. Scabies manifests as papules, pustules, burrows, nodules, and occasionally urticarial papules and plaques. Most of the patients with scabies experience severe pruritus. A subset of patients have crusted or Norwegian scabies. These patients, who are usually debilitated or immunocompromised, do not experience the urge to scratch, and therefore do not scratch their own skin. Diagnosis of scabies is based on patient history, physical examination, and demonstration of mites, eggs, or scybala (black or brown football-shaped masses of feces of scabies) on microscopic examination. Scabies can be treated with topical or oral therapies. Topical treatments include 5% permethrin cream, 1% lindane (gamma benzene hexachloride) lotion, 6% precipitated sulfur in petrolatum, crotamiton, malathion, allethrin spray, and benzyl benzoate. Ivermectin, the only oral treatment, is not approved for scabies in the US. Most authorities advocate using a scabicide several times, specifically once a week over a period of 2-3 weeks. In an outbreak of scabies in a nursing home, residents, staff, and frequent visitors should all be treated even if they are not symptomatic. Ivermectin is useful in treating patients with Norwegian or crusted scabies, or who are debilitated. Ivermectin has no serious reported adverse effects. Model treatment plans to stop scabies epidemics have been developed. These plans coordinate treatment of all persons exposed (including ivermectin for debilitated patients), isolation of infected patients, disinfection of objects that patients have come into contact with, and education and reassurance of the medical staff. Failure to coordinate notification, education, treatment, and disinfection leads to failure to control scabies epidemics. Control of epidemics of institutional scabies requires attention to treatment effects and logistics. Treatment is low risk, but cumbersome because many individuals need be treated. It is advisable to restrict, where possible, the number of staff members that deal with scabies patients to limit the spread of the scabies. Prolonged surveillance is required for the eradication of institutional scabies. While the foregoing plans require coordination of all involved personnel and sustained efforts, they are necessary to halt the spread of scabies to patients and staff, to enhance their morale, and to prevent deterioration of labor and public relations.

Scabies and pediculosis

Although scabies and pediculosis are difficult and widespread problems, there are many effective treatments available. Dermatologists play a major role in educating the public in prevention and diagnosis. Although patients are more aware and well informed of the infections because of the Internet and other sources, practitioners are often the most important source of information and treatment in helping to eradicate this worldwide problem.

Ivermectin

Ivermectin is a potent antiparasitic drug and the first commercially available member of a new class of drugs (macrocyclic lactones) that has been approved for human use. Ivermectin has already proven to be highly effective in the elimination of river blindness as a public health burden. Side effects have been minor, and patient acceptance is good. Promising results in off-label applications for ectoparasitic infestations are increasingly important as resistance to topical therapy becomes more prevalent Ivermectin represents an advance in the therapeutic armamentarium and should be considered in appropriate cases.

Scabies and pediculosis pubis: an update of treatment regimens and general review

The ectoparasites scabies and pediculosis pubis are common causes of skin rash and pruritus worldwide. They are transmitted primarily by person-to-person spread and are generally associated with low morbidity. The preferred treatment for scabies has generally been topical agents such as lindane and permethrin. Recently, ivermectin has demonstrated good efficacy in the treatment of scabies, and it may be of particular use in institutional outbreaks and in communities in which scabies is endemic. Combination treatment with topical agents and oral ivermectin may be necessary for crusted scabies. Treatment of pediculosis pubis is best accomplished with topical permethrin, lindane, or pyrethrins with piperonyl butoxide. Although resistance to these topical agents has been reported in head lice, decreased efficacy in the treatment of pediculosis pubis has not been reported.

Sulfur for scabies outbreaks in orphanages

Scabies outbreaks occurred in two large orphanages in Chiang Mai, Thailand. Since we were concerned about the availability, safety, and cost of scabicides in Thailand, sulfur in petrolatum was our choice for mass treatment of the children. We studied the efficacy of sulfur in children 2 months to 6 years of age. After the treatment, 47% and 71% of the 102 patients were cured in 2 weeks and 4 weeks, respectively. Only three preschool children developed a mild facial irritation after the first application. This agent is a safe and cheap choice for mass therapy.

Diagnosis and treatment of scabies: a practical guide

Scabies is a common, highly pruritic infestation of the skin caused by Sarcoptes scabiei var. Hominis. It is a very contagious parasitosis with specific lesions, such as burrows, and nonspecific lesions, such as papules, vesicles and excoriations. The typical areas of the body it affects are finger webs, wrists, axillary folds, abdomen, buttocks, inframammary folds and, in men, the genitalia. It is characterized by intense nocturnal pruritus. Scabies is spread through close personal contact (relatives, sexual partners, schoolchildren, chronically ill patients and crowded communities). Definitive diagnosis is made when the scabies mites or their eggs or fecal pellets can be identified on a light microscope. New techniques for diagnosis include the use of the epiluminiscence microscopy. The most common topical treatments for scabies include lindane and permethrin. Permethrin provides a greater margin of tolerability because of its low inherent toxicity and low percutaneous absorption. Oral ivermectin is the most recently developed treatment for scabies. A single oral dose of ivermectin 200 microg/kg of bodyweight is a well-tolerated and very effective treatment. It is especially indicated in crusted scabies, scabies in immunocompromised hosts and infestations in crowded communities. It is also useful as a simple treatment in the prophylaxis of close contacts.

