Clinical Evaluation of T.R.U.E. TEST® Panel 3.2 Allergens: Dose Response

We propose a prospective, multi-center, double-blind, randomized study comparing the diagnostic performance (primary) and safety (secondary) of 3 concentrations of Disperse blue 106 and 4 concentrations of Bronopol in 40 adult subjects (20 subjects per allergen) with a clinical history of contact dermatitis and a positive patch test (current or previous) to the corresponding reference petrolatum allergen ("sensitives").

Primary endpoint:

To evaluate the diagnostic performance of Disperse blue 106 and Bronopol T.R.U.E. Test allergens in 20 adult subjects per allergen with a clinical history of contact dermatitis and a positive patch test to the respective reference allergen. Evaluations will include:

* Determination of the lowest concentration eliciting positive skin reactions (+1 or +2) in 70-90% of sensitive subjects.
* Frequency of positive, negative, doubtful and irritant reactions for each allergen and tested concentration.
* Concordance/discordance as compared to the corresponding reference petrolatum allergen.

Secondary endpoint:

To evaluate the safety of Disperse blue 106 and Bronopol T.R.U.E. Test allergens in 20 adult subjects per allergen with a clinical history of contact dermatitis and a positive patch test to the respective reference allergen. Evaluations will include:

* The frequency of tape-induced irritation at the test site, incomplete panel adhesion, and subject-reported sensations of itching or burning.
* The frequency and characterization of adverse events and serious adverse events.
* The frequency and characterization of late and/or persistent reactions.

Eligibility Criteria:
Inclusion Criteria:

* Current or previous symptoms and/or history consistent with allergic contact dermatitis, and positive patch test (within the past 5 years) to Bronopol OR Current or previous symptoms and/or history consistent with allergic contact dermatitis, and a positive patch test (within the past 5 years) to Disperse blue 106 or Disperse blue 106/124 allergen mix.
* All subjects must be adults (18 years of age or older) and otherwise in good health.
* Premenopausal female subjects must consent to a urine pregnancy test; results must be negative for study inclusion.
* Informed consent must be signed and understood by each subject, and consistent with all institutional, local and national regulations.

Exclusion Criteria:

* Subjects unable to meet inclusion requirements.
* Women who are breastfeeding or pregnant.
* Topical treatment during the last 7 days with corticosteroids or other immunosuppressive agents on or near the test area.
* Systemic treatment during the last 7 days with corticosteroids (equivalent to \> 10 mg prednisone) or other immunosuppressive agents.
* Treatment with ultraviolet (UV) light (including tanning) during the previous 3 weeks.
* Acute dermatitis outbreak or dermatitis on or near the test area on the back.
* Subjects unable to comply with patch test study requirements including multiple return visits and activity restrictions (e.g., protecting test panels from excess moisture due to showering or vigorous activity).
* Subject participation in clinical trials of investigational drugs, treatments or devices other than T.R.U.E. Test during this study or 3 weeks prior to inclusion in this study.