Noninsecticidebased acaricides Benefits

Randomised studies comparing the non-insecticide antiscabies agent crotamiton with insecticide-based treatments were described above.

We found one trial (158 adults and children) comparing 25% benzyl benzoate with sulphur ointment (concentration of sulphur not given) in a community study in India.31 In this study patients were first scrubbed in a bath; the treatments were then applied three times in 24 hours (morning, night, next morning). Assessments were made at approximately 5-day intervals. No significant difference was found between the treatments regarding improvement of lesions at 9-10 days (benzyl benzoate 68/89 (76%) versus 45/69 (65%) with sulphur; RR 1-17, CI 1-0-1-4). At this time, if lesions remained the patients were treated again so that by 14-15 days improvement of symptoms in the benzyl benzoate group was 81/89 (91%) compared with 67/69 (97%) for sulphur (RR 0-94, CI 0-9-1-0), which was also not significantly different.

Non-controlled studies and case studies have indicated a variable effectiveness for both benzyl benzoate (20% emulsion,32 25% emulsion,14 25% cream33) and sulphur ointment (5%,35 6%,34 or 10%32,35). Activity of these acaricides is related to the concentration of active drug in the vehicle and the number of times they are applied. In general, benzyl benzoate appears to require a minimum of two applications and sulphur may require several applications over one week or longer.36

We found a single RCT evaluated by the systematic review comparing pork fat containing 1% salicylic acid and cold cream as ointment vehicles for delivery of sulphur.37 The numbers in this study were small (51 confirmed cases) and differences of efficacy could have been due to chance effects. Every participant applied the sulphur ointment on three consecutive nights and then again three days later. Evaluations were made on the tenth day after the last treatment. This study is more relevant for the side-effects observed, described below.

We found that other non-insecticide active materials have only been described in non-randomised studies and case series. One non-randomised study comparing 5% sulphur ointment, 1% lindane cream, 25% benzyl benzoate cream, 10% crotamiton lotion, and 0-2% nitrofurazone in a water-soluble ointment, found nitrofurazone was least effective, with a 70% cure rate.33 A case series of 20 patients using the same nitrofurazone ointment produced "complete clinical cure" in 80% of cases.38

Monosulfiram is now little used either as a liquid (25% before dilution for use) or a soap. Most studies are of poor quality and more than 50 years old, and more recent case studies show a high incidence of side-effects (see below). Thiabendazole has been used as a 5% and a 10% cream applied over several days. In one case series, 5/19 (26%) were still infested after 5% cream was used twice daily for 5 days. The remaining patients were cured after a further 5 days of treatment.39 Another case series, in which 10% cream was used, achieved 80% success after 5 days.40

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