Skin infections and infestations in geriatric patients

Geriatric patients develop infections, but many have a different appearance from what usually is expected. The difference depends on the age and immune status of the patient and the virulence of the organism. Differences may make recognition more difficult. Therapy may require different doses. Examples of the more common infections are detailed in this article.

Pharmacotherapy of ectoparasitic infections

Epizoonoses such as scabies, lice and cimicosis are common, vexing disorders that occur worldwide. Historically, many treatment modalities have been employed in the management of these disorders, and most of the drugs described in this review are of historical interest and no longer recommended or in widespread use because of their wide spectrum of adverse effects. More recently, reports documenting resistance against various antiectoparasite drugs, complicated and severe courses of the diseases, and adverse effects of drug therapy have prompted the development of new treatment strategies and drugs for optimal disease management. Because the strategies currently recommended for the treatment of ectoparasites differ worldwide, this review proposes a rational approach to selecting the best therapeutic agent by comparing the pharmacokinetics, pharmacodynamics, drug efficacy and adverse effects. A literature search of the currently Internet accessible libraries PubMed, Medline and Ideal library, of citations of articles found there, and from communications with the Federal Institute for Drugs and Medical Devices, Germany, was conducted based on this approach. One major observation of this literature search is that permethrin is the treatment of choice for lice and scabies in the US and in Great Britain, whereas lindane is still recommended for scabies in most other European countries because of its longer-standing record of effectiveness. Although permethrin has not yet been proven to be more effective than lindane in treating infections with these ectoparasites, it currently appears to have the best efficacy versus safety profile of topical treatments for scabies and lice. Ivermectin is a newer oral drug for the treatment of ectoparasites, which has been used with great success in the treatment of onchocercosis and other endoparasites. Although ivermectin appears to be a promising drug, its role in the treatment of ectoparasitic infections will be clarified as more study data become available. Finally, it is important to emphasise the clinical aspects of ectoparasite therapy and that providing the patient with optimal instructions on the use of topical therapeutics is of great importance in avoiding adverse effects and assuring complete removal of the ectoparasite, thereby avoiding the development of drug-resistance.

Outcome of an interventional program for scabies in an Indigenous community

OBJECTIVE

To implement an intervention program for reducing the prevalence of scabies in a large Northern Territory Aboriginal community.

DESIGN

Prospective, longitudinal screening, intervention and follow-up study.

PARTICIPANTS AND SETTING

All children aged 5 years and under in one of the largest Aboriginal communities in the Northern Territory, total population, approximately 2,200 (95% Indigenous).

MAIN OUTCOME MEASURES

A decrease in prevalence of scabies, infected scabies and non-scabies pyoderma over seven months.

RESULTS

The number of children aged 5 years and under screened intially and at the three follow-up screenings ranged from 201 to 242 (more than 98% of those eligible on each occasion). The prevalences of scabies, infected scabies and non-scabies pyoderma before intervention were 35%, 12% and 11%, respectively. At 6 weeks postintervention these had decreased to 3%, 1% and 4%, respectively; low prevalences were maintained at four and seven months.

CONCLUSIONS

This intervention, which was based on community motivation, involvement and control, successfully reduced the prevalence of scabies. Continuing community health education and regular screening will be crucial in controlling scabies. The methods and results of this study may be helpful in developing a coordinated program for all remote Aboriginal communities in the area.

Topical ivermectin: a new successful treatment for scabies

Ivermectin is the only one of the avermectins that has been widely used in humans, since it is recommended as the treatment of choice for onchocerciasis, a filariasis that produces "river blindness," a parasitic endemic infestation in countries of West Equatorial Africa and in some areas of Central and South America. Also, ivermectin has been used for treating human endo- and ectoparasites with effective results and with almost no side effects. To study the efficacy of ivermectin for scabies, which is very common in Colombia, a trial with this drug that could be easily administered, with fast application and high efficacy, was undertaken. For this purpose, six complete families with active scabies, consisting of 12 adults and 20 children ranging in age from 1 to 10 years, were treated with 1% ivermectin in a solution of propylene glycol applied topically to the affected skin. The dose employed was 400 microg/kg, repeated once the following week. All patients were cured, tolerated the medication well, and there were no side effects or signs of recurrence 2, 4, or 6 weeks after therapy. In addition to its efficacy, easy administration, and lack of side effects, ivermectin is a low-cost medication.

