Overdiagnosis of scabies and overprescribing of scabies treatment in a scabies-endemic region

Aust J Rural Health. 2020 Aug;28(4):394-398. doi: 10.1111/ajr.12636. Epub 2020 Jun 23.

Abstract

Objective: To assess the objective evidence upon which diagnosis of scabies and subsequent prescription of permethrin cream or oral ivermectin is based at a tertiary referral hospital in the Northern Territory.

Design, setting and participants: A retrospective cohort study of inpatients who were prescribed permethrin or ivermectin between July and September 2017 at a single tertiary referral hospital. Eighty-eight inpatient admissions, belonging to 77 unique patients, were included. This list was generated with the hospital's electronic prescribing software.

Main outcome measures: Age, ethnicity, skin diagnosis on admission, which anti-scabies medications were prescribed, which concurrent medications were prescribed to treat a rash or pruritus, which differential or concurrent skin diagnoses were made, whether the dermatology department had seen the patient during their admission, and what evidence was documented as reason for diagnosis of scabies.

Results: In the cases in which scabies treatment was prescribed, less than one quarter had positive skin scrapings for scabies, and few had documentation of burrows, and documentation of a contact history combined with clinical lesions. Most cases met none of these diagnostic criteria. Very few were reviewed by the dermatology department as an inpatient.

Conclusions: There were likely high rates of diagnostic uncertainty among the cases in which scabies treatment was prescribed. It is possible that anti-scabies medications are being prescribed empirically in this hospital.

Keywords: Darwin; Northern Territory; dermatology department; ivermectin; permethrin.

MeSH terms

  • Adult
  • Ambulatory Care / statistics & numerical data
  • Drug Administration Schedule
  • Female
  • Humans
  • Inappropriate Prescribing / statistics & numerical data*
  • Insecticides / therapeutic use*
  • Male
  • Medical Overuse / statistics & numerical data*
  • Practice Guidelines as Topic
  • Retrospective Studies
  • Scabies / diagnosis*
  • Scabies / drug therapy*

Substances

  • Insecticides