The treatment of scabies with ivermectin

BACKGROUND

Ivermectin is an anthelmintic agent that has been a safe, effective treatment for onchocerciasis (river blindness) when given in a single oral dose of 150 to 200 micrograms per kilogram of body weight. Anecdotal reports of improvement in patients who suffered from infestation with the mite Sarcoptes scabiei suggest that the ectoparasitic disease scabies might be treated with ivermectin.

METHODS

We conducted an open-label study in which ivermectin was administered in a single oral dose of 200 micrograms per kilogram to 11 otherwise healthy patients with scabies and to 11 patients with scabies who were also infected with the human immunodeficiency virus (HIV), 7 of whom had the acquired immunodeficiency syndrome. All patients received a full physical and dermatologic examination; scrapings from the skin of all patients tested positive for scabies. Patients were reexamined two and four weeks after treatment, when the scrapings for scabies were repeated. The patients used no other scabicides during the 30 days before ivermectin treatment or during the 4-week study period.

RESULTS

None of the 11 otherwise healthy patients had evidence of scabies four weeks after a single dose of ivermectin. Of the 11 HIV-infected patients, 2 had < or = 10 scabies lesions before treatment, 3 had 11 to 49 lesions, 4 had > or = 50 lesions, and 2 had heavily crusted skin lesions. In eight of the patients the scabies was cured after a single dose of ivermectin. Two patients received a second dose two weeks after the first. Ten of the 11 patients with HIV infection (91 percent) had no evidence of scabies four weeks after their first treatment with ivermectin.

CONCLUSIONS

The anthelmintic agent ivermectin, given in a single oral dose, is an effective treatment for scabies in otherwise healthy patients and in many patients with HIV infection.

Aging, acculturation, salt intake, and hypertension in the Kuna of Panama

The indigenous Kuna who live on islands in the Panamanian Caribbean were among the first communities described with little age-related rise in blood pressure or hypertension. Our goals in this study were to ascertain whether isolated island-dwelling Kuna continue to show this pattern, whether migration to Panama City and its environs changed the patterns, and whether the island-dwelling Kuna have maintained their normal blood pressure levels despite partial acculturation, reflected in an increased salt intake. We enrolled 316 Kuna participants who ranged in age from 18 to 82 years. In 50, homogeneity was confirmed by documentation of an O+ blood group. In 92 island dwellers, diastolic hypertension was not identified and blood pressure levels were as low in volunteers over 60 years of age as in those between 20 and 30 years of age. In Panama City, conversely, hypertension prevalence was 10.7% and exceeded 45% in those over 60 years of age (P < .01), blood pressure levels were higher in the elderly, and there was a statistically significant positive relationship between age and blood pressure (P < .01). In Kuna Nega, a Panama City suburb designed to maintain a traditional Kuna lifestyle but with access to the city, all findings were intermediate. Sodium intake and excretion assessed in 50 island-dwelling Kuna averaged 135 +/- 15 mEq/g creatinine per 24 hours, exceeding substantially other communities free of hypertension and an age-related rise in blood pressure. Despite partial acculturation, the island-dwelling Kuna Indians are protected from hypertension and thus provide an attractive population for examining alternative mechanisms.

Community control of scabies: a model based on use of permethrin cream

For 18 years treatment with lindane or crotamiton products has failed to stem the epidemic of scabies among the Kuna Indians in the San Blas islands of the Republic of Panama. Permethrin 5% cream was introduced as the only treatment in a programme to control scabies on an island of 756 inhabitants and involving workers recruited locally. Prevalence fell from 33% to less than 1% after every person was treated. As long as continued surveillance and treatment of newly introduced cases was maintained, prevalence of scabies remained below 1.5% for over 3 years. When supply of medication was interrupted for 3 weeks, prevalence rose to 3.6%. When control was lost after the US invasion of Panama, prevalence rose to 12% within 3 months. Bacterial skin infections decreased dramatically when scabies was controlled. Permethrin is safe and effective even in areas where this disease has become resistant to lindane.

Genetic epidemiology of Sarcoptes scabiei (Acari: Sarcoptidae) in northern Australia

Utilising three hypervariable microsatellite markers we have previously shown that scabies mites on people are genetically distinct from those on dogs in sympatric populations in northern Australia. This had important ramifications on the formulation of public health control policies. In contrast phylogenetic analyses using mitochondrial markers on scabies mites infecting multiple animal hosts elsewhere in the world could not differentiate any genetic variation between mite haplotype and host species. Here we further analyse the intra-specific relationship of Sarcoptes scabiei var. hominis with S. scabiei var. canis by using both mitochondrial DNA and an expanded nuclear microsatellite marker system. Phylogenetic studies using sequences from the mitochondrial genes coding for 16S rRNA and Cytochrome Oxidase subunit I demonstrated significant relationships between S. scabiei MtDNA haplotypes, host species and geographical location. Multi-locus genotyping using 15 microsatellite markers substantiated previous data that gene flow between scabies mite populations on human and dog hosts is extremely rare in northern Australia. These data clearly support our previous contention that control programs for human scabies in endemic areas with sympatric S. scabiei var. hominis and var. canis populations must focus on human-to-human transmission. The genetic division of dog and human derived scabies mites also has important implications in vaccine and diagnostic test development as well as the emergence and monitoring of drug resistance in S. scabiei in northern Australia.

