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Monitoring contact sensitization to p-phenylenediamine (PPD) by patch testing with PPD 0.3% in petrolatum
Johannes Geier1, Barbara K Ballmer-Weber, Heinrich Dickel
1Information Network of Departments of Dermatology, University of Göttingen, Göttingen, Germany. jgeier@gwdg.de
Contact Dermatitis
|June 21, 2013
Summary
Patch testing with p-phenylenediamine (PPD) at 0.3% in petrolatum is a reliable method for detecting PPD sensitization. This concentration is recommended to replace the 1% PPD concentration in baseline series due to its safety and efficacy.
Area of Science:
- Dermatology
- Allergology
- Contact Dermatitis
Background:
- P-phenylenediamine (PPD) is a common contact allergen included in baseline patch testing.
- PPD at 1% in petrolatum may cause active sensitization.
- Lower concentrations, such as 0.35% PPD in petrolatum, have shown safety regarding active sensitization.
Purpose of the Study:
- To evaluate the diagnostic reliability of PPD 0.3% in petrolatum for detecting PPD sensitization.
- To compare the efficacy of PPD 0.3% pet. with PPD 1% pet. in patch testing.
Main Methods:
- A multicenter study involving 2042 consecutive patients.
- Synchronous patch testing with PPD 0.3% pet. and PPD 1% pet.
- Analysis of reaction rates, reproducibility, and diagnostic properties.
Main Results:
- PPD 1% pet. showed a 6.0% positive reaction rate, while PPD 0.3% pet. yielded 4.7%.
- The diagnostic properties of PPD 0.3% pet. were found to be good.
- A subset of patients (26%) reacting to 1% PPD did not react to 0.3% PPD, with no clinical relevance found in 69% of these cases.
Conclusions:
- Patch testing with PPD 0.3% pet. is a reliable method for detecting PPD sensitization.
- The study recommends replacing PPD 1% pet. with PPD 0.3% pet. in baseline series for improved safety and reliability.
