Low Dose Exposure to Oxidized R-limonene - A Repeated Open Application Test (ROAT) Study

Study Overview
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Brief Summary
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This study evaluates the clinical and molecular effect of daily exposure to low doses of the fragrance contact allergen oxidized R-limonene. Three groups of participants are included: 1) Patients with a previous positive patch test to oxidized R-Limonene, 2) patients with a previous doubtful patch test to oxidized R-limonene and 3) healthy controls with no contact allergy to oxidized R-limonene

Official Title
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Low Dose Exposure to Oxidized R-limonene - A Double Blinded Vehicle Controlled Repeated Open Application Test (ROAT) Study

Conditions
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Allergic Contact Dermatitis Due to Cosmetics

Intervention / Treatment
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* Other: ROAT with oxidized R-limonene at 1%, 0.3% and 0.1%
* Other: ROAT with oxidized R-limonene at 1%


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Positive patch test (at least one reading) or doubtful patch test (at least two readings) to oxidized R-limonene 3% pet. (with 0.33% hydroperoxides content) according to international guidelines, within the last five years. Aged 18 years or older Received written and verbal information on the study. Signed written consent form. Exclusion Criteria: Active eczema in test areas. Pregnancy or breast feeding. Treatment with topical corticosteroids or other immune-suppressants on/near test areas within two weeks prior to study start. Systemic immune-suppressant treatment within seven days prior to study start. UV exposure of test areas within three weeks prior to study start. Unable to cooperate or communicate with the investigators.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Fragrance allergic patients<br>Patients with a previous positive patch test to oxidized R-Limonene. Patients will have an initial patch test dilution series with oxidized R-limonene performed on the back followed by twice daily exposure to oxidized R-limonene at three different concentrations and a vehicle control on the forearms for up to three weeks. | Other: ROAT with oxidized R-limonene at 1%, 0.3% and 0.1%<br>* A twice daily repeated open application test (ROAT) study for up to three weeks of exposure to oxidized R-limonene at 1%, 0.3% and 0.1% concentrations<br>|
| Experimental: Possible fragrance allergic patients<br>Patients with a previous doubtful patch test to oxidized R-limonene. Patients will have an initial patch test dilution series with oxidized R-limonene performed on the back followed by twice daily exposure to oxidized R-limonene at three different concentrations and a vehicle control on the forearms for up to three weeks. | Other: ROAT with oxidized R-limonene at 1%, 0.3% and 0.1%<br>* A twice daily repeated open application test (ROAT) study for up to three weeks of exposure to oxidized R-limonene at 1%, 0.3% and 0.1% concentrations<br>|
| Experimental: Healty controls<br>Healthy controls with no contact allergy to oxidized R-limonene. Healthy controls will have en initial diagnostic patch test with oxidized R-limonene performed followed by twice daily exposure to oxidized R-limonene at one concentration and a vehicle control on the forearms for up to three weeks. | Other: ROAT with oxidized R-limonene at 1%<br>* A twice daily repeated open application test (ROAT) study for up to three weeks of exposure to oxidized R-limonene at a 1% concentration<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive ROAT (minimum score of 5) | Proportion (%) of participants with a positive ROAT | Day (D) 21 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Minimal eliciting concentration (MEC) | Threshold concentration for a positive patch test | Day (D) 7 |