Background: This article describes a scabies outbreak at a boarding school where failure of the first-line therapy was suspected.
Case presentation: A group of five students, two of whom were room-mates, presented with a varying degree of pruritic papular rash. Repeated treatments with permethrin monitored by the school nurse, in conjunction with a rigorous hygiene regimen, proved to be ineffective. Eventually all five students were prescribed a combination therapy consisting of permethrin and ivermectin. This treatment proved effective in all five students. Despite closely monitored treatment, monotherapy with permethrin failed in all five patients. We discuss whether the lack of response was due to failed application, inability to rid the home environment of mites, reinfection by unidentified infected individuals or increased tolerance to permethrin.
Interpretation: Repeated therapeutic failure when permethrin was used under controlled conditions and documented mechanisms for increased tolerance may indicate the last possibility. We therefore call for additional research on this topic.