Current treatments for scabies

Scabies is a frequent interhuman ectoparasitic infection. Several treatments are available worldwide. There are local treatments: synthetic pyrethrins, benzyl benzoate, lindane, crotamiton. Recently a few studies were published concerning ivermectin, systemic antiparasitic agent use in onchocercosis treatment. We reviewed the literature with an evidence‐based medicine method. We attempt to answer two questions in particular: what is the treatment of choice for common scabies in a patient otherwise in good health? What is the role of systemic ivermectin? We also report specific situations. Among local treatments, studies are heterogeneous according to products, countries, group of treated patients, with or without contact subjects, and the method of treatment application. There are very few high proof‐level controlled studies. In France, a combination of benzyl benzoate 10% and sulfiram 2% is used most, according to professional consensus. The most studied product is the cream permethrin 5%, available in the USA and UK. Its efficacy seems slightly superior to lindane and less toxic. It is more efficient than crotamiton. There is no study comparing benzyl benzoate and permethrin. Concerning systemic ivermectin, five controlled studies showed its efficiency in common scabies. But its relative efficiency over local treatment has not been established. A few open studies showed its efficacy in institutional epidemic, profuse scabies and in HIV‐positive patients. Local treatment of choice in common scabies remains to be determined among the four principal molecules. There is no study comparing permethrin or esdepallethrin to benzyl benzoate. In what cases should we prescribe crotamiton or lindane? Indication of ivermectin seems proved in common scabies and probably for HIV‐positive patients. It remains to be determined if it should be prescribed in the first instance, be double or triple, be associated or not with local treatment. In case of keratotic scabies, ivermectin seems interesting with two applications within 1 week, and should be associated with local treatment (duration remains to be defined). Ivermectin is probably useful in institutional epidemic, and therapeutic attitude remains to be defined. Ivermectin seems to have little or no risk. Treatment must be adapted case‐by‐case, according to feasibility. It is still important to treat contacts, and modality of this treatment remains to be specified.     

Pharmacokinetics of ivermectin applied topically by whole‐body bathing method in healthy volunteers

As a novel administration method of ivermectin (IVM) for scabies treatment, we proposed a “whole‐body bathing method (WBBM)”. In this method, the patients would bathe themselves in a bathing fluid containing IVM at an effective concentration. Previously, we demonstrated that WBBM could deliver IVM to the skin but not to the plasma in rats. In the present study, to assess the clinical validity of the method an arm bathing examination (first trial) and a whole‐body bathing examination (second trial) were conducted in healthy volunteers. In both the first and second trials, after bathing in fluid containing IVM, the exposure in the stratum corneum was higher compared with that after taking IVM p.o. as reported previously. IVM was not detected in plasma at any sampling point after the whole‐body bathing in the second trial. Furthermore no serious adverse events were found. These results in both trials suggest that WBBM can deliver IVM to the human stratum corneum without systemic exposure or serious adverse effects in healthy volunteers, and at concentrations that would be adequate for scabies treatment.     

Guideline for the diagnosis and treatment of scabies in Japan (third edition)

In the current work, we present our new guideline for the diagnosis and treatment of scabies which we, the Executive Committee convened by the Japanese Dermatological Association, developed to ensure proper diagnosis and treatment of scabies in Japan. Approval of phenothrin topical use under the National Health Insurance in August 2014 led to this action. Permethrin, a topical anti‐scabietic medication belonging to the same pyrethroid group as phenothrin, is already in use worldwide. In this guideline, we introduce criteria for a proper diagnosis of scabies, treatment algorithm for common and crusted (hyperkeratotic) scabies, and prevention. The major change from our second edition is the treatment algorithm. As phenothrin is now available, the first‐line therapy for common scabies is either topical phenothrin lotion or oral ivermectin. The second‐line option for topical treatment is sulfur‐containing ointments, crotamiton cream or benzyl benzoate lotion. γ‐Benzene hexachloride ointment is no longer provided for clinical use. In an immunosuppressed patient, the treatment option is still the same, but with close follow up. If the symptoms persist, diagnosis and treatment must be reassessed. For hyperkeratotic scabies and nail scabies, removal of thick crust, cutting of nails and occlusive dressing are additionally required. The safety and effectiveness of combined treatment with topical and oral medications are not yet confirmed. Further assessment is needed. In addition to appropriate treatment, it is essential to educate patients and health‐care workers and to conduct epidemiological studies to prevent further spread of the disease through effectively utilizing available resources including manpower, finance, logistics and time.     

