Scabies
Conditions
Brief summary
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.
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.
Interventions
DIAGNOSTIC_TESTSkin 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.
Sponsors
Radboud University Medical Center
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Intervention model description
The study design is cross-sectional in terms of the diagnostic process, which aims to determine the presence of scabies in an individual at a specific point in time. All participants will undergo the same diagnostic procedures.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The sensitivity of self-collected skin samples for diagnosing scabies | through study completion, an average of one year | 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. |
| The sensitivity of professionally-collected skin samples for diagnosing scabies | through study completion, an average of one year | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The sensitivity of skin swabs for diagnosing scabies | through study completion, an average of one year | 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. |
| The sensitivity of skin scrapings for diagnosing scabies | through study completion, an average of one year | 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. |
| The sensitivity and specificity of PCR on skin scraping for diagnosing active scabies infection | through study completion | 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. |
| The sensitivity and specificity of microscopy on skin scraping for diagnosing active scabies infection | through study completion, an average of one year | 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. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Motivation for self-collection of skin samples for scabies diagnostics | through study completion, an average of one year | 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. |
| Proportion of participants whose self-sampling location is judged appropriate | through study completion, an average of one year | Assessed by a professional at T=0 \[adequate/non-adequate\] |
| Demographic, clinical and epidemiological factors which influence the sensitivity of self-collected skin samples for scabies diagnosis. | through study completion, an average of one year | Age, gender, highest level of education, signs/symptoms, living situation, skin color. source of transmission and transmission mode. |
Countries
Netherlands
Contacts
Primary ContactMatthew MC McCall, PhD
Backup ContactSaskia C van der Boor, PhD
Outcome results
None listed