Pediculocidal and scabicidal properties of Lippia multiflora essential oil

The essential oil from the leaves of Lippia multiflora Moldenke (Verbenaceae) was tested for its pediculocidal and scabicidal activites against bodylice, headlice and scabies' mites. The 'knockdown' times obtained for bodylice and headlice using lippia oil preparations were comparatively shorter than those obtained using benzyl benzoate and Delvap Super, a brand of dichlorvos. The lethal effect of the lippia oil on headlice was increased when applied in an enclosed system that prevented volatilization of the oil while allowing maximum contact of the vapour with the headlice. A 20% v/v preparation of lippia oil applied to scabietic subjects for 5 consecutive days gave 100% cure compared with 87.5% cure obtained for benzyl benzoate preparation of the same concentration. The GC-MS analysis of oil revealed, among others, the presence of terpineol, alpha- and beta-pinene which are known to be lethal to body and headlice.

The use of ivermectin in controlling an outbreak of scabies in a prison

BACKGROUND

Ivermectin is a potentially useful treatment for scabies.

OBJECTIVES

We aimed to evaluate the efficacy of ivermectin in the treatment of scabies in an institutional environment.

METHODS

A single dose of ivermectin 150 microg kg-1 was given under supervision to 1153 prisoners in a prison in northern Tanzania where there was an outbreak of scabies.

RESULTS

Thirty per cent of the prisoners were cured after 1 week, 88% after 4 weeks and 95.5% after 8 weeks. Of 16 prisoners with crusted scabies, seven (44%) still had scabies after 8 weeks. Those who were not cured were then treated with 1% lindane lotion topically, as were the prison staff who had scabies. This regimen eradicated scabies from the prison for the next 2 years.

CONCLUSIONS

Ivermectin is an effective and safe treatment for scabies, particularly in a closed community, such as a prison, where it is easy to administer and avoids problems with compliance. It was of limited efficiency in crusted scabies as a single dose and we recommend that for such patients oral ivermectin is used in combination with a topical scabicide.

Topical therapies and medications in the pediatric patient

Topical medications and therapies are necessary for the proper management of skin diseases in children; however, physicians must be aware of the differences in percutaneous absorption and the risks for toxicity from topical medications, which are often unique to infants and children. Topical therapy must be individualized, and success often depends on proper vehicle selection, ease of application, and cost to patients and their families. Although many commercially available topical therapies are not FDA approved for use in children, recently enacted legislation has served to stimulate much-needed drug research in pediatric patients. New therapies on the horizon, such as tacrolimus, may prove to be equally efficacious and less toxic.

Management of endemic outbreaks of scabies with allethrin, permethrin, and ivermectin

BACKGROUND

At three residences for the elderly, recurrent scabies infestations became out of control. Due to the failure of repeated, nonsynchronized therapeutic efforts with conventional external anti-scabies treatments, an eradication program had to be developed. We describe a protocol for the management of outbreaks of scabies.

METHODS

According to the clinical examination and microscopically identified mites, all individuals of the population (IOP: patients, staff, and family members) were divided into two groups: (a) healthy and infested IOP; and (b) cases with crusted scabies. The first group was treated simultaneously once with external scabicides (allethrin or permethrin). All others were hospitalized and treated either with systemic ivermectin or with the latter in combination with permethrin.

RESULTS

In 252 IOP living in three residences for the elderly, clinical signs of scabies were reported in 91.5%, 78.5%, and 15.4% of the patients (age 55-97 years; mean, 80.5 years), 54.1%, 32.9%, and 16.6% of staff members, and in 7%, 3%, and 0% of family members. The infested IOP showed crusted scabies (index cases) in 5.3%, 5.0%, and 1.7%, common scabies in 43.1%, 36.7%, and 7.1%, and postscabiotic dermatitis in 10.3%, 7.6%, and 3.5%. In 99.2% of the synchronously treated IOP in group (a) (n = 240), the conventional treatment with permethrin cream 5% or allethrin spray was effective. Group (b) (n=12) received ivermectin (12 mg) once (n=5) or twice (n= 7) after an interval of 8 days. One index case received permethrin three times.

CONCLUSIONS

Outbreaks of scabies in populations of elderly people require special management for disease control. Synchronous treatment with external permethrin cream 5% or allethrin spray, including all IOP once, and close control offers a time-saving, cheap, and reliable method. Crusted scabies should be treated by oral administration of ivermectin once or twice after an interval of 8 days. Additional applications of permethrin and mechanical clearing of hyperkeratotic subungual areas shorten the course.

Scabies and pediculosis

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. They have been known since antiquity and are distributed worldwide. Clusters of infestation occur-for example, scabies affecting immunocompromised individuals or patients and staff in hospitals and nursing homes for the elderly, and pediculosis affecting schoolchildren or homeless people. Associations with other disorders are common: infections with human T-cell leukaemia/lymphoma virus I (HTLV-I) and HIV are associated with scabies, and trench fever and exanthematous typhus with pediculosis. Specific forms of scabies, including bullous scabies or localised crusted scabies, may be misdiagnosed. Moreover, definitive parasitic diagnosis can be difficult to obtain, and the value of new techniques remains to be confirmed. Difficulties in management have returned scabies and pediculosis to the limelight.

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.