3%伊维菌素粉剂防治白蚁的效果研究

目的了解3%伊维菌素粉剂对白蚁的防治效果,为防治白蚁提供新的灭治药物。方法在室内通过中毒个体转移法测定药剂毒性在个体间的传递效果;在野外通过对活动的白蚁喷粉测定药剂的灭巢效果。结果 3%伊维菌素粉剂的毒性可通过接触在白蚁个体间传递1次;在野外应用3%伊维菌素粉剂20～30 g可杀灭散白蚁巢群,应用30～50 g可杀灭乳白蚁巢群。结论 3%伊维菌素粉剂可替代灭蚁灵通过喷粉方式防治白蚁。     

Treatment of human Mansonella streptocerca infection with ivermectin

We studied the short‐term effects of a single dose of 150 μg/kg body weight ivermectin on Mansonella streptocerca in an area endemic for streptocerciasis, but not for onchocerciasis, in western Uganda. Six and 12 days after treatment no microfilariae (mf) were found in the skin of 53 out of 96 mf carriers living in 3 villages, and the geometric means of the mf densities of remaining mf carriers were only 33–40% of pretreatment levels. This reduction of mf density was highly significant ( P <0.0001). Immunohistological examination of skin biopsies showed degenerated and disintegrating mf surrounded by activated eosinophils (positive for activated cationic protein), macrophages, and neutrophils (positive for myeloperoxidase and defensin) on day 6 after treatment. Remarkable was the invasion of young, L1 protein‐positive macrophages and the release of neutrophil defensin as signs of acute inflammation. We conclude that ivermectin has a strong microfilaricidal activity against M. streptocerca Common adverse effects were increased pruritus and acute papular dermatitis in 45% of 86 mf carriers on day 6 after treatment. No serious adverse side‐effects were noticed in about 700 treated persons.     

Short communication: impact of long-term (14 years) bi-annual ivermectin treatment on Wuchereria bancrofti microfilaraemia

Ivermectin has been and continues to be extensively used to control onchocerciasis in areas of hyper and mesoendemicity within the African Programme of Onchocerciasis Control. As programmes to eliminate lymphatic filariasis (LF) caused by Wuchereria bancrofti expand, areas of coendemicity with onchocerciasis will be incorporated into LF programmes. This study reports that in villages which were hyperendemic for onchocerciasis after some 14 years of treatment with ivermectin, no W. bancrofti could be detected in a population of 1210 individuals whilst in adjacent villages a prevalence of around 3% was found. Despite the long period of ivermectin treatment Mansonella perstans did not appear to respond to ivermectin in this setting.     

Treatment strategies in controlling strongyloidiasis

Strongyloidiasis is an intestinal parasite infection caused by Strongyloides stercoralis. Spontaneous cure cannot be expected due to the unique life cycle of the parasite, termed autoinfection. The disease occurs worldwide, but especially in tropical and subtropical regions. Serious clinical problems with complications and refractory strongyloidiasis are observed, especially in immunocompromised patients, such as those infected with human T cell leukaemia virus Type 1 (HTLV-1) or HIV, or corticosteroid-treated patients. Thiabendazole is effective against S. stercoralis infection; however, serious side effects have been reported. Recently, ivermectin, which has been introduced for the treatment of human onchocerciasis, has been reported to be effective against strongyloidiasis, without serious side effects. The interval of administration is important for treatment, because if autoinfective migrating larvae are not eradicated, S. stercoralis will resume its life cycle and multiply again. To evaluate the results of treatment of S. stercoralis, stool examinations and S. stercoralis-specific antibody titres should be examined for at least 1 or 2 years if possible. This article provides a review of treatments and methods of evaluation of patients infected with S. stercoralis.