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.

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

The forearm randomized to SLS and the order in which the different concentrations of thiurams and carbamates and the control solution are applied to the skin, will be blinded for the reader of the skin reactions and the latter also for the participant.