Genetically distinct dog-derived and human-derived Sarcoptes scabiei in scabies-endemic communities in northern Australia

Overcrowding is a significant factor contributing to endemic infection with Sarcoptes scabiei in human and animal populations. However, since scabies mites from different host species are indistinguishable morphologically, it is unclear whether people can be infected from scabies-infested animals. Molecular fingerprinting was done using three S. scabiei-specific single locus hypervariable microsatellite markers, with a combined total of 70 known alleles. Multilocus analysis of 712 scabies mites from human and dog hosts in Ohio, Panama and Aboriginal communities in northern Australia now shows that genotypes of dog-derived and human-derived scabies cluster by host species rather than by geographic location. Because of the apparent genetic separation between human scabies and dog scabies, control programs for human scabies in endemic areas do not require resources directed against zoonotic infection from dogs.

Comparison of crotamiton 10% cream (Eurax) and permethrin 5% cream (Elimite) for the treatment of scabies in children

Permethrin 5% cream (Elimite) was approved as a treatment for scabies by the U.S. Food and Drug Administration in September 1989. In a double-blinded, randomized study, it was compared with crotamiton 10% cream (Eurax) for the treatment of scabies in children 2 months to 5 years of age. Two weeks after a single overnight treatment, 14 (30%) of 47 children were cured with permethrin 5% cream, in contrast to only 6 of 47 (13%) of subjects treated with Eurax. Four weeks after treatment the figures were 89% and 60% cured for the two agents, respectively. In 10 of the 19 patients whose treatment failed, the condition became worse after therapy. The difference in efficacy in favor of permethrin was significant (P = 0.002). That agent also demonstrated greater effectiveness in reducing pruritus and secondary bacterial infections. Elimite offers a safe, efficacious, and cosmetically elegant alternative to Eurax in the treatment of scabies in children.

Permethrin 1% creme rinse for the treatment of Pediculus humanus var capitis infestation

Permethrin 1% creme rinse (NIX) was tested as a treatment for Pediculus humanus var capitis (head lice) in a placebo-controlled, double-blinded, randomized study. As a positive control, a third arm of the study included nonrandomized, but investigator-blinded, treatment with 1% lindane shampoo (Kwell). At 14 days after treatment, 97% of patients treated with permethrin were free of lice compared to 6% of placebo-treated patients (P less than 0.001) and 43% of the lindane-treated group. Permethrin was 70% ovicidal compared to 14% for placebo (P less than 0.001) and 45% for lindane. No adverse experiences were noted during this study. Permethrin 1% demonstrated high pediculicidal and ovicidal activities, which in combination with its low mammalian toxicity, residual activity, and cosmetic properties, make it an excellent treatment for pediculosis capitis.

Permethrin 5% dermal cream: a new treatment for scabies

Permethrin 5% dermal cream (Burroughs Wellcome Co.) was compared in an investigator-blinded, randomized study against lindane 1% lotion (Kwell) for the treatment of microscopically confirmed scabies. Eleven of twenty-three patients treated with permethrin cream were cured in 2 weeks (48%). Only two patients had scabies 1 month following a single treatment with this product, giving a cure rate of 91%. One of these two patients was considered to have a reinfestation. Only three of twenty-three (13%) patients treated with 1% lindane lotion (Kwell) were free of scabies 2 weeks after a single treatment and fifteen of twenty-three (65%) were cured at 1 month. The unusually high percentage of treatment failures (35%) following lindane therapy may have been related to extensive use of this agent for head lice and scabies in this village during the preceding 5 years. The higher cure rate at 1 month seen with permethrin cream was significant (p less than 0.025). Permethrin 5% dermal cream offers a new, cosmetically elegant alternative to lindane therapy and was effective in a community in which lindane demonstrated an unacceptable level of treatment failures.

Seabather's eruption. Clinical, histologic, and immunologic features

BACKGROUND

Seabather's eruption (SE) is a highly pruritic eruption under swimwear that occurs after bathing in the ocean. Its cause has been unknown. Few data have been collected since the classic description by Sams in 1949.

