It is the purpose of this study to determine the concentration of 3 allergens (goldnatriumthiosulphate, methyldibromoglutharonitrile [MDBGN], parthenolide) for diagnosing allergic contact dermatitis.

The TRUE Test standard panel consists of two tape strips, panel 1 with 11 allergen patches and a negative control and panel 2, with 12 allergen patches. TRUE test panel 1 and 2 contain 23 of the most frequent contact allergens.With these 23 allergens, it is possible to detect about 60-70% of contact allergic reactions. Thus, there is a need for expanding the number of allergens included in TRUE Test in order to detect more contact allergic reactions. Therefore goldnatriumthiosulphate, methyldibromoglutharonitrile and parthenolide are developed for inclusion in a third TRUE Test panel. This study is a dose-response study using 3 dilution series to detect the optimum concentration of the 3 allergens. A phase-III study will be performed afterwards to establish the efficacy and safety of the three allergens.

Inclusion Criteria:

• Positive MDBGN patch test within the latest 5 years or positive Parthenolide patch test within the latest 5 years or positive Goldnatriumthiosulphate patch test within the latest 5 years.
• Age more or equal to 18 years.
• Signed informed consent.

Exclusion Criteria:

• Topical treatment with corticosteroids or immunosuppressives during the latest 7 days on the test area or near the test area.
• Systemic treatment with corticosteroids or immunosuppressives during the latest 7 days.
• Treatment with UV-light during the latest 3 weeks.
• Widespread active dermatitis or dermatitis on test area.
• Breast-feeding, pregnancy or insufficient contraception. If any doubt a negative urine-pregnancy test should be demonstrated or the patch test should be postponed one period.
• Subjects not able to cooperate.
• Participation in other clinical studies during the study period and 3 weeks prior to study start.