Twenty-eight-day follow-up of patch test reactions to p-phenylenediamine and p-phenylenediamine dihydrochloride : A multicentre study on behalf of the European Environmental and Contact Dermatitis Research Group
Background: There is an ongoing discussion on whether routinely patch testing with p-phenylenediamine (PPD) 1.0% pet. is safe, owing to the risk of patch test sensitization. Late-appearing patch test reactions may reflect patch test sensitization, but may also be attributable to a low degree of pre-existing sensitization. Objectives: To follow the positive patch test reactions to PPD and its salt