Sensitivity of Self-collected Skin Sampling for Scabies: a Pilot Study (SCRAPE)

In this cross-sectional diagnostic study, healthy adults aged 18 and older with suspected, clinical, or confirmed scabies will be recruited. The objective is to determine if the sensitivity of self-collected skin samples for scabies diagnosis is non-inferior to professional sampling, and compare the sensitivity and specificity of the polymerase chain reaction assay (PCR) versus microscopy.

Study Overview

• Status: Recruiting
• Conditions: Scabies
• Intervention / Treatment: Diagnostic test: Skin sampling

Detailed Description

Scabies infestations have significantly increased globally in the last 10-20 years, including a threefold rise in the Netherlands over the past decade. Diagnosing scabies is challenging due to varied symptoms and low sensitivity of current microscopic methods. New diagnostic techniques like PCR, which offer higher sensitivity, are being investigated. The feasibility of self-collected skin samples is being explored to reduce the burden on healthcare services and address issues like autonomy, stigma, and privacy.

In this cross-sectional diagnostic study, healthy adults aged 18 and older with suspected, clinical, or confirmed scabies will be included. Primary endpoint is the sensitivity of self-collected versus professional skin samples for diagnosing scabies. Secondary endpoints include sensitivity of skin scrapings and swabs, and the sensitivity and specificity of PCR versus microscopy.

Participants will self-collect skin samples during a standard care visit. The process may be slightly sensitive but not painful. There are no direct benefits beyond standard care.

• Study Type: Interventional
• Enrollment (Estimated): 144
• Phase: Early Phase 1

Contacts and Locations

• Study Contact: Name: Matthew MC McCall, PhD; Phone Number: +31 024 361 1111; Email: matthew.mccall@radboudumc.nl
• Study Contact Backup: Name: Saskia C van der Boor, PhD; Phone Number: +31 024 361 1111; Email: saskia.vanderboor@radboudumc.nl

Study Locations

• Netherlands
  • Gelderland
    • Nijmegen, Gelderland, Netherlands, 6525GA
      • Recruiting
      • Radboudumc
      • Contact: Matthew MC McCall, PhD; Phone Number: +31 024 361 1111; Email: matthew.mccall@radboudumc.nl
      • Contact: Saskia C van der Boor, PhD; Phone Number: +31 024 361 1111; Email: saskia.vanderboor@radboudumc.nl
      • Sub-Investigator: Suzanne Roos-Soethoudt, MSc
      • Principal Investigator: Stijn Raven, PhD
      • Principal Investigator: Jeannine Hautvast, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 18 years or older
• Have either suspected scabies, clinical scabies or confirmed scabies (see table 1)
• Providing informed consent (IC)

Exclusion Criteria:

• Individuals not speaking or understanding the Dutch or English language.
• Individuals who have been diagnosed with scabies in the last six weeks and had started treatment.
• Individuals who have used ivermectin for other diagnoses than scabies in the last six weeks.
• Individuals younger than 18 years.
• Individuals with immunosuppressive conditions (see appendix A).
• Any other condition, finding or situation which, in the opinion of the investigator, may significantly increase the risk to the individual because of participation in the study, affect the ability of the individual to participate in the study or impair interpretation of the study data.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group; All participants will be asked to perform self-sampling and irrespective of the result will receive current standard-of-care from their health care provider for their suspected scabies.	Diagnostic test: Skin sampling; All individuals will self-collect skin samples and swabs and fill in a questionnaire. Subsequently, all individuals will see a professional. The professional will collect skin samples and swabs as well.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The sensitivity of self-collected skin samples for diagnosing scabies	The proportion of self-collected samples collected at the enrolment visit that are tested positive, divided by the total number of participants adjudged retrospectively to have had scabies at their enrolment visit, based on a composite clinical diagnosis.	through study completion, an average of one year
The sensitivity of professionally-collected skin samples for diagnosing scabies	The proportion of professionally-collected samples collected at the enrolment visit that are tested positive, divided by the total number of participants adjudged retrospectively to have had scabies at their enrolment visit, based on a composite clinical diagnosis.	through study completion, an average of one year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The sensitivity of skin scrapings for diagnosing scabies	The proportion of skin scrapings at their enrolment visit (whether professionally or self-collected) that are tested positive by PCR, divided by the total number of participants adjudged retrospectively to have had scabies at baseline, based on a composite clinical diagnosis.	through study completion, an average of one year
The sensitivity of skin swabs for diagnosing scabies	The proportion of skin swabs at their enrolment visit (whether professionally or self-collected) that are tested positive by PCR, divided by the total number of participants adjudged retrospectively to have had scabies at baseline, based on a composite clinical diagnosis.	through study completion, an average of one year
The sensitivity and specificity of PCR on skin scraping for diagnosing active scabies infection	The proportion of participants adjudged to have had scabies at their enrolment visit (based on a retrospective composite clinical diagnosis), whose skin scraping at their enrolment visit (whether professionally or self-collected) are tested positive for scabies by PCR, and the proportion of participants adjudged retrospectively to have not had scabies at their enrolment visit whose skin scrapings are tested negative for scabies by PCR.	through study completion
The sensitivity and specificity of microscopy on skin scraping for diagnosing active scabies infection	The proportion of participants adjudged to have had scabies at their enrolment visit (based on a retrospective composite clinical diagnosis), whose skin scraping at their enrolment visit (whether professionally or self-collected) are tested positive for scabies by microscopy, and the proportion of participants adjudged retrospectively to have not had scabies at their enrolment visit whose skin scrapings are tested negative* for scabies by microscopy.	through study completion, an average of one year

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of participants whose self-sampling location is judged appropriate	Assessed by a professional at T=0 [adequate/non-adequate]	through study completion, an average of one year
Motivation for self-collection of skin samples for scabies diagnostics	Motivation is assessed by items on the questionnaire related to the motivation for self-collection of skin samples for scabies diagnostics, along with the associated facilitators and barriers.	through study completion, an average of one year
Demographic, clinical and epidemiological factors which influence the sensitivity of self-collected skin samples for scabies diagnosis.	Age, gender, highest level of education, signs/symptoms, living situation, skin color. source of transmission and transmission mode.	through study completion, an average of one year

Collaborators and Investigators

• Sponsor: Radboud University Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): August 21, 2024
• Primary Completion (Estimated): June 1, 2025
• Study Completion (Estimated): June 1, 2025

Study Registration Dates

• First Submitted: July 26, 2024
• First Submitted That Met QC Criteria: August 6, 2024
• First Posted (Actual): August 9, 2024

Study Record Updates

• Last Update Posted (Actual): August 9, 2024
• Last Update Submitted That Met QC Criteria: August 6, 2024
• Last Verified: July 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Skin Diseases; Infections; Parasitic Diseases; Ectoparasitic Infestations; Skin Diseases, Parasitic; Skin Diseases, Infectious; Mite Infestations; Scabies
• Other Study ID Numbers: NL86424.091.24

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No