Oral ivermectin to treat scabies: a comparison of two different regimens.

As Sarcoptes scabiei is becoming less sensitive to permethrin, clinicians have started to prescribe oral ivermectin (OI) as a first-line treatment. Guidelines suggest OI 200 µg kg-1 as two doses, 1 week apart. However, the black box of the ivermectin registered in Italy recommends a single dose. To compare these two regimens, we collected 71 cases of scabies and treated them according to this protocol [single-dose group (SDG)]. This population was compared to 68 patients who received two doses 1 week apart [double-dose group (DDG)]. Clearance of the disease was achieved in 98% of DDG patients. In the SDG, treatment was successful in only 58% of patients. This study confirms that the absence of a second intake of OI is one of the main predictors of treatment failure (P < 0.001), which may also increase the likelihood of emerging resistance in S. scabiei.