Contact Allergy to Rubber Accelerators – a Clinical Study

Overview

This study will investigate what concentrations of the most common thiurams and carbamates that elicit allergic contact dermatitis under patch test and what concentrations of the rubber accelerators that elicit allergic contact dermatitis by repeated exposures under simulated use conditions. Further, it will investigate whether a damaged skin barrier as caused by wet work increase the severity of the allergic contact dermatitis. The participants will be assigned to either the SLS (sodium lauryl sulfate)-group or non SLS-group. For the participants of the SLS-group, one volar forearm will be randomized to be pre-irritated with a soap i.e. detergent: sodium lauryl sulfate (SLS) for 24 hours to simulate wet work. The participants of the non SLS-group will not be pre-irritated with SLS. Following this, the participants' volar forearms will be exposed to thiurams or carbamates and a control solution every night for 7 nights to simulate the repeated exposure to rubber gloves with accelerators. The skin reactions will be read cf. current international guidelines and further quantified using laser Doppler flowmetry. During the study, all participants will be patch tested on the upper back with rubber accelerators to investigate their current degree of sensitization and the dose-response relationships.

Full Title of Study: “Improving the Diagnosis and Prevention of Contact Allergy to Rubber Accelerators”

Study Type

• Study Type: Interventional
• Study Design
  • Allocation: Non-Randomized
  • Intervention Model: Parallel Assignment
  • Primary Purpose: Prevention
  • Masking: Double (Participant, Outcomes Assessor)
• Study Primary Completion Date: October 1, 2024

Interventions

• Other: Rubber accelerators and control chamber/solution for NON-SLS group
  • Repeated exposure to rubber accelerators and control chamber/solution on arms. Three different concentrations of rubber accelerators and one control chamber/solution will be applied on the arms.
• Other: SLS
  • Exposure to SLS on a randomized arm
• Other: Rubber accelerators and control chamber/solution for SLS group
  • Repeated exposure to rubber accelerators and control chamber/solution on arms. Two different concentrations of rubber accelerators and one control chamber/solution will be applied on both arms.
• Other: Patch test on back
  • Patch test on the back with thiurams or carbamates in different concentrations and a control chamber/solution

Arms, Groups and Cohorts

• Experimental: NON-SLS, Allergic participants
  • Participants allergic to thiurams or carbamates assigned to the NON-SLS group.
• Experimental: NON-SLS, Control participants
  • Participants not allergic to thiurams or carbamates assigned to the NON-SLS group.
• Experimental: SLS, Allergic participants
  • Participants allergic to thiurams or carbamates assigned to the SLS group.
• Experimental: SLS, Control participants
  • Participants not allergic to thiurams or carbamates assigned to the SLS group.

Clinical Trial Outcome Measures

Primary Measures

• Reading of skin reactions
  • Time Frame: Day 0, Day 1 (only participants’ arms in the SLS-group), Day 2 and Day 3 or Day 4, and Day 7, and Day 8. Further, eventually, if any reactions occur up to Day 16.
  • Development of dermatitis by reading of skin reactions based on international dermatitis scoring guidelines.
• Skin blood flow
  • Time Frame: Day 0, Day 1 (only participants’ arms in the SLS-group), Day 2 and Day 3 or Day 4, and Day 7, and Day 8. Further, eventually, if any reactions occur up to Day 16.
  • Changes in blood flow on the arms using laser doppler flowmetry

Participating in This Clinical Trial

Allergic participants Inclusion Criteria:

• Adults ≥18 years old – Sensitized to thiurams, carbamates or both. – Received written and oral information about the study. – Signed written consent form Exclusion Criteria:

• Dermatitis on back or arms – Tattoos or significant scar tissue on exposure areas – Pregnancy – Breast feeding – Recently given birth – Treatment with systemic immunomodulators within the last 4 weeks – Treatment with local immunomodulators on arms or back within the last 4 weeks – Excessive ultraviolet light on arms or back within the last 4 weeks Healthy Controls: Inclusion Criteria:

• adults ≥18 years old – Received written and oral information about the study. – Signed written consent form Exclusion Criteria:

• Sensitized to thiurams, carbamates or both. – Occupational or domestical use of rubber gloves. – History of atopic dermatitis or contact dermatitis – Dermatitis on back or arms – Tattoos or significant scar tissue on exposure areas – Pregnancy – Breast feeding – Recently given birth – Treatment with systemic immunomodulators within the last 4 weeks – Treatment with local immunomodulators on arms or back within the last 4 weeks – Excessive ultraviolet light on arms or back within the last 4 weeks

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

• Lead Sponsor
  • National Allergy Research Center, Denmark
• Provider of Information About this Clinical Study
  • Sponsor
• Overall Contact(s)
  • Christoffer Kursawe Larsen, MD, +4538673940, christoffer.kursawe.larsen.01@regionh.dk