Variable response of crusted scabies to oral ivermectin: report on eight Egyptian patients

Background  Several reports have proved the efficacy of oral ivermectin in the treatment of crusted scabies. However, the response varied greatly between different studies.
Objective  The aim of this study was to evaluate the response of crusted scabies to oral ivermectin in eight Egyptian patients.
Patients and Methods  Eight patients with crusted scabies, diagnosed clinically and confirmed microscopically, were involved in this study. Patients received a single oral dose of ivermectin (200ug/kg) and re-examined at 2, 4, 6 and 8 weeks. A second dose of ivermectin was given in case of treatment failure at the end of the second week. A third dose of ivermectin, combined with permethrin 5% and salicylic acid 5% was given at the end of the fourth week for the nonresponders to the second dose.
Results  Two patients were completely cured after a single dose of ivermectin, 4 patients required a second dose at a 2-week interval to achieve cure and 2 patients cleared from scabies after the combined therapy. No recurrence was reported at the end of 8 weeks. An inverse relation was observed between the response to ivermectin and the severity of immunosuppression, crust thickness and mite burden.
Conclusion  Oral ivermectin is an effective alternative therapy for the treatment of crusted scabies. The response of crusted scabies to oral ivermectin is variable and combination therapy with topical scabicides and keratolytics seems to be the best choice.