Background: Patch testing remains the standard for the diagnosis of allergic contact dermatitis. The validity and usefulness of a standard patch test allergen series has not been addressed adequately by previous studies.
Objective: We sought to examine the utility of the standard allergen series as a sole screening tool in the diagnosis of allergic contact dermatitis.
Methods: The charts of 732 patients referred for patch testing were reviewed for positive patch test results. The group of patients with positive reactions was stratified into two groups based on the clinical relevance of their reactions. These groups were subsequently analyzed to determine whether the reactions were to part of the standard series of allergens or to part of a supplementary group.
Results: Of patients tested, 50% had a positive patch test. Of those, 221 (30%) had reactions deemed clinically relevant. Only 23% of patients with positive patch tests reacted to an allergen(s) in the standard series exclusively. When adjusted for clinical relevance, only 15.7% of patients were completely evaluated with the standard series of 20 allergens.
Conclusion: The standard allergen series of 20 allergens available in the United States is limited as a screening tool when used alone in the evaluation of patients with allergic contact dermatitis.