Scabies Management Outcomes: Identification of Risk Factors for Treatment Success or Failure

Abstract

Introduction: Scabies is a parasitic infectious skin disease classified as a neglected tropical disease by the World Health Organization in 2017. Currently, it is becoming a major challenge in high-income countries, with rapidly rising incidence and increasing reports about treatment failure. Objectives: Factors that are associated with treatment failure or success were evaluated. Methods: This non-interventional prospective observational study was conducted as a questionnaire survey at the Department of Dermatology and Venereology of the University of Freiburg from January to November 2023. Patients that still suffered from scabies 2–6 weeks after medical treatment were classified as “failure”; those who were free of scabies belonged to the success group. Results: Of 102 participants, with a mean age of 34.4 ± 17.3 years (male: 60.4%), 77 (75.5%) were assigned to the success and 25 (24.5%) to the failure group. A larger proportion of the latter was clinically more severely affected, applied permethrin monotherapy, did not undertake special decontamination measures, but used alcohol as a disinfectant. Treatment success was associated with an additional systemic treatment, a repeated intake of ivermectin, and intensified decontamination measures such as storage of clothes in plastic bags for four days or vacuum cleaning of car seats. Conclusions: Our findings indicate that a consistent second-dose administration of ivermectin and refraining from permethrin monotherapy may be advisable.

Keywords

• ivermectin
• permethrin
• scabies
• treatment failure
• Treatment outcome
• Drug resistance