The North American Contact Dermatitis Group (NACDG), founded in 1970, has members who assess subjects with suspected allergic contact dermatitis (ACD) and patch test them with the same screening allergens using a standardized procedure so that trends in delayed-type contact sensitivity can be investigated. Results have been reported on tens of thousands of patch tests performed on patients with suspect ACD presenting for evaluation of clinical disease. The research group’s initial report appeared in 1973. Since then, the patch test figures of the NACDG have been intermittently published.
This report evaluates the trends in the results of patch testing. The patch test reactions were surveyed retrospectively. The results were statistically compared between 1970 and 2002 because appropriate interpretation of the numbers has public health opportunities.