OBJECTIVE

Our purpose was to describe the clinical and histopathologic findings in SE and to confirm the cause.

METHODS

Patients with a pruritic eruption that developed after swimming were seen within 1 week of onset. Skin biopsy specimens and sera were obtained in selected cases. Water samples taken from areas of active SE outbreaks were examined for a causative organism. Sera were tested by enzyme-linked immunosorbent assay for reactivity to this organism.

RESULTS

In southeast Florida, during a 4-month period, 70 patients with SE were seen. Inflammatory papules and pruritus were noted within hours of exposure. Eruptions were maximal in areas covered by a bathing suit. Children were more likely than adults to have systemic symptoms. The average duration of the eruption and pruritus was 12.5 days, with recurrences in 4.3% of patients. Histopathologic examination revealed a superficial and deep perivascular and interstitial infiltrate consisting of lymphocytes, neutrophils, and eosinophils. Water samples contained many cnidarian larvae, later grown to maturity and identified as Linuche unguiculata (thimble jellyfish). Enzyme-linked immunosorbent assay demonstrated in patients' sera high IgG levels specific for L. unguiculata.

CONCLUSION

SE is a severely pruritic marine dermatosis that resolves spontaneously within 2 weeks. Therapy is symptomatic but often ineffective. Sera from affected persons showed specific reactivity to L. unguiculata.

A comparative trial of three treatment schedules for the eradication of scabies

A trial of three treatment schedules, consisting of 1% gamma benzene hexachloride (GBH) lotion applied head to toe and left on the body for 2, 6, or 12 to 24 hours was conducted on an island of 2,076 persons, approximately 70% of whom had clinical evidence of scabies. The island is situated off the north coast of the Republic of Panama. Examination at 1 month after therapy showed that both the 6-hour and 12- to 24-hour cure rate was high (96% and 98%). There was a significantly lower cure rate in the 2-hour group, in which only 82% were cured. Eleven to twelve percent of the subjects became infested in all groups, presumably due to contact with untreated persons with scabies on the island. A single 6-hour application of 1% GBH lotion appears to be adequate therapy for scabies if properly applied. The entire population at risk should be treated at the same time if possible to reduce or eliminate the risk of infestation. No adverse reactions to 1% GBH lotion were observed.

Age, renal perfusion and function in island-dwelling indigenous Kuna Amerinds of Panama

BACKGROUND/AIMS

Among possible contributors to a progressive fall in renal perfusion and function with increasing age, some hypotheses have invoked the rise in blood pressure that occurs with age, and a high-protein diet typical of urban cultures. Kuna Amerinds residing in isolated islands off the Panamanian Coast have a very low protein intake and show no tendency for blood pressure to rise with age, thus providing an opportunity to test these hypotheses.

METHODS

We measured renal plasma flow and glomerular filtration rate (PAH and inulin clearance) in 16 Kuna Indians ranging in age from 18 to 86 years (51 +/- 6 years) who have resided on Ailigandi, an isolated Panamanian island for all of their lives. Inulin and PAH were infused with a battery-driven pump for 60 min, and a metabolic clearance rate used to calculate inulin and PAH clearance. For comparison, we employed identical techniques in 29 residents of Boston, ranging in age from 19 to 79 years (52 +/- 4 years), all normotensive and free of disease or medication use. Twenty-four were Caucasian.

RESULTS

The Bostonian controls showed the anticipated fall in PAH clearance with age (y = 806 - 4.9 x; r = -0.82; f = 38.0; p < 0.0001). Our hypothesis was that the absence of a blood pressure rise with age and the low protein intake would flatten the slope relating renal perfusion to Kuna age. Our finding was a numerically steeper slope relating age and renal plasma flow in the Kuna (y = 936 - 6.48x; r = -0.81; p < 0.001). Filtration fraction rose with age in both populations, and again the rise was steeper in the Kuna. GFR in the Kuna, on the other hand, was very much higher at any age (139 +/- 4 ml/min/1.73 m2) than in Bostonians (112 +/- 3 ml/min/1.73 m2; p < 0.001).

CONCLUSION

The findings are not in accord with the hypothesis that age-related changes in renal perfusion and glomerular filtration rate reflect an important contribution from blood pressure rise and a high protein intake, typical of modern, urban life.

Fatal Aeromonas hydrophila infection of the skin

A 62-year-old woman developed a fatal Aeromonas hydrophila infection of the skin after dropping a crab trap on her leg. The area surrounding the punctures was erythematous and had several flaccid bullae. A biopsy specimen of the involved skin showed necrosis and suppuration in the dermis and subcutaneous fat. The A hydrophila sepsis resolved after treatment with gentamicin, but the patient developed secondary wound infections and died three months after injury.

