Terapia della scabbia: Problema ricorrente. Motivi degli insuccessi e nuove proposte

The increased incidence of scabies infestation and resistance to the usual forms of treatment with increasingly frequent therapeutic failures have prompted dermatologists to look for more efficient forms of acaricide therapy which are more acceptable to patients. Although traditional galenical topical treatments, including polysulfurs, possess an undoubted antiparassitic action, they have an unpleasant odour, require numerous applications, frequently provoke local irritation and occasionally signs of systemic toxicity. Patient compliance is consequently scarce and there is a high risk of reinfestation. There are also other causes for the failure to treat human scabies: reinfestation after the end of treatment, paucisymptomatic forms with rare acari (difficult to find), possible resistance of acari to some antiparassitic compounds (DDT, benzyl benzoate) at atoxic concentrations, unmotivated patients or with immune deficiencies which are strongly receptive to parassitosis, patients who are sensitive to the active principle or substances contained in commercial preparations, and lastly inadequate information provided by the doctor on the correct treatment methods. New antiscabious molecules for topical and even systemic use have recently been introduced; among the first compounds to demonstrate their efficacy were permethrin (synthetic pyrethin) and bisbutylcarboethylene. Among the oral drugs which can eradicate the infestation are hivermectin and a few imidazolic antihelminthic agents: thiabendazole and flubendazole. As far as concern the systemic acaricides, further pharmacological, toxicological and controlled clinical studies are still required. They may prove beneficial above all in patients from whom a high level of compliance is requested or in whom adequate topical therapy is difficult to perform.