Aussy et al reported risk factors for treatment failure for a patient with scabies. The authors are from University of Rouen Normandie.
Patient selection: infection with scabies in an outpatient
Frequency of treatment failure: 33%
Risk factors from multivariate analysis:
(1) use of a single dose of oral ivermectin (vs 2 or more; OR 6.6)
(2) use of topical benzyl benzoate alone (OR 3.5)
(3) failure to decontaminate furnishings (sofa, cushions, mattresses, car seats, etc with acaricides (OR 5.8)
(4) > 1 month between symptom onset (pruritis) and scabies treatment (OR 3.0)
(5) other known cases of scabies in the patient's "entourage" (OR 2.1)
Additional factors from the univariate analysis:
(1) intake of oral ivermectin with a meal (vs on an empty stomach)
(2) no written documents explaining treatment