Eradication of scabies with a single treatment schedule

A single application (16 to 20 hours) of 1% gamma benzene hexachloride (GBH) lotion, when applied to a total island population of 178 persons in which seventy-four clinically had scabies, resulted in a cure rate of over 98%. Re-examination of the population at 10 and 21 weeks revealed only one remaining individual still having scabies. On a neighboring island, only those with clinical evidence of scabies were treated (140 persons). Applications of 1% GBH lotion were applied with the same methods used on the first island. When the population was re-examined at 10 weeks, the prevalence of scabies was reduced by only 50%. Successful eradication of scabies from a population should include treatment of all contacts, whether clinically infected or not. Treatment of the entire population at risk at one time is preferable. Coexistent pyoderma should be treated, and a second treatment for scabies may be needed when the pyoderma has cleared.

Treatment of HIV-related scabies with emphasis on the efficacy of ivermectin

Since the mid-1980s, worldwide reports confirm that scabies in individuals infected with the human immunodeficiency virus (HIV) result in a wide range of-clinical manifestations which differ from those seen in immunocompetent patients. There is also general agreement that HIV-related scabies is more difficult to treat. Oral ivermectin has been shown in several countries to be a safe and effective therapy. In otherwise healthy persons, one dose of 200 microg/kg is usually curative. In HIV-related scabies, one treatment may be curative but repeated doses may be required. Crusted scabies in these individual requires a combination of oral ivermectin, total body treatments with 5% permethrin cream, and keratolytic agents to hasten removal of crusts.

Identification of host DNA by amplified fragment length polymorphism analysis: preliminary analysis of human crab louse (Anoplura: Pediculidae) excreta

The ability to identify individual hosts of hematophagous arthropods via bloodmeal analyses is a continuing pursuit in both medical and forensic entomology. Characterization of human DNA from blood-feeding arthropods has been advanced substantially by preparation techniques, such as the polymerase chain reaction (PCR). Successful application of amplified fragment length polymorphism (AMP-FLP) analysis to excreta obtained from adult crab lice, Pthirus pubis (L.), fed on human volunteers is reported herein. Human DNA derived from crab louse excreta was typed successfully for two human DNA genetic markers, D1S80 and HUMTH01. Although preliminary, these results illustrate the ability of AMP-FLP analyses to provide individual human locus characterizations from desiccated arthropod excrement.

Skin infections in eastern Panama. Survey of two representative communities

A skin infection survey of 1,084 people was carried out in two jungle villages in eastern Panama. Bacterial pyoderma was the most prevalent infection, affecting 25% of boys, 15% of girls, and 11% of those over 10 years of age. Streptococcus pyogenes and Staphylococcus aureus were recovered from 84% of pyodermas cultured. Nearly 60% of the cutaneous staphylococcal isolates were resistant to penicillin. Hippelates flies were seen feeding on purulent skin lesions and may have been important in transmission. Scabies, ringworm, candidiasis, and cutaneous leishmaniasis were in comparison with pyoderma involving less than 1% of the population each. All of the ringworm infections were caused by Trichophyton rubrum.

A community outbreak of scabies

An elementary school in Broward County, Florida, reported an outbreak of scabies in January and February 1975. Investigation identified 23 cases of scabies in schoolchildren, with at least two cases in each grade. The first case had appeared as early as July 1974, but most occurred after December. There was little contact between students in different grades; most transmission was found to have taken place within families and in the community. An additional 28 cases were found in families and contacts; altogether, 51 cases in 24 families were identified on clinical or historical grounds. Infestation was more frequent in children who exchanged clothes with friends or relatives and in those who, on occasion, spent the night with other children.

Recovery of Staphylococcus aureus from multiple body sites in menstruating women

Because we suspected the number of women harboring Staphylococcus aureus perivaginally to be higher than previously reported, we undertook an examination of normal, healthy volunteers. Of 97 young women, 26% yielded S. aureus from the external labia at the time of menstruation. Toxin associated with toxic shock syndrome was recovered from 5 of 25 subjects with positive genital cultures. Approximately one-half of the women with positive genital cultures yielded positive cultures from the posterior cervical fornix. These 12 women with positive vaginal cultures formed a distinct subgroup that was characterized by positive labial and tampon cultures, higher incidence of previous streptococcal infections, and more frequent vaginal insertion of their own fingers or those of a partner. Tampons were used by all but one woman in the group with positive labial cultures and all but one woman in the group with positive vaginal cultures. We concluded that the presence of S. aureus in the vagina involves mechanisms other than the use of tampons. Insertion of fingers and perhaps some aspect of immunological status appear to play a role.