Treatment and Control of Scabies
Treatment and Control of Scabies
An important factor that can confound assessment of treatment outcome is that the residual 'allergic' immune responses to mites can persist, or even increase, for weeks after mites have been killed. This persistence of pruritus, possibly resulting in further excoriation, is probably the single most important reason for perceived treatment failure, and can be a great source of frustration for patients. Thus, it is most important that this be clearly explained to the patient, and that they be advised that apart from symptomatic treatment they should avoid repeated application or ingestion of antiparasitic therapy, the former potentially exacerbating skin irritation. Treatment with antihistamines is a useful adjunct and may provide symptomatic relief during this 'mite clearance' period. Topical or oral corticosteroid therapy however should be used with caution due to the increased risk of masking treatment failure and predisposing to crusted scabies.
Treatment failures can be due to incorrect application of acaricide, reinfestation from untreated contacts, or mite resistance to acaricides. Although the third is commonly blamed and is of growing concern (see below), the first two scenarios probably account for the majority of reported treatment failures in scabies.
General Considerations When Assessing Treatment Response
An important factor that can confound assessment of treatment outcome is that the residual 'allergic' immune responses to mites can persist, or even increase, for weeks after mites have been killed. This persistence of pruritus, possibly resulting in further excoriation, is probably the single most important reason for perceived treatment failure, and can be a great source of frustration for patients. Thus, it is most important that this be clearly explained to the patient, and that they be advised that apart from symptomatic treatment they should avoid repeated application or ingestion of antiparasitic therapy, the former potentially exacerbating skin irritation. Treatment with antihistamines is a useful adjunct and may provide symptomatic relief during this 'mite clearance' period. Topical or oral corticosteroid therapy however should be used with caution due to the increased risk of masking treatment failure and predisposing to crusted scabies.
Treatment failures can be due to incorrect application of acaricide, reinfestation from untreated contacts, or mite resistance to acaricides. Although the third is commonly blamed and is of growing concern (see below), the first two scenarios probably account for the majority of reported treatment failures in